Identifying optimal field management strategies for conservation of wintering birds on intensive farmland

1. Title of Project:
A Comparative Study of Winter Bird
Assemblages on Agricultural Pasture, Winter
Cereal and Cereal Stubble
Identifying the Optimal Field Management Strategies for the
Conservation of Wintering Birds on Intensive Farmland
Author: Fintan Damer
S00174270
Academic Year: 2018-2019
Supervisor/s: Dr. Dolores Byrne
This project is submitted as fulfilment of the M.Sc. Degree in Environmental
Protection, Institute of Technology, Sligo.

2. Declaration:
I certify that the content of this project is entirely my own work and is submitted in fulfilment of
the MSc Degree in Environmental Protection at the Institute of Technology, Sligo.
Any material adopted from other sources is duly cited and referenced and acknowledged as such.
I have read and understand the policy regarding plagiarism in the Institute of Technology Sligo.
Signed: __________________________
Date: _____________________________
Student No. S00174270

3. Abstract
The purpose of this study was to establish baseline information and insight into over wintering
farmland bird richness and abundance on intensively managed farmland in east County Meath,
Ireland, a location which has not been well studied to date. In the context of declining farmland
bird populations, there is interest in the optimal farm and field management strategies for
enhancement, even in the more intensified landscapes. The three main field management types
in the area were surveyed; pasture, winter cereal and cereal stubble. Surveying of bird
assemblages was carried out on three occasions in the winter of 2018-2019 including discrete
observations, field boundary and transects walks. Additionally, field boundary appraisals and
field layer evaluations were conducted and an examination of the relationship each of the field
managements types coupled with its boundary characteristics and fields layer attributes had,
with the farmland bird species present. We found that although cereal stubble fields and
boundaries may support higher bird richness and abundances, they do not possess all the habitat
characteristics needed to sustain the wider assemblage of farmland birds. Pasture and winter
cereal fields and boundaries support other attributes required by certain bird species, some of
which are of conservation concern. Additionally, the presence of niche microhabitats e.g.
patches of bare soil, water accumulations, substantial water filled ditches etc. can support
species which might otherwise have been absent. We concluded that at the landscape level, a
diversity of field management types, multiplicity of field boundary characteristics and field
layer attributes at both farm, field and individual boundary level, provides a mosaic of habitats
types necessary to maximise overwintering farm bird diversity. Moreover, we concluded that
intensively managed farmland may be largely overlooked as a valuable contributor to the
conservation of wintering farmland birds.

4. Acknowledgements
We would like to thank all the farmers who kindly allowed access to their land throughout the
field survey period of this study. In particular, we’d like to thank Darragh McCullough who
enthusiastically gave of this time to provide us with valuable information into the running of
his farm and brought us on a whistle-stop tour of his property which largely guided the site
selection process for the field surveys.
Invaluable in the design, development and ultimate completion of this study was the
unwavering support, guidance and encouragement provided by Dolores Byrne, the project
supervisor, without whom this dissertation may well have faltered on numerous occasions in its
progression.
Lastly but by no mean least huge thanks must go to my family and in particular my wife Jane
who has had to hold the fort due to my sporadic availability over the last 12 months. None of
this would have happened without her.

5. Contents
1. Introduction................................................................................................................................... 1
2. Literature Review........................................................................................................................... 1
2.1 Historical Perspective............................................................................................................... 1
2.2 Recent Changing Practices and Agricultural Intensification ....................................................... 2
2.3 Changes in Cereal Cultivation ................................................................................................... 3
2.4 Grassland Management and Intensification.............................................................................. 6
2.5 Monoculture and Sward /Crop Construct ................................................................................. 8
2.6 Field Boundaries and Hedgerows.............................................................................................. 9
2.7 Predation Risk .........................................................................................................................11
3. Objectives of the study..................................................................................................................12
4. Methodology ................................................................................................................................12
4.1 Site Selection...........................................................................................................................12
4.2 Timing of Field Survey Work....................................................................................................15
4.3 Collection of Winter Bird Data.................................................................................................16
4.3.1 Bird Functional Feeding Groups ........................................................................................19
4.4 Collecting of Habitat Data........................................................................................................20
4.4.1 Field Boundary Appraisals.................................................................................................20
4.4.2 Field Layer Evaluation.......................................................................................................23
4.4.3 Data Analysis Methodology ..............................................................................................25
4.4.4 Explanatory Variables .......................................................................................................25
4.4.5 Statistical Analysis ............................................................................................................27
5. Results ..........................................................................................................................................30
5.1 Bird Survey Results..................................................................................................................30
5.2 Field Boundary Results ............................................................................................................40
5.3 Field Layer Results...................................................................................................................44
5.4 Testing for Significance between Management Types and Abundance, Species Richness and
Shannon Index ..............................................................................................................................45
5.5 Cluster Analysis and NMS ........................................................................................................48
6. Discussion.....................................................................................................................................49
6.1 Influence of Landscape Scale Management Types ...................................................................50
6.2 Association with Cereal Stubble...............................................................................................51
6.3 Association with Winter Cereal................................................................................................53
6.4 Association with Pasture .........................................................................................................54
6.5 Sward Structure ......................................................................................................................55

6. 6.6 Bare Ground/Crop Cover.........................................................................................................56
6.7 Field Boundaries......................................................................................................................59
6.8 Dwellings and Farmyards.........................................................................................................62
6.9 Farm birds of Conservtion Concern..........................................................................................64
7. Conclusions...................................................................................................................................65
8. References....................................................................................................................................73
Appendices.......................................................................................................................................86
Appendix i. Total Bird Species List .................................................................................................87
Appendix ii. Bird Survey Sheets - Survey Set 1 ...............................................................................89
Appendix iii. Bird Survey Sheets - Survey Set 2 ..............................................................................99
Appendix iv. Bird Survey Sheets – Survey Set 3............................................................................109
Appendix v. The maximum abundance of each species per individual field, the total maximum
abundance of all birds for each of the field and the total bird species count per individual field..119
Appendix vi. Functional Feeding Groups of all Species.................................................................120
Appendix vii. Hedgerow Boundary Appraisals..............................................................................121
Appendix viii. FBEGS Score for all Field Boundaries......................................................................131
Appendix ix. Hedgerow Woody species Surveys .........................................................................132
Appendix x. Field Layer Surveys...................................................................................................158
Appendix xi. Species richness descriptive statistics......................................................................164
Appendix xii. Tukey’s Posthoc test to determine nature of the significant differences in bird species
richness between management types .........................................................................................165
Appendix xiii. Tukey’s Posthoc test to determine nature of the significant differences in bird
abundance between management types.....................................................................................166
Appendix xiv Multiple comparisons……………………………………………………………………………….………….167
Appendix xv General field characteristics including size, overall hedgerow length and hedgerow
density per field……………………………………………………………………………………………………..………………………167
Appendix xvi Cluster analysis of bird data………………………………………………………………………………….168
List of Tables
Table 1 Cereal crop percentage change in area grown between 2004 and 2012 (source DAFM, 2012) 4
Table 2 DAFM, 2013. Quantities of Pesticides used, Kg/ha., on Area of Grassland Grown................... 5
Table 3 Teagasc, 2017. Soil Index System ........................................................................................... 7
Table 4 Surveyed fields and general management.............................................................................14
Table 5 FBEGS scores and grades ......................................................................................................22
Table 6 DAFOR Scale .........................................................................................................................23

7. Table 7 List of explanatory variables utilised to explain richness & abundance ..................................25
Table 8 Bird species abundance and richness per field management type .........................................31
Table 9 Birds of conservation concern that occurred in the field surveys...........................................36
Table 11 Primary results of the field and boundary surveys across all management types.................41
Table 12 FBEGS mean scores and standard deviations for all fields and field management types ......41
Table 13 Mean woody species richness in field boundaries of the three management types surveyed
.........................................................................................................................................................43
Table 14 Mean sward height and bare ground cover per field and per field management type .........44
Table 15 One-way ANOVA with Tukey’s post hoc test comparing species richness & abundance with
pasture, winter cereal and stubble....................................................................................................46
Table 16 Kruskal Wallis H test, Testing differences between species richness across functional feeding
groups ..............................................................................................................................................46
Table 17 Spearman's rank correlation coefficients of species richness, abundance and Shannon’s
Index with explanatory variables (n=10)............................................................................................47
Table 18 Spearman's rank correlations between birds categorised by functional feeding groups and
explanatory variables........................................................................................................................48
List of Figures
Figure 1 DAFM, 2012. Pesticide uses in Ireland................................................................................... 5
Figure 2 Study area in east Co. Meath, Ireland ..................................................................................13
Figure 3 A 'W' transect walk for F3, a winter cereal field ...................................................................24
Figure 4 Average bird abundance per field management type...........................................................33
Figure 5 Percentage bird species abundance per field management type (proportionally per hectare)
.........................................................................................................................................................33
Figure 6 Average bird species richness per field management type ...................................................34
Figure 7 Mean species abundance of functional feeding groups across all field types........................35
Figure 8 Max bird abundance per field and per field management type for five farm birds of
conservation concern........................................................................................................................37
Figure 9 NMS ordination and biplot of the10 fields sampled for winter birds. The vectors of the
dominant environmental variables (FBEGS & hedgerow density) are superimposed on the ordination
graph................................................................................................................................................49
List of Plates
Plate 1 Wet area of Field F7 where snipe, moorhen and teal occurred ..............................................39
Plate 2 Right - Yellowhammer on stubble field; Left Bullfinch a shy inhabitant of unmanaged
hedgerows (Source: Caschera V.)……………………………………………………………………………………………………..40
Plate 3 F10, a winter cereal field which had the highest FBEGS score of 39.5.....................................42
Plate 4 F8, a winter cereal field which had the lowest FBEGS score of 11. .........................................43
Plate 5 F3, field with the highest boundary hedgerow standard deviation for woody species richness
.........................................................................................................................................................44
Plate 6 F1 Pasture field with area of bare ground circled, used by foraging finches. ..........................58
Plate 7 Habitat preference and avoidance of yellowhammer.............................................................61
Plate 8 Locations of species associating with farmyards in F11 & F9..................................................63

8. 1
1. Introduction
Farms with designation of High Nature Value (HNVf) in Ireland, tend to get prioritised for
monitoring particularly if they are of type I, farms with a high proportion of semi natural habitat
or type II, farms with smaller areas of semi natural habitat occurring in mosaics with more
intensive agriculture (Smith et al, 2010). There is a third type, type III, which is intensively
managed farmland with little semi-natural habitat which may support species of conservation
concern such as breeding waders or populations of overwintering birds. Sullivan et al., (2011)
identified the need for a significant EU wide policy objective for the safeguarding of
biodiversity not just within protected Natura 2000 sites but also those areas outside the
designated sites. The current study looks at an example of type three HNVf, intensively
managed, undesignated pasture, winter cereal and cereal stubble fields and their boundaries to
ascertain their value for overwintering bird species populations and their potential to support
species of conservation concern. This type of farmland is known to support overwintering birds
but there are no specific studies for the selected study area in east Co. Meath which look at the
comparative value of the three main management activities for overwintering birds. As pressure
on the Common Agricultural Policy (CAP) budget grows, and the requirement for higher levels
of environmental attainment also grows, understanding the capacity of farmland types to
support nature is vital to facilitate well-designed and effective agri-environment measures.
2. Literature Review
2.1 Historical Perspective
Farming and farmland as we know it, is believed to have evolved in the late stone age about
12,000 years ago, in an area known as the ‘fertile crescent’, now occupied by modern day
Turkey, Iraq, Syria and Jordan (Newton, 2017). The expansion of agriculture reached Britain
about 6500 years ago and Ireland about 1000 years later (Whitehouse, 2013). In global terms,

9. 2
agriculture has altered in the region of 75% of the world’s ice-free terrestrial landscapes
(Ramankutty et al., 2008) and is considered the principal driver of habitat modification and
decreased ecosystem services (Foley et al., 2011). The clearance of forest for the cultivation of
large grained grasses, precursors to our modern-day cereals, allowed for a complete
restructuring of human society (Diamond, 1997). In Europe, the overwhelming anthropogenic
landscape changes, from canopy trees cover to open landscape, led to an increase in floristic
diversity (Kornas, 1988) and most probably, concurrently an increase in avian diversity
(Harrison, 1988) in this modified semi natural landscape. Despite its artificial nature and it
relatively short evolutionary transition, farmland has progressed to support a community of
open country bird species i.e. farmland that has very few trees and limited shrub cover (Donald
et al, 2002). The various habitats that can exist on agricultural land have given rise to bird
communities of both a generalist and specialist nature (O’Connor & Schrubb, 1986) and it can
be presupposed, of a higher diversity than would have existed in a fully forested European
landscape.
2.2 Recent Changing Practices and Agricultural Intensification
While historically the change from a largely forested landscape to an open country scenario has
been beneficial to many bird species, there has in more recent times, been a marked change in
the fortunes of farmland birds. Declines in diversity, numbers and range in Britain are occurring
on farmland habitats faster than any other habitat types (Fuller et al., 1995) and these changes
are not confined to the UK. Many EU studies suggest that declines in biodiversity in general,
have been occurring most markedly since the 1950’s and are most closely linked to agricultural
changes (Donald et al.,2001; Robinson & Sutherland, 2002).
There has been a recent and well publicised, extensive decline in global biodiversity, which has
added credence to the major global conversation around climate and the extinction crisis
(WWF, 2018; Butchart, 2010). Specifically, there has been a well-documented widespread and

10. 3
severe reduction in farmland biodiversity across Europe over recent decades (Robinson, 2002;
Siriwardena, et al., 1998) with most farmland bird species in the Britain and Ireland exhibiting
marked declines (Balmer, 2013), some by more than as 90% since 1970 (Newton, 2017).
Despite this, European lowland farms are said to provide both breeding and wintering habitat
for nearly 120 bird species which represents the largest number of bird species sustained by any
habitat type in Europe (Tucker, 1997).
Agricultural intensification and specialisation have been blamed for biodiversity loss over the
last century (Donald et al., 2001b). The loss of breeding and foraging habitat due to changes in
agricultural practices and management intensification, has resulted the loss of food resources
both in terms of seed and invertebrate availability (Fuller, 2000). Lower insect and plant
heterogeneity, driven by agricultural intensification has been linked to farm bird declines
(Donald, 1998; Benton et al., 2002).
Consecutive common agricultural policies reforms (CAP) have enabled the push towards
increased productivity intensification, specialisation and expansions (Ghaffar & Robinson,
1997) and in effect, the agricultural landscape has evolved parallel to the CAP’s price support
programmes and resulted in decreased habitat availability and increased farmland homogeneity.
The most recent CAP did go some way to address the loss of mixed farming practices and
reverse the negative outcomes of previous reforms by promoting crop diversification. Arable
farms greater than 30 ha. are now required to grow at least three crops and any one crop cannot
comprise of more than 75% and the two main crops together not more than 95%, thus promoting
farm heterogeneity and idealistically, biodiversity too (EU, 2013).
2.3 Changes in Cereal Cultivation
A root cause in the decline of granivorous birds is thought to be linked to the move towards
autumn sown cereals and the parallel decline in over wintered cereal stubble (Wilson, 2009).

11. 4
Other studies have also alluded to this and suggest that land-use change, such as the switch to
autumn sown cereal, is thought to be the main driver in the population change of several
farmland bird species (Chamberlain et al., 2001; Eggers et al., 2011). Table 1 below tabulates
the rise in the major autumn sown cereals over spring sown cereals in Ireland, in an eight-year
period, 2004 -2012.
Table 1 Cereal crop percentage change in area grown between 2004 and 2012 (source DAFM, 2012)
Crop 2004 2012 % change
Spring Barley 163,200 ha 150,378 ha -8
Winter Barley 20,500 ha 40,717 ha +99
Spring Wheat 31,200 ha 13,314 ha -57
Winter Wheat 71,500 ha 83,751 ha +17
In addition to the reduced availability of dropped grain in an autumn sown tillage field, there is
also the prospect of reduced availability of alternative food resources such as weed seeds from
in crop weed growth, due to the use of herbicides (Geiger et al., 2010). This food supply would
likely be available in an over wintered stubble fields that would not have been sprayed for
weeds since the previous growing season. Declines in insects as a food resource in the breeding
season for species which are exclusively insectivorous, as well as granivorous species that
switch to insects during the breeding season (primarily for the purpose of feeding their young),
has been identified as another important driver (Campbell, 1997; Schaub, 2010). Overall there
has been an 18.4% rise in pesticide use in Ireland between 1990 and 2004 (OECD, 2010). Given
that Ireland has almost 93% of its agricultural area used (AAU) under grassland, consisting of
grass, rough grassing and commonage (CSO, 2012) and the low quantities of pesticide
requirements here (Table 2) with the notable exception of herbicides, it would seem that the
remaining 7% AAU, which mostly comprises of cereal, has received the bulk of this pesticide
rise (see Figure 1).

12. 5
Table 2 DAFM, 2013. Quantities of Pesticides used, Kg/ha., on Area of Grassland Grown
Quantities of Pesticide Types Used on Grassland 2003-2013
Kg/ha on area grown
Pesticide Type 2003 2013
Fungicide 0 0
Herbicide (incl. spot treatment) 0.11 0.11
Insecticide 0.00005 0
Molluscicide 0 0.00001
Growth regulator 0 0
Seed treatments 0 0
Figure 1 DAFM, 2012. Pesticide uses in Ireland.
High applications of pesticide use have been linked to declines in skylark, Alauda arvensis
(Ewald et al., 2002) and yellowhammer, Emberiza citrinella (Morris et al., 2005). Declines in
wintering bird species on farmland therefore could potentially be linked to the decline in insect
availability in the breeding season, even in the case of species that switch back to foraging on
cereal for the winter and in the probability that there was copious availability of winter grain
(Newton, 2004). In other words, successive high over winter survival rates followed by
successive poor breeding season successes, will still ultimately affect the overall abundance of
Fungicide
46%
Herbicide
25%
Insecticide
11%
Molluscicide
1%
Growth Regulators
9%
Seed Treatment
8%
PESTICIDE USED ON CEREAL CROPS GROWN IN
IRELANS 2012.

13. 6
birds. Collectively, poor survival rates over the winter coupled with poor breeding successes,
could rapidly result in the disappearance of many farmland bird species.
2.4 Grassland Management and Intensification
Most investigations into declines of farmland birds has focused on arable farming systems with
many links to its intensification (e.g. Buckingham et al., 2006). However, the decline in
farmland birds, particularly seed eating birds, happens also to coincide with the intensification
of grassland farming practices (Chamberlain & Fuller, 2000). The intensification in grassland
management has almost certainly led to an increased scarcity of seed and decreased insect
quantity and diversity and consequently their availability to foraging birds (Vickery et al.,
2001).
A multitude of reasons might exist for low availability of food items for bird in intensively
managed pasture. The use of herbicides reduces plant heterogeneity by eliminating perennial
weeds and so eradicates associated invertebrates and potential seed availability (Newton, 2004).
An enquiry made with the relative farmers involved in this study confirmed the habitual use of
the herbicide glyphosate, both as a pre sowing weed control of arable crops and as a preharvest
desiccant of cereal crops (which will also suppress weeds persistence). Improved sward
heterogeneity has been proven to ensure positive outcomes for field level foraging birds such
as Skylark (Morris et al., 2004). Residues of anti-helminthic drugs (deworming drugs) are
excreted in the faeces of treated livestock and can subsequently reduce the number of
invertebrates (associated with dung) available as prey items for birds (McCracken & Foster,
1993). High inputs of inorganic fertilizer are believed to affect the abundance and diversity of
the larger invertebrate prey species (Beintema et al., 1990; Fenner & Palmer, 1998). Moderate
inputs of both organic and inorganic fertilizers are generally believed to be of benefit to
grassland invertebrates particularly earthworms (Keiller et al., 1995) but organic inputs such as
slurry are generally though be more beneficial (Marshall, 1977). That said, high applications of

14. 7
either organic or inorganic can be detrimental (Unwin & Lewis, 1986). High applications of
organic fertilizer although potentially deleterious at the time of application, show a marked
benefit to the success of bibionid larvae (march fly) and leatherjackets the following year, both
of which are important prey items for birds (McCracken et al., 1995). Winter field use by some
bird species such as starling or redwing, may be positively associated with application of
organic matter (Tucker, 1992). In terms of accessibility to birds, excessive sward height
however may lessen the attractiveness and the ability to forage efficiently (Milsom et al., 1998).
Liberal application of fertilizer has also been shown to be related to reductions in botanical
diversity which subsequently reduces the availability of seed for both summer and winter birds
(Vickery et al., 2001).
In general, for the purpose of enhancing crop growth, recommended applications of inorganic
fertilizer both for grassland and tillage are deciphered according to the soil index levels,
between 1-4 (Teagasc, 2017) (See Table 3), which indicate the likely response of a crop to
fertilizer application.
Table 3 Teagasc, 2017. Soil Index System
Soil Index System
Soil index Level Index Description Response to Fertilisers
1 very low Definite
2 low Likely
3 Medium Unlikely
4 Sufficient/Excess None
For index level 1 for instance, winter barley has a maximum limit of 180kg/ha/yr. N while
winter wheat has a maximum limit of 210kg/ha/yr. N, except were projected yield can be proven
to be above 8.5t/ha. (EU, 2014). For grasslands and in addition to index levels, application rates
will also depend on stocking rates, which considers total available nitrogen (i.e. organic

15. 8
excretions of grazing livestock plus organic and inorganic applications). Above the stocking
rate of 210kg/ha/yr. N, the upper constraint limit is determined by the nitrogen regulations for
grassland, except where a derogation applies (Teagasc, 2019). Nationally average application
rate for grassland are at 100kg/ha/yr. (2005), winter barley at 166kg/ha/yr. (2015) and winter
wheat at 190kg/ha/yr. (2015) (Dillon et al., 2018). These limits and rates are included here as
an indication as to what might constitute ‘moderate’, ‘liberal’ or ‘high’ applications, that could
be detrimental to the availability of food for bird assemblages. An enquiry made with one of
the landowners in this study confirmed that pasture receive 250kg/ha/yr. N. which constitutes
very high application of inorganic fertilizer. The same landowner also applied 150kg/ha/yr. N.
to cereal crops which could be considered moderate. It’s worth noting too that dairy farms use
approximately twice the amount of nitrogen fertilizer compared to beef or sheep farms (Vickery
et al., 2001). The grassland referred to above are utilised for dairy grazing and silage
production. A fuller investigation as to the possible implications of fertiliser use on bird
diversity or abundance on these survey sites or indeed farmland in the wider landscape, is
beyond the scope of this study.
2.5 Monoculture and Sward /Crop Construct
As with the use of organic fertilisers and selective herbicides, the move towards regular
reseeding of grassland with primarily monoculture ryegrass Lolium sp., has produced grass
dominant dense uniform swards (Buckingham, 2006), which has not coincidentally coincided
with declines in grassland farm birds across Europe (Donald et al., 2001b). This type of dense
and tall vegetation structure has been shown to influence foraging use by birds in three ways;
the availability of food, predation risk and food accessibility (Buckingham, 2006). Perkins et
al, (2000) found that fields with a mixtures of vegetation heights from bare earth to tall grass
are the most likely grassland types at maximising the variety of bird species able to exploit them
as a foraging habitat in winter. Uniform tall sward and conversely short swards where favoured

16. 9
by different sub-sets of grassland bird species. A deeper denser sward makes ease of access by
some bird species more difficult even if food is readily available (Whittingham & Evans, 2004).
The visibility of available food may also be affected (Devereux, 2004).
2.6 Field Boundaries and Hedgerows
Bird/field boundary interaction can have a significant influence on the species present in any
farm field. The influence of field boundaries on the assemblages of farmland birds has been
relatively well investigated regarding breeding birds, however, the status of winter bird
assemblages is less well studied (Moles 1974; Parish et al. 1994). Primarily discussed here is
the presence or absence of hedgerows and the structural characteristics of the hedge itself,
which may influence winter bird usage. The presence or absence of trees and ditches will also
be considered. Some bird species rely on hedgerow almost entirely for their existence while
other only use them periodically (Johnson & Beck, 1988). Several species are considered
hedgerow specialists, including dunnock Prunella modularis, linnet Linaria cannabina,
goldfinch Carduelis carduelis, yellowhammer and greenfinch Chloris chloris (Fuller et al.,
2001). Other species, such as skylark, actively avoid hedgerows (Hinsley & Bellemy, 2000)
and will seek out fields where they are absent or are heavily managed. Hedgerows that are
trimmed to 1.2m or less were found to support fewer species and lower abundance than
unmanaged matures hedgerows (Parslow, 1969). Parish et al., (1995) found that the abundance
of many species was strongly influenced by woody species variables such as hedgerow height
width and length and the number of trees and their heights. However, management practices
which may be associated with species richness such as tall hedges or trees, may be just as likely
to be associated with negative impacts on rare or declining species (Parish et al., 1994). These
disparities between specific bird species regarding their use or refrainment of use of hedgerows
or field with hedgerows, means that no single descriptor for hedgerow structure and
management can meet the needs of all the farmland birds (Hinley & Bellemy, 2000). That said

17. 10
hedgerows provide multi-functional services for those species that do rely on their presence.
Tall and broad hedges with greater berry abundance particularly Hawthorn, Cratageaus
monogyna will provide winter food for many bird particularly trushes, Turdidae sp. (Sparks
and Martin, 1999). As well as providing food, hedgerows provide physical shelter (Arnold,
1983; Moles and Breen, 1995) and coverage from predators which allows them to exploit
nearby in field foraging resources, which, were it not for the presence of the hedgerow refuge,
they may not have risked exploiting at all (Cracknell, 1986). Yellowhammers for example are
known to forage close to hedgerows and seldom venture into the central part of fields (Robinson
& Sutherland, 1999), ostensibly to allow for the shortest flight possible to reach the safety of a
hedgerow.
Another somewhat related issue to field boundaries, is field size. Field size by itself may not be
a significant factor in how or if birds choose to use a field and their use may be more closely
association with the presence or absence of boundary hedgerows, the proximity of that
hedgerow to the point of foraging and the hedgerows structural dominance in the field. One
recent study however did find a direct correlation between bird assemblages and field size.
Smaller average field sizes were shown to be associated with higher abundance and species
richness in arable fields (Šálek et al., 2018). McMahon & Whelan (2013) however found that
small positive responses by some species to increasing field size in their study, should not be
considered on its own and should be construed more correctly as a positive response to field
boundary density. The association of increased field size and (consequently) reduced hedgerow
density, with agricultural intensification, was also highlighted by a corelative study between
sites in east and west Germany, with respectively larger (ca. 20 ha.) and smaller (ca. 3 ha.)
arable field sizes. Bird species abundance and richness within the field centres was highest in
the small fields of the West, except for skylarks, which showed a strong preference for the open

18. 11
field conditions provided by field centres in the larger fields in the east of the country (Gayer,
2019).
2.7 Predation Risk
Proximity to hedgerows is an important factor for influencing bird assemblages either positively
or negatively. Similarly, predation risk can also exist depending on crop height or crop density.
Birds which forage at field level may perceive different risks potentials depending on the crop
height. In a study of stubble fields, granivorous passerines (primarily finches) show a preference
for short stubble while other species such as skylark, Pigeon species Columbidae and meadow
pipits Anthus pratensis preferred taller stubble (Whittingham, 2006). This was perceived to be
as a result of alternative strategy employed by the specific species to evade predation. It is
possible however that some species may choose to forage on what they may think of as a site
of higher risk if they are rewarded by higher energy gain due to more plentiful food being
present or being more easily accessible (Butler et al., 2005). In general though, passerine
species are likely to prefer the shorter stubble due to reduced visual obstruction and therefore
early escapement to the cover of a nearby hedge although other species such as skylark or
meadow pipit employ the crypsis strategy of concealment and or camouflage in longer
vegetation (Butler et al., 2005). Similar strategy may also be employed in grassland pasture of
varying heights. lapwing and golden plover for instance show preferences for pasture with short
swards (Milsom et al., 1998). However, this choice may not be entirely for the purpose of
predator detection and the feeding strategy, whereby they rely on visual cues, may have a role
to play (Metcalfe, 1985). To add to this, correlations also seem to exist between sward height
and the extent of field enclosure (Milsom et al., 1998). Skylark are known to utilise field centres
rather than marginal spaces for foraging (Donald, et al., 2001a) and only move closer to
hedgerows once food becomes depleted in the field centre (Robinson & Sutherland, 1999),
suggesting their reticence at occupying a field space that restricts their view.

19. 12
3. Objectives of the study
The primary objective of the study was to examine the value of three chosen field management
types; pasture, winter cereal and cereal stubble, for over wintering farmland birds. By
determining the bird occupancy levels (richness and abundance), the aim was to identify the
optimal field management type by detecting the field attributes which have the greatest
propensity to support winter bird assemblages. Specifically, the aim was to investigate and
compare grazed grasslands (pasture) and cereal fields, in the form of winter cereal and over
wintered cereal stubble (cereal stubble) on intensive farmland in east Co. Meath Ireland and to
potentially address the current gap in knowledge on over wintering birds in the region. An
unbiassed sample reflective of the cross-sectional farm and field types in this region was to be
selected. We intended to investigate the field management practices, field and boundary
vegetation and field and boundary physical characteristics likely to influence winter bird usage
either positively or negatively and thus identify the optimal field management type and
strategies for farmland bird conservation.
4. Methodology
4.1 Site Selection
The location for the project was the townlands of Stamullen, Gormanston and Julianstown Co.
Meath, in the mid-east region of Ireland, which straddles the border with North Co. Dublin.
This region is considered an area of intensive farming (Figure 2). The average farm size in the
Mid-east and Dublin region (which include east Meath) is 42 ha. with 23% classed as specialist
tillage farms, 7% classed as beef, 6% dairy, 8% classed as specialist sheep farms and the
remainder arable crops (CSO, 2012). Site selection efforts focused on obtaining representative
tillage (winter cereal and cereal stubble) and pasture fields with permission to access from
landowners.

20. 13
Figure 2 Study area in east Co. Meath, Ireland
In total, 10 fields were surveyed, comprising two improved grassland fields (F6, F7), one semi-
natural grassland field (F1), two over-wintered cereal stubble fields (F9, F11) and five winter
cereal fields (F2, F3, F4, F8, F10). Table 4 outlines the general management of the field
surveyed, their geographic location and their allocated field number.

21. 14
Table 4 Surveyed fields and general management
General
Field Type
No. of
Fields
Winter
Management
livestock
Density
General Management Field
No.
Field GPS (SW
corner)
Kept as pature
for grazing but
not grazed over
winter
0 Intensively managed
mainly rye-grass sward
used for summer
grazing of cattle.
Periocically over
seeded.High fertilizer
inputs.
F6 53°38'49.1"N
6°16'0.06"W
Kept as pature
for grazing but
not grazed over
winter
0 Intensively managed
mainly rye-grass sward
used for summer
grazing of cattle.
Periocically over
seeded.High fertilizer
inputs. Includes area
wet grassland(GS4) in
lowest portion of the
field which is fence off
from grazing cattle and
not fertilized.
F7 53°39'02.9"N
6°15'58.2"W
1 Periodically
grazed by sheep
and horses
120
sheep,
5 horses
Low input permanent
pasture (20years+)
grazed year round by
sheep and horses.
F1 53°37'31.9"N
6°16'40.2"W
Autumn sown
wheat or barley
N/A Rotational crops of
cereal, Potatos.
F2 53°38'32.8"N
6°17'01.5"W
Autumn sown
wheat or barley
N/A Rotational crops of
cereal and Potatos.
F3 53°37'21.2"N
6°16'33.8"W
Autumn sown
wheat or barley
N/A Rotational crops of
cereal, Potatos, maize
and onions.
F4 53°37'44.0"N
6°12'17.2"W
Autumn sown
wheat or barley
N/A Rotational crops of
cereal, Potatos, maize
onions and ornamental
bulbs(Narcissus) and
cut flowers.
F8 53°38'49.8"N
6°15'40.9"W
Autumn sown
wheat or barley
N/A Rotational crops of
cereal and Potatos.
F10 53°37'22.9"N
6°17'6.8"W
Stubble N/A Rotational crops of
cereal, Potatos, maize,
onions and ornamental
bulbs(Narcissus) and
cut flowers.
F9 53°39'0.6"N
6°15'37.3"W
Stubble N/A Rotational crops of
cereal, Potatos, maize,
onions and ornamental
bulbs(Narcissus) and
cut flowers.
F11 53°37'21.4"N
6°17'22.9"W
Non Crop 1 Fallow N/A Formally in Glas
scheme(2018).
Ordinarily rotational
crops.
F5 53°38'0.4"N
6°15'1.5"W
Field Crop
No crop
Improved
Grassland
Grassland 2
Winter cereal
Over
wintered
cereal
stubble
Cereal
Semi Natural
Grassland
5
2

22. 15
A non-crop field (F5) was initially surveyed as it was considered to be of such a similar habitat
type to cereal stubble, that it could supplement the general deficiency of this habitat type. No
other stubble fields were present on any of the farmsteads. It was decided subsequently however
not to use the data from this field as it was deemed post field survey to be too dissimilar to the
field types in the study and generally unrepresentative of the general stock of field habitat types
in the region. Primary also in the reasons for exclusion were, its close proximity to the M1
motorway (which generated significant road noise), it was bordered on one side by the Delvin
River which represented a significant habitat change not present in any other fields and its field
layer largely consisting of bare ground with no significant vegetation except where it joined
with the riparian zone of the river.
The total study area of the 10 fields comprised of 71.9 ha., with pasture representing 14.1 ha.,
winter cereal 38.6 ha. and cereal stubble 19.2 ha. The pasture fields had a mean area of 4.7 ha.,
winter cereal 7.7 ha. and cereal stubble 9.6 ha. The fields were bordered by a mixture of treelines
(WL2), low-cut and unmanaged hedgerows (WL1) and linear woodland, which is in line with
the wider landscape.
No two survey sites were located directly adjacent to each other and even in cases where they
were in close proximity, there were separated by a landscape feature such as a road, farm track
or a linear woodland.
4.2 Timing of Field Survey Work
Field work commenced on the 16th
November 2018 and was completed by 2nd February 2019.
53 hours of field surveys were logged in total, comprising of 28 hours for bird surveys, 17 hours
of boundary appraisals surveys and 8 hours of field layer surveys. The timing of the bird survey
field work was broadly intended to coincide with the period when farm activity would be at it
quietest and any farm operations would be discreet and less likely to disturb natural bird

23. 16
activity. Similarly, Autumn migration was deemed to have ended by the start of the bird surveys
and most birds would be regarded as having arrived at their wintering quarters and therefore
representative of the general over wintering assemblages. This would help to ensure that any
fluctuations in bird assemblages were not likely to be as a result of farm activity or birds still
migrating. No farm activities were recorded in the field surveyed or the adjacent fields, at the
time of surveying. Additionally, field conditions were considered to be relatively stable during
this time, or as much as could be predicted, given that harvesting of cereals and sowing of
winter tillage would be complete and cattle would be moved off the land for wintering. In the
same way, bird surveys where intentionally completed by early February to avoid any changes
in field conditions such as ‘spraying off’(the application of herbicide to desiccate weed or cereal
re-growth) or ploughing of stubble fields which would considerably change the habitat
conditions and cause disturbance to any birds present. Likewise, any early turning out of cattle
onto grasslands would also be avoided. The surveys were also timed to be completed before
birds begin their exodus to their summer quarters to avoid recording reduced wintering bird
usage of the sites resulting from spring migration. Departure time will vary for different species
but can be as early as late January or early February.
4.3 Collection of Winter Bird Data
Amongst the requirements for carrying out the bird surveys was a pair of 8x42 field binocular
for bird identification and counting, a waterproof clip board and data recording sheets, a GPS
handheld device (Garmin Oregon 450t) for identifying field location points and accurate
mapping of bird locations. A mobile phone was used for the google maps app and for recording
the start and end times of survey work. The Met Eireann app was also used to aid in accurate
recording of weather conditions. Finally, a Nikon Digital SLR camera provided a visual record
of each field and all its boundaries and features.

24. 17
Each of the fields was surveyed on three occasions for bird assemblages using a standardised
procedure (Perkins, 2000; Field, 2011). A discrete approach to each field was considered
important to avoid bird disturbance or movement of birds to adjacent fields. This assured
accurate recording of birds and their usage of each field space. For this reason, fields were
approached, where possible, from a point of concealment and all obvious birds present
particularly on the internal field space, were recorded before entering. A google maps print out
of the field was used to record this with a position spot marked for each bird’s estimated location
on the map. Where flocks or small grouping occurred, the approximate centre of the group was
taken as the location. If a bird species such as black headed gull Larus ridibundus, was
considered distributed relatively evenly across the entire field, no location point was recorded
but an observation note was made to that effect. Following on from this, field boundaries were
walked. A constant distance of circa three metres from the boundary line was maintained. In
most cases, the field boundaries consisted of hedgerows but occasionally they were wire fences
and very occasionally walls. Where the boundary was a hedgerow, the three metre distance was
measured from the hedges most protruding point into the field. Field (2011) recommended a
distance of five metres from the boundary while others recommended a distance of as little as
1.5 metres (McMahon et al., 2013). The three metre distance however, was considered optimal
to ensure that all birds present were recorded but also that any birds further along the boundary
which were likely to be disturbed as the walk progressed, did not go unrecorded. A closer
proximity walk to a boundary hedge, would have detected any adjacent birds too but birds
present further down the boundary hedge and potentially out of the view line of the surveyor,
may well have evaded detection as they departed from the field. Conversely, walking at an
increased distance from the hedgerow boundary was considered likely to have made the
surveyor too perceptible not only to birds in the adjacent hedgerow boundaries but also to birds
in the other boundaries and the field space in general. The speed of walking depended on the

25. 18
ease of identification either by sight or call and on the number of birds present, however a
standard speed of about 2 km per hour was observed when possible as in line with previous
similar studies (Bibby et al., 2000; McMahon et al., 2013). All individual birds were identified,
numbers recorded, activity such as foraging or resting noted and locations logged using GPS
coordinates. Field transects at approximately 50 metre apart (walking along the longest axis)
were also walked to ensure all birds not readily visible from the boundary walk were flushed
and recorded. The combination of approach observations and the standardised boundary walks
and transects walks, ensured a good cross-sectional capture of all field habitats including
hedgerows and field margins as well as open grassland, tillage and stubble areas.
Other data recorded included weather conditions such as wind speed and direction,
precipitation, temperature and general conditions such as mild, cool or cold. In all cases,
surveying was not carried out if weather conditions were considered disadvantageous for the
observer to record accurately or were conditions were likely to effect bird activity or presence.
Surveying during precipitation and were wind speed was above force 4 on the Beaufort Scale,
was always avoided. These criteria would be considered integral to bird census recording
techniques (Bibby et al., 2000). In line with the majority of surveys (Barnett, 2004), birds flying
overhead were only recorded if they subsequently landed in the field or as in the case with
raptor species, if they were actively hunting in the field space’ otherwise there would be
uncertainty as to whether they were using the field or just transiting to an adjacent field.
Time of day for surveying was standardised to be carried out at least two hours after sunrise
and at least two hours before sunset. The reasoning behind this was to ensure, as much as is
possible, that all recorded birds were actively using the field for foraging and not just journeying
to or from roosting sites. In all cases this resulted in bird surveys commencing after 10.30am
and finishing before 2.30pm.

26. 19
To avoid the possibility of disturbed birds being double counted elsewhere in the field space,
careful observation was made to determine where flushed birds subsequently landed. Where
the counts of birds, in particular those using the internal open field space, was undetermined,
for example where there might have been several groupings of birds moving around the field,
an earnest attempt was generally made to count all these birds at one instance. This was often
observed to be the case with easily spooked species such as skylark Alauda arvensis or some
finch species. These species can periodically form large in-flight flocks of single species
coalescences, making it relatively easy to clarify exact numbers. Where birds were observed
to have left a field, particularly flocking birds, and were there was a possibility that they had
moved to other fields that also comprised part of the survey sites, no subsequent surveys were
carried out on these other fields on the same day. This unequivocally ensures avoidance of
double counting of species at other sites.
4.3.1 Bird Functional Feeding Groups
Although many bird species feed on a wide variety of food items of both a plant and animal
nature, most will show a preference for one type or the other and some will show a distinct
preference depending on the time of year. Segregating the various bird species into a list of
functional feeding groups was carried out. McMahon (2013) defines 5 bird groups based on
their diet preferences; farm indicator (seed feeders, graminivores), omnivores (crows),
Thrushes and Seed feeders and graminivores. Just four categories were defined in this study.
This may help to discern why a particular species might be more inclined to use one field or
field management type over another. For the purpose of classification in this study, only the
likely food items taken in the winter was used to categorise each species. Primary diet
categorisation was established by consulting Dempsey & O'Cleary (1993) and also personal
observation. The four categories identified are described as follows:
Grainiferous: Bird that feed largely on seeds, including cereal grain and weed seeds.

27. 20
Insectivorous: Bird that feed almost exclusively on insects. May also take small quantities of
seed.
Generalists: Bird that show no distinct preference for plant or animal-based food items. Items
might include slugs, snails and soil invertebrates as well as berries and seeds and even grazing
on leaves or consuming flower or leaf buds may complement their diet.
Raptors: Bird that feed on larger prey items such as rabbits, mice, rats, shrews, frogs and other
birds. Some may also feed on larger insects such as worms and beetles. Generally, consists of
birds of prey but grey heron Ardea cinerea is also included in this category.
4.4 Collecting of Habitat Data
In order to determine how the ecological quality of the field boundaries and the crop type in the
field (i.e. pasture or winter cereal, cereal stubble) influenced bird species richness, abundance
and distribution, field boundary appraisals and field layer evaluations were carried out. There
were no alterations (e.g. hedge cutting) to the field boundaries or the field layer (e.g. spraying,
cutting, ploughing) during the duration of the bird surveys or the habitat appraisals. Again, a
waterproof clip board and data recording sheets were utilising as well as a GPS device for
recording start and end points for boundary sampling and transect point for field layer
evaluations. A steel measuring tape was used for recording boundary features such as width of
hedgerow and field margins as well as field data such as height of vegetation.
4.4.1 Field Boundary Appraisals
The field boundary appraisal survey comprised of two procedures, the assessment of the
boundary characteristics and the evaluation of the woody species present. These surveys were
carried out consecutively, commencing on 17th
November 2018 and were concluded by 28th
January 2019. Each site was visited once. All hedgerows boundaries were assessed using the
field boundary evaluation system developed by Foulkes & Murray (2005) and subsequently

28. 21
used in their hedgerows surveys of Roscommon, Offaly and Laois. A representative 30-metre
sample strip was evaluated for every 100 metres of boundary and the start and end points of
each sample were recorded using GPS. This would ensure the accurate repeatability of any
future studies. Surveying generally began in the corner of a field or otherwise where two
boundaries met. The boundary appraisal field survey sheet was broadly based on modified
system of recording produced by Foulkes & Murray (2005) which consisted of 4 broad
categorisations; context, structure condition and management. Boundary details recorded
included boundary type, Fossitt class, condition, height, width and gappiness of hedge, field
margin width, presence and age of trees, fruiting evidence and apparent management methods.
Additionally, some basic land use information was also recorded such as field type and adjacent
land use, for instance pasture, crop type, scrub, woodland, residential, road or farm track etc.
To be able to fully evaluate the ecological significance of field boundaries, the data recorded
was subsequently collated using the Field Boundary Evaluation and grading system (FBEGS)
Developed by Collier and Feehan (2003), as an Irish alternative to the previously developed
British hedgerow scoring system, the Hedgerow Evaluation Grading System (HEGS)
(Clements & Tofts, 1992). Both the FBEGS, HEGS and the Foulkes and Murray (op. cit.)
methodology having many crossover components of assessment which allowed for the use of
the hedgerow appraisal data collected, to be interpreted successfully and provided with an
ecological score value in line with the FBEGS. The main categories of the FBEGS are boundary
structure, associated features of the boundary, boundary connectivity boundary diversity and
overall boundary type. Under these categories, each of the attributes of the hedgerow and/or
boundary and the associated adjacent land was assigned a score of between 1 and 5, which
allowed for an accumulated maximum scoring of between 7 and 30 per category. Some of the
attributes in the FBEGS where not included in the assessment for instance a score for the
presence of dry-stone walls, a score for non-native woody shrubs, a score for orientation of the

29. 22
boundary to the prevailing wind and a score for angle of the boundary to the slope. None of
these attributes were recorded during the survey and at any rate where either not present or were
not considered important in terms of evaluation for bird diversity. Table 5 below outlines the
score and grading system for hedgerow field boundaries as defined by Collier and Feehan
(2003).
Table 5 FBEGS scores and grades
FBEGS score Grade
≤19 Low
20-29 Poor
30-39 Good
40-49 High
≥50 Very High
The woody species boundary assessment, apart from identifying the species, also documented
the relative abundance level of each species present using the DAFOR Scale (Table 6). The
Dafor scale is a visual technique of measuring the relative abundance or frequency of
occurrence of a species in a given area. Each woody species was assigned a Dafor value which
indicates how common or rare it is but only in the context of that particular sample and not in
general. The presence of all the species in a sample was recorded first before a Dafor values
were assigned to each. This ensured that the entire sample was being taken into account when
allocating a value.

30. 23
Table 6 DAFOR Scale
DAFOR Scale
Value Description Meaning
D Dominant Comprises most of the
sample
A Abundant Very frequent but not
dominant
F frequent Frequently seen
O Occasional Seen but not frequently
R Rare Hardly ever seen
Finally, a photographic record of each hedgerow boundaries was taken.
4.4.2 Field Layer Evaluation
Broad classifications of the crop type were made using Fossitt (2000), i.e. tillage (winter cereal,
cereal stubble) and pasture (improved and semi-improved). However, additional field layer
evaluation was considered valuable in understanding winter bird use of the fields. Bird
abundance may be influenced by the type of plant cover present. In winter, plants are more
challenging to identify to species level, and it was considered more robust to ascertain the cover
of plant categories (perennial rye grass, other grasses, forbs, moss, bare soil and cereal stubble,
cereal stubble regrowth) instead.
To assess cover of the broad vegetation categories, a ‘W’ transect was walked through each
field (Figure 3), staying 2m away from boundaries to avoid change in plant communities along
field margins. GPS co-ordinates were recorded along the transect line to ensure repeatability.
A single survey of each field was carried out between the 29th
January and the 8th
February
2019. A pre-defined intercept interval of six metres along the transect was decided upon which
provided approximately 100 points per 5 ha for point intercept survey (Goodall, 1952; Jonasson,
1988). At each point, a ‘pin’ (in this case a narrow 1 metre long bamboo cane) was lowered

31. 24
vertically down through the vegetation into the substrate and any vegetation or soil/stubble
which was pierced or touched by the pin was recorded as a ‘hit’. In most instances, a single
component was ‘hit’ at each intercept point but occasionally two components were recorded;
and no intercept point registered any more than two components. Essential for each of the point
intercept surveys was that, each site had to be located within a single plant community to ensure
that any variations where not as a result of a change in habitat. Calculation of vegetation
category cover was undertaken by totalling the ‘hits’ for each component (rye grass, forbs, bare
soil etc.) in a field, dividing this by the total number of hits for each walk, and multiplying by
100 (DEC 2009).
Figure 3 A 'W' transect walk for F3, a winter cereal field

32. 25
Vegetation structure is also considered valuable for birds and this was assessed by recording
the height at incremental bands (e.g. 25-50mm, 50-100mm etc.) along the ‘W’ transect. For
each field, five vegetation heights were recorded and amalgamated to give a mean vegetation
height for each field. This was carried out on a single visit to each site. A photographic record
of each site was also taken.
All the data recorded during the field surveys was transferred into a Microsoft Excel data file
for subsequent ease of statistical analysis.
4.4.3 Data Analysis Methodology
By way of definition, species richness was taken as the aggregated number of species recorded
using the fields over the three visits. i.e. the accumulation of species for each of the fields over
the entire survey period. There are several different approaches by which abundance can be
defined and utilised, and all have possible benefits and drawbacks. The mean count over the
three visits was considered, but this was disregarded in preference for maximum counts of birds
over the three visits, as this abundance variable was considered the most reliable indicator of
the value of each of the survey fields for wintering birds (Bibby et al., 1992).
4.4.4 Explanatory Variables
Explanatory variables or non-independent variables are factors that can change and be affected
by other variables in a study. Table 7 below contain the explanatory variables looked at in this
study to attempt to explain farm bird richness and abundance.
Table 7 List of explanatory variables utilised to explain richness & abundance
Explanatory variable Variable type Factors
Field area Continuous
Field type 3-level factor Pasture, winter cereal, stubble
Sward height ± S.D. Continuous
Bare ground % Continuous
Stubble cover % Continuous
Winter cereal cover % Continuous
Non-cereal cover (grasses/forbs) % Continuous
Hedgerow density Continuous

33. 26
Distance to occupied building Continuous
FBEGS score Discrete
Field area can influence the probability of bird usage particularly those that use the open field
space for foraging. Snipe, skylark, meadow pipit, corvid and gull species all show preference
for larger fields. The three field management types provide the fundamental factors of variance
for this study and are the likely to be the factor of most influence due to the considerable
habitation variations they provide. Sward height can impact usage in two ways short swards are
more suited to smaller bird who can access the ground more easily, longer swards are more
suited to species that prefer a level of concealment when foraging or who’s stature can allow
them to take advantage despite the reduced accessibility. Percentage of bare ground may be a
factor for species that access food that occupies or is available on the surface or near surface of
soil such as certain soil invertebrates and grain. Stubble cover as with sward height can
influence the accessibility of the field layer. Very dense stubble may not suit species that utilised
the field surface but prefer to be able to monitor their surrounding for potential attacks from
predatory species. Winter cereal cover as with the proportion of bare ground, can influence the
obtainability of soil food items as once cover has attained a certain level of establishment
accessibility may be a problem. Higher Grass/forb cover will increase the heterogeneity of a
field and likely also increase the richness of food items available. An increase in grass and forb
species will contribute to a higher and more diverse seed bank availability. It is probable also
that there would be a corresponding increase in invertebrates that feed on these divergent forbs
and grasses. This scenario is most likely in pasture fields particularly semi natural grassland
fields under long term grass cover. Hedgerow density expressed as km/ha., is an indication of
how common hedgerows are in a field of a certain size. Distance to occupied building may
explain the presence of certain bird species who associate with household dwelling or
farmyards. Some resident species such as House sparrow, Passer domesticus, may take

34. 27
advantage of dwellings as potential nesting territory and the possibility of supplementary
feeding by homeowners particularly in winter. Farmyards that house livestock in winter are
frequently good source locations for spilt or open piles of feed grain, used for livestock. several
finch species, doves and pigeons are likely to be greatly associated with this readily available
food source. Finally, the FBEGS gives a precise numerical assessment of the potential of a
hedgerow, looking at all its structural characteristics (shape, size etc.) combined with shrub
species suitable for all bird species and also associated beneficial features (ditches, banks) for
bird diversity, expressed as an exact score or grade.
4.4.5 Statistical Analysis
Total bird abundance, species richness and Shannon Index for bird species were calculated
separately for a) management type (pasture, winter cereal and cereal stubble) and for b) diet
(grainiferous, insectivorous, generalist and raptor).
Bird abundance, richness and the composite Shannon Index were tested for normality (Shapiro-
Wilk test) and homogeneity of variance (Levene statistic). Bird richness (p = 0.947) and
Shannon Index (p= 0.835) were normally distributed and did not significantly deviate from
homogeneity of variance (p = 0.473 and p = 0.422 respectively). After log10 transformation,
bird abundance was normally distributed (p = 0.969) and the test for homogeneity of variance
was met (p = 0.721). A one-way ANOVA was calculated to test for differences in bird richness,
abundance and Shannon Index in the three management types using Tukey’s post hoc test,
which requires equal variances for each of the groups.
Differences in the species richness of birds across the four functional feeding groups per
management type, was tested using the non-parametric Kruskal Wallis test, as data was non-
normal and deviated from homogeneity of variance after log10 transformation.

35. 28
The presence of birds of conservation interest was noted during the survey. A one-way ANOVA
was carried out on the species richness and abundance (sum of maximum abundance across the
three survey periods) of birds of conservation concern across the three management types to
assess if there were any significant differences. The Shapiro-Wilk test showed that richness was
normal (p = 0.177) and the homogeneity of variance (Levene statistic) was met (p = 0.762).
After log10 transformation of birds of conservation concern, abundance was normal (p = 0.805)
the homogeneity of variance (Levene statistic) was met (p = 0.725).
The Shannon Index has enjoyed persistent long-term use in studies of diversity among bird
populations (McMahon et al 2005, Feehan et al 2002, Parish 1995), despite that a small sample
size might influence the results (Magurran 2004). It considers the number of species (richness)
as well as the relative abundance (the number of individuals of each species in relation to other
species present) (Geographyfieldwork.com). This accounts for some species being rare and
others being common. The Shannon Index is expressed as:
H=-∑ 𝑝𝑖 𝑙𝑛𝑝𝑖
Given the small data set and low number of replicates in each management category, it was not
possible to undertake statistics such as generalised linear models. To understand the
relationships between variables, multiple correlations were run between the explanatory
variables and species richness, abundance and Shannon Index. The data was a mix of normal
and non-normal distribution (i.e. skewed), and therefore Spearman’s correlation coefficient was
selected (Gardener, 2012). Spearman’s correlation coefficient may give poor confidence
intervals for data sets of less than 10 (Kirk, 2007), and hence caution must be shown when
interpreting the resulting correlations. Spearman’s correlations were also tested between the
dietary classification of birds (functional feeding groups) and the explanatory variables.

36. 29
Multivariate analysis techniques were used to investigate the bird community data from the
three different management types. Analysis were carried out using PC Ord 7 (MJM software).
Data were first screened for outliers (±2 S.D. from the mean). Hierarchical agglomerative
cluster analysis was performed to define assemblages based on their similarities in species
composition. The Sorensen (Bray-Curtis) distance measure and flexible beta group linkage
method (beta = -0.25) were used in the cluster analysis. The Bray-Curtis distance was selected
as it has been shown to be sensitive to differences in the most abundant bird species and less
sensitive to infrequently encountered species (Pillsbury et al., 2001). Multi-response
permutation procedures (MRPP) with 1000 permutations was used to test the null hypothesis
of no difference between the resulting groups.
To assist with interpreting the cluster groups in relation to species abundances and with
explanatory variables, ordination was performed using non-metric multidimensional scaling
(NMS) and the Sorenson (Bray-Curtis) distance measure in PC-ORD’s “slow and thorough”
default setting. Directions and strengths of correlations for the most highly correlated
environmental variables as determined by the Spearman’s correlations were shown as vectors
overlaid as a biplot on the ordination graph. Transformation of count data before running NMS
is sometimes recommended by ecologists (McCune and Grace, 2002) to minimise the range
differences between counts, however, others disagree (e.g. O’Hara, 2010). However, given its
prevalence in studies, and widespread acceptance, transformation was utilised for the birds
count data. Prior to NMS ordination, the maximum bird abundance per field data were log (x +
1) transformed to reduce the influence of dominant taxa on the analysis. The Bray-Curtis
distance metric was employed because it is sensitive to differences in the most abundant species
and less sensitive to infrequently encountered species and is invariant to changes in units
(Pillsbury et al., 2011). This works well with the data collected, as some species were
encountered frequently, and others were less frequently detected. The final dimensionality of

37. 30
the ordination solution was determined by the scree test (Kruskal and Wish, 1978); the
dimension selected was at the point where moving to another dimension provided little
improvement in fit (as shown by the scree plot). As the final configuration can differ depending
on the initial configuration and the number of iterations, the NMS was run repeatedly and the
outcomes from the lowest stress solutions compared (McCune et al., 2002).
5. Results
The survey area totalled 72 ha. across the 3 management types. Pasture represented 14.1 ha.,
winter cereal 38.6 ha. and cereal stubble 19.2 ha. The pasture fields had a mean area of 4.7 ha.,
winter cereal 7.7 ha. and stubble 9.6 ha.
5.1 Bird Survey Results
A total of 47 bird species (see Appendix i) and 2,392 individuals were recorded over the entire
study area which comprised of 41 field boundaries (36 hedgerow boundaries) over 72 ha. (see
Appendix ii-iv for the full results of the bird field surveys). This would compare very favourably
with results from McMahon et al., (2005) which recorded 34 species and 1401 individuals
during its winter surveys of 40 field boundaries on 490 ha.
The only species to occur in all 10 fields was dunnock while just three species, blackbird, blue
tit and robin, occurred in 9 of the 10 fields. Ten species occurred in just a single field each
including, black tailed godwit, fieldfare, golden plover, grey heron, house sparrow, merlin,
moorhen, teal and tree sparrow. The full species list, the maximum abundance of each species
per field management type and the total bird species count per field management type is
presented in Table 8. The full list of species abundances and richness per individual field can
be found in Appendix v.

38. 31
Table 8 Bird species abundance and richness per field management type
Common Name Scientific Name
BTO
Code
Max.
abundance
Pasture
(F1, F6,
F7)
Max.
abundance
Winter
Cereal
(F2, F3,
F4, F8,
F10)
Max.
abundance
Cereal
Stubble
(F9, F11)
Blackbird Turdus merula B 4 16 14
Black-headed Gull Chroicocephalus ridibundus BH 4 111 0
Black-tailed Godwit Limosa limosa BW 0 22 0
Blue Tit Cyanistes caeruleus BT 6 2 4
Bullfinch Pyrrhula pyrrhula BF 4 8 1
Buzzard Buteo buteo BZ 1 3 1
Chaffinch Fringella coelebs CH 8 12 42
Collard Dove Streptopelia decaocto CD 2 0 60
Common Gull Larus canus CM 2 5 0
Dunnock Prunella modularis D 4 7 5
Fieldfare Turdus pilaris FF 0 7 0
Goldcrest Regulus regulus GC 2 2 1
Golden Plover Pluvialis apricaria GP 0 6 0
Goldfinch Carduelis carduelis GO 11 0 30
Great Tit Parus major GT 5 0 1
Greenfinch Carduelis chloris GR 2 5 0
Grey Heron Ardea cinerea H 0 1 0
Grey Wagtail Motacilla cinerea GL 0 1 1
Hooded Crow Corvus corone cornix HC 1 2 3
House Sparrow Passer domesticus HS 10 0 0
Jackdaw Corvus monedula JD 19 30 8
Jack Snipe Lymnocryptes minimus JS 0 0 1
Linnet Carduelis cannabina LI 2 30 45
Long tailed Tit Aegithalos caudatus LT 2 0 0
Magpie Pica pica MG 2 1 0
Meadow Pipit Anthus pratensis MP 0 5 33
Merlin Falco columbarius ML 0 0 1
Mistle Thrush Turdus viscivorus M 10 2 4
Moorhen Gallinula chloropus MH 2 0 0
Phesant Phasianus colchicus PH 0 1 9
Pied Wagtail Motacilla alba yarellii PW 1 2 1
Redwing Turdus iliacus RE 61 2 120
Reed Bunting Emberiza schoeniclus RB 1 0 6
Robin Erithacus rubecula R 3 4 1
Rook Corvus frugilegus RO 38 50 70
Skylark Alauda arvensis S 0 24 110
Snipe Gallinago gallinago SN 10 1 1

39. 32
Common Name Scientific Name
BTO
Code
Max.
abundance
Pasture
(F1, F6,
F7)
Max.
abundance
Winter
Cereal
(F2, F3,
F4, F8,
F10)
Max.
abundance
Cereal
Stubble
(F9, F11)
Song Thrush Turdus filomelos ST 8 2 30
Sparrowhawk Accipiter nisus SH 1 0 0
Starling Sturnus vulgaris SG 35 0 35
Stock Dove Columba oenas SD 1 0 2
Teal Anas crecca T 5 0 0
Tree Sparrow Passer montanus TS 0 0 12
Tree Creeper Certhia familiaris TC 0 0 1
Wood Pigeon Columba palumbus WP 20 3 9
Wren Troglodytes troglodytes WR 4 3 3
Yellowhammer Emberiza schoeniclus Y 1 6 23
Max. abundance of birds for all field types: 292 376 688
Total bird species richness for all field types: 34 31 35
Combined, the cereal stubble fields comprised the largest share of avian abundance at a
maximum abundance of 688 individual birds. Both pasture and winter cereal fields had lower
maximum abundances at 292 and 376 respectively. Of the two cereal stubble fields, F11
contained 512 individual birds, over ten times the number recorded of F8, a winter cereal field,
which recorded 44 individual birds. In fact, cereal stubble fields, despite there being only two
in this study, represented 47.5% of the total bird abundance. Per hectare of each of the field
management types, pasture fields had maximum of 26.5 ±13.1 individual birds, winter cereal
had 12.8 ±7.8 birds and cereal stubble had 40.9 ±21.5 birds.
Average bird abundances across all field types for the survey period are presented in Figure 4
below. Stubble fields supported on average 391± 170 individual birds, winter cereal at just over
a quarter of that at 98 ± 39 and pasture fields supporting 124 ± 56 individual birds, about one
third that of stubble fields.

40. 33
Figure 4 Average bird abundance per field management type
To give greater insight into the bird abundances, Figure 5 presents the average bird abundances
per hectare for each of the field management types, and it is clear that cereal stubble supports
higher abundances of birds compared to the other two management types.
Figure 5 Percentage bird species abundance per field management type (proportionally per hectare)
0
100
200
300
400
500
600
Pasture Winter Cereal Cereal stubble
NumberofindividualBirds
Field Management Type
33.1%
15.9%
51%
Pasture Winter cereal Cereal stubble

41. 34
Figure 6 below present the average species richness across all three management types over
the survey period.
Figure 6 Average bird species richness per field management type
The average species richness in cereal stubble was the highest at 25 ± 4.2 species, followed by
pasture at 22 ± 2 species and winter cereal trailing behind at almost half the value of stubble at
just 13 ± 6.5 species.
The maximum species richness results for each of the field management types showed greater
similarity, with cereal stubble only marginally better at 35 species, than either pasture or winter
cereal at 34 and 31 species respectively. Field F9, a cereal stubble field, recorded the highest
species richness at 28 species (see Appendix v). The lowest score for richness was F8, a winter
cereal field, at just 6 species. For the most part the pasture fields were relatively evenly matched
with each other for bird richness, although F1 had the highest richness at 24 species, most likely
reflective of its higher field layer heterogeneity.
0
5
10
15
20
25
30
35
Pasture Winter Cereal Cereal stubble
NumberofBirdSpecies
Field Management Type

42. 35
Fig. 7 below represents the four primary functional feeding groups of all farm birds present and
across all 3 field management types (see Appendix vi for the full list of birds in each of the
functional feeding groups).
Figure 7 Mean species abundance of functional feeding groups across all field types
It can be reasoned from Figure 7 that the majority of bird species in cereal stubble are generalist
in nature while grainiferous and insectivorous species are evenly represented. In pasture fields,
again generalists dominate with insectivorous species represented by marginally more than
grainiferous species. Winter cereal fields also confirm the predominance of generalists.
Interestingly they had marginally more insectivorous species than pasture and surprising
numbers of grainiferous species were at their lowest across all 3 field types, in winter cereal,
which might be explained by a low availability of dropped grain following ploughing and tilling
operations in the Autumn. Raptors are only represented by four species across all field types
but in general stubble fields seem to attract marginally more species.
0
2
4
6
8
10
12
14
16
Grainiferous Insectiferous Generalist Raptor
No.ofBirdSpecies
Functional Feeding Groups
Pasture (F1, F6, F7) Winter cereal (F2, F3, F4,F8, F10) Cereal stubble (F9, F11)

43. 36
Several bird species in this study are of conservation concern, both red and amber listed. Red-
list species are those that are globally threatened according to the criteria set down by the
International union for conservation of nature (IUCN, 2019). They are defined as those whose
population or range has declined rapidly in recent years; and those that have shown historical
declines with no discernible sign of recent recovery (BTO, 2019). Amber listed species are
defined as species with an unfavourable conservation status in Europe; those who have borne
a moderate population or range decline in recent years; those who have suffered a population
decline historically but who have made a substantial recent recovery; rare breeding species; and
those with localised populations of international importance. Of the 47 species in this study,
19.1% are amber listed. Yellowhammer Emberiza schoeniclus is the only red listed species.
Table 9 presents the full list of species of conservation concern in Ireland that were recorded
during this study.
Table 9 Birds of conservation concern that occurred in the field surveys
Amber listed species
% of
sites
they
occurred
in Red listed species
% of
sites
they
occurred
in
Teal Anas crecca 10 Yellowhammer Emberiza schoeniclus 50
Merlin Falco columbarius 10
Golden plover Pluvialis apricaria 10
Snipe Gallinago gallinago 30
Jack snipe Lymnocryptes minimus 10
Black tailed Godwit Limosa limosa 10
Black headed Gull Chroicocephalus
ridibundus 40
Common Gull Larus canus 20
Stock Dove Columba oenas 20
Skylark Alauda arvensis 30
Figure 8 presents the abundance levels per fields and per fields management type, for 4 of the
11 birds of conservation concern. Almost all the other species of conservation concern occurred

44. 37
in only one field and most on only one occasion apart from stock dove which occurred in two
fields, F6, a pasture field and F11, a stubble field and common gull which occurred in F1 a
pasture field and F2, a winter cereal field.
Figure 8 Max bird abundance per field and per field management type for five farm birds of conservation concern
0
2
4
6
8
10
12
F1 F2 F3 F4 F6 F7 F8 F9 F10 F11
Max.BirdAbundance
Field Number
0
2
4
6
8
10
12
Pasture Winter Cereal Cereal stubble
Max.BirdAbundance
Field Management Type
0
20
40
60
80
100
120
F1 F2 F3 F4 F6 F7 F8 F9 F10 F11
Max.BirdAbundance
Field Number
0
20
40
60
80
100
120
Pasture Winter Cereal Cereal stubble
Max.BirdAbundance
Field Management Type
0
20
40
60
80
100
120
F1 F2 F3 F4 F6 F7 F8 F9 F10 F11
Max.BirdAbundance
Field Number
0
50
100
150
Pasture Winter Cereal Cereal stubble
Max.BirdAbindance
Field Management Type
0
5
10
15
20
25
Pasture Winter Cereal Cereal stubble
Max.BirdAbundance
Field Management Type
0
5
10
15
20
25
F1 F2 F3 F4 F6 F7 F8 F9 F10 F11
Max.BirdAbundance
Field Number
snipe
yellowhammer
Black headed gull
skylark

45. 38
A One-way ANOVA carried out showed that species richness of birds of conservation concern
(p= 0.021, F = 7.000) was significantly different across the three field management types, but
abundances were not significantly different (p= 0.483, F= 0.784). Tukey’s post hoc test showed
that the species richness of winter cereal versus cereal stubble (p=0.018) was significantly
different, where winter cereal held higher species richness for species of conservation concern.
Snipe occurred in three fields. Single occurrences were recorded in F8, a winter cereal field,
and F9, a cereal stubble field, whilst 10 individuals were recorded in F7, a pasture field. Those
that occurred in F7 (Plate 1) were located in a fenced-off, wet low-lying area of the field where
dense rough grass predominated with some evidence of sedge growth. This area was also
adjacent to a broad waterfilled ditch although no snipe was recorded at or in this habit type.
Although the entire field was categorised as pasture, the area in the field were snipe was
recorded could be considered a habitat change and therefore most of this field not typical habitat
for the species. Snipe did not occur in any other part of this pasture field.
Jack snipe Lymnocryptes minimus, an uncommon amber listed species, also occurred in F9.
Although considered uncommon they can be easily overlooked due to their habit of remaining
motionless and only taking flight at the last second if disturbed (Sikora, 2005), so they are likely
an under recorded species. Its occurrence in the relatively dry habitat of a stubble field would
also be considered an unusual choice for the species who usually frequent grassy wetlands, bogs
or freshwater marshes (Dempsey and O’Clery, 1993). Moorhen Gallinula chloropus and teal
Anas crecca also occurred along the water filled boundary ditch of F7.
Skylark occurred most abundantly in the two stubble fields F9 and F11 with maximum counts
of 25 and 110 individuals respectively. Skylark also occurred in F8, a winter cereal field, with
a maximum recorded abundance of 24. No skylark occurred in any other cereal field or any of
the pasture fields.

46. 39
Black headed gull and common gull occurred most frequently in F3, a winter cereal field with
maximum abundances of 111 and 5 respectively. The only other field to record both species
was F1, a pasture field with maximums of 4 and 2 individuals recorded respectively. Black
headed gull also occurred in two other winter cereal fields, F2 where 3 individuals occurred and
F10 where 6 individuals occurred.
Plate 1 Wet area of Field F7 where snipe, moorhen and teal occurred
Yellowhammer (Plate 2) was almost universally associated with cereal stubble fields. A small
number of exceptions occurred. Single sightings occurred in F6 and F7 both pasture fields but
in both situations, they were within a relatively short flight distance from F9, a stubble field. A
single occurrence of 5 birds in a boundary hedgerow of F10 (a winter cereal field), can be
similarly explained due to there being a cereal stubble field (F11) on the opposing side of a
broad hedgerow of about 10 m wide at the point they were observed. In all cases where
Yellowhammer occurred outside of stubble fields, birds were observed perched in hedgerows,
a habit associated with rest or refuge for this ground foraging grainiferous species. No

47. 40
comparative records could be found for the fields associated with this study or in the near
locality. The only verifiable substantive records for this red listed species were found for Platin,
Duleek Co. Meath (Irishbirding.com) which is within 9.5 km of F11, the field which recorded
the highest Yellowhammer numbers. The Duleek records have historically shown a generally
upward trajectory from a record of 34 in February 2012 to a high of 70 in February 2018 and
as far as can be verified, all reports were from over wintered stubble fields.
Plate 2 Right - Yellowhammer on stubble field; Left Bullfinch a shy inhabitant of unmanaged hedgerows (Source: Caschera
V.)
Another species of note, although not of conservation concern, was bullfinch (plate 2) which
occurred in F1, F2 and F6, the three fields with the highest hedgerow density. Their occurrence
seems to be unrelated to the nature of the field crop which is probably reflective of the fact that
they are almost exclusively a hedgerow inhabitant, shy in nature and are seldom seen in the
open Crocker, 1987)
5.2 Field Boundary Results
A total of 11.64 km of field boundary were surveyed of which 8.77 km consisted of hedgerow.
This gave an average overall hedgerow density of 0.12 km /ha. of farmland. No comparative
density could be found for Co. Meath in published in grey literature. The nearest geographic
figure is 5.83km/km sq. (0.0583km/ha.) for Fingal County Dublin (Fingal, 2007) although it

48. 41
should be noted that this figure takes into account the entire land area, urban, rural,
infrastructure etc. and a far larger sample size (2,600 ha.), so considerable difference is to be
expected when compared with the result in this study. Table 11 below outlines the primary
results of the field and boundary surveys (see Appendix vii for survey sheets from boundary
appraisals).
Table 10 Primary results of the field and boundary surveys across all management types.
Field Type
N (total
number
of
fields)
(Ha.)
Mean
area ±
SD*
(Km)
Mean total
perimeter
length ±
SD**
Mean
hedgerow
boundary
length ± SD
a
(Km/ha.)
Mean
hedgerow
density
Mean
other
perimeter
length ±
SD b
Pasture 3
4.68±
0.52 0.96± 0.04 0.92 ± 0.09 0.20 ±0.1
0.05 ±
0.08
Winter
Cereal 5
7.71
±3.14 1.22±0 .044 0.79 ± 0.14 0.12 ±0.06
0.36 ±
0.51
Winter
Stubble 2 9.6 ±0.87 1.33 ±0.17 1.04 ± 0.25 0.11 ±0.02
0.29 ±
0.08
a
= Hedgerow length is defined as length of hedgerow per field and not total boundary length per field.
Hedgerows are taken to include all hedgerows regardless of condition (long term unmanaged, heavily managed,
coppiced etc.) and includes continuous lines of trees except sporadically spaced trees (isolated trees along a
field boundary in excess of 20m apart).
b
= All field perimeter except hedgerow boundaries, including fence lines, walls and field perimeter with no
features.
The FBEGS score for each boundary in each field are presented in Appendix viii. Table 12
below summarises the scores for each field and each of the 3 field management types.
Table 11 FBEGS mean scores and standard deviations for all fields and field management types
Field
Type
Field Number Mean FBEGS score
per field
Grade
Mean FBEGS
score per field
type ± SD.c
Pasture
F1 27.2 poor
25.8 ± 6.6F6 31.5 Good
F7 18.6 Low
Winter
Cereal
F2 33.8 Good
24.9 ± 11.5
F3 20.7 Poor
F4 19.6 Poor
F8 11 Low

49. 42
F10 39.5 Good
Cereal
Stubble
F9 20.3 Poor
26.7 ± 9.0
F11 33 Good
Note: c
= Average of all individual field boundaries per field, then averaged per field type.
Cereal stubble fields on average scored best using the FBEGS but the relatively high SD.
(standard deviation) of 9 would suggest that that might not be the outcome for this field type in
general and that a larger sample size than 2 fields, might have yielded different results. Pasture
field ranked marginally lower but also had the lowest SD. of just 6.6, which might suggest that
there is more uniformity in the condition of hedgerows in pasture fields. Nevertheless, F7 a
pasture field scored the second lowest at 18.6, using the FBEGS. Winter cereal fields scored
the lowest overall but also had the highest SD. of 11.5. It should be noted that the two highest
scoring individual fields, F2 and F10 (Plate 3), with FBEGS of 39.5, were nevertheless winter
cereal and that conversely F8 (Plate 4), another winter cereal field, was the lowest scoring
individual field with a FBEGS of 11.
Plate 3 F10, a winter cereal field which had the highest FBEGS score of 39.5.

50. 43
Plate 4 F8, a winter cereal field which had the lowest FBEGS score of 11.
Table 13 below summarises the results of the woody species survey along the boundaries for
each field surveyed.
Table 12 Mean woody species richness in field boundaries of the three management types surveyed
Field
Number
Field management
type
Mean woody species
richness ± SD.
F1 Pasture 5.7 ± 1.4
F6 Pasture 7 ± 0.8
F7 Pasture 3.5 ± 1.7
F2 Winter cereal 7.4 ± 2.1
F3 Winter cereal 5.6 ± 3.3
F4 Winter cereal 6.3 ±1.2
F8 Winter cereal 3 ± 2.0
F10 Winter cereal 6.3 ± 1.5
F9 Cereal stubble 1.6 ± 0.9
F11 Cereal stubble 8 ± 1.0
F11 had the richest hedgerow boundaries with a mean of 8 ± 1.0 species followed closely by
F2 at 7.4 ± 2.1 species. The standard deviation of 1 in F11 would suggest that all the hedgerow
boundaries were relatively uniformly rich in species. F9 had the least rich hedgerow boundaries
for woody species at just 1.6 ± 0.9 species and the low SD. would suggest that this was the case
for the entirety of its hedgerow boundary. F8 was the next sparsest for species at 3 ± 2.0. F3
was the field with the highest SD. of 3.3 and a mean species richness of 5.6 (Plate 5). These

51. 44
results reflect the wide variance in the condition of its hedges which ranged from ‘dense’
species rich to ‘open’ species poor. The full woody species result for all hedgerow boundaries
can be found in Appendix ix.
Plate 5 F3, field with the highest boundary hedgerow standard deviation for woody species richness
5.3 Field Layer Results
Table 14 below set out the average sward heights and percentage cover of both individual fields
and for all the field management types. ( see Appendix x for full field layer survey results).
Table 13 Mean sward height and bare ground cover per field and per field management type
Field
Management
Type
Field
No.
Mean Sward
Height Per
Fielda
Bare
ground
% cover
Per
Field
Mean Sward
Height Per Field
Management
Typea
Mean Bare ground
% Cover Per Field
Management Type
Pasture
F1 2.6 0
3.9 1.7F6 4.4 4
F7 4.6 1
Winter
Cereal
F2 3.2 86
3 72.2
F3 3.8 62
F4 2 91
F8 3 42
F10 3 80
Cereal
Stubble
F9 5.8 16
5.3 10.5
F11 4.8 5
a
= >1<2=25-50mm, >2<3=51-75mm, >3<4=76-100mm, >4<5=101-150mm, >5<6=151-200mm,
>6=>201mm.

52. 45
Sward height (including stubble) was highest in cereal stubble fields at a mean of 150-200mm
followed by pasture at a mean height of 76-100mm. It should be noted however that mean sward
height for pasture was almost in the next highest band of 101-150mm. Winter cereal had the
lowest sward height at a mean of 76-100mm and could have easily been in the next lowest
height band, 51-75mm. Closer examination of individual field sward heights, shows that of the
3 pasture fields, F6 and F7 (short rotation rye grass pastures), had a mean height of 101-150mm
while F1, a semi natural permanent pasture, had a mean height of 51-75mm. Sward height in
winter cereal was relatively uniform at 76-100mm with the exception of F4 which had a lower
sward height of 51-75mm. Cereal stubble as mentioned had the highest sward height but F9 in
particular stood out with a sward height of 151-200mm. Percentage bare ground cover was low
across all the pasture fields but lowest in F1, a semi natural field of permanent pasture which
did not register any bare ground. Amongst winter cereal fields, F8 followed by F3 had the
lowest bare ground percentage cover at 42% and 62% respectively. All other winter cereal fields
had bare ground cover in excess of 80% with F4 the highest at 91%. Overall, winter cereal had
the highest bare ground percentage cover at 72.2%. Bare ground cover for cereal stubble was
low at a mean of 10.5% but particularly so for F11 at just 5%.
5.4 Testing for Significance between Management Types and Abundance, Species
Richness and Shannon Index
The One-way ANOVA showed that species richness (p= 0.014, F = 8.389) and abundance
(p=0.044, F=5.057) were significantly different between the management types (Table 15). The
Shannon Index was not significantly different (p=0.406).
Tukey’s post hoc test shows that the species richness of winter cereal versus pasture fields
(p=0.039) and winter cereal fields versus stubble fields (p=0.023) were significantly different
from each other. However, there was no significant difference in bird richness in pasture versus

53. 46
stubble fields (p=0.764). Tukey’s post hoc test showed that significant difference in winter bird
abundances were present between winter cereal and stubble fields (p=0.045).
Table 14 One-way ANOVA with Tukey’s post hoc test comparing species richness & abundance with pasture, winter cereal
and stubble
Winter Cereal v Pasture Winter Cereal v Stubble Pasture v Stubble
Species richness 0.039* 0.023* 0.764
Abundance 0.996 0.045* 0.069
*p<0.05; p<0.01
A Kruskal-Wallis H test showed that there was a statistically significant difference in the
species richness of generalist bird species χ2(2) = 6.290, p = 0.043. Dunn’s pairwise tests were
carried out for the three field management types. There was evidence (p <0.026, and 0.078
when adjusted using the Bonferroni correction) of a difference between the species richness of
generalists in the pasture compared to the stubble fields. There was no evidence of a difference
between the other pairs.
Table 16 shows the Kruskal Wallis H Test testing differences between species richness
functional feeding groups in the three field management types.
Table 15 Kruskal Wallis H test, Testing differences between species richness across functional feeding groups
Functional Feeding
Groups
Chi-square Significance
Insectivorous 1.641 0.440
Generalists 6.920 0.043*
Raptors 1.493 0.474
Grainiferous 5.939 0.051
*p=0.05
Table 17 below presents all the significant correlations between species richness, species
abundance and Shannon’s index and the key explanatory variables.

54. 47
Table 16 Spearman's rank correlation coefficients of species richness, abundance and Shannon’s Index with explanatory
variables (n=10)
Log
Abundance
Shann
on
Index
Species
Richness
Area
(ha)
FBEGS
score
Sward
height
(cm)
Non-
cereal
cover (%)
Winter
cereal
cover (%)
Bare
ground
cover (%)
Stubble
cover
(%)
Species Richness r=0.71
7*, p=
0.020
r=0.814**
, p= 0.004
r=0.849*
*
p= 0.002
r=0.856*
*
p= 0.002
r=
0.675*,
p= 0.032
Species Log
Abundance
r=
0.688*,
p=
0.028
Shannon Index r=
0.717*,
p=0.020
Hedge Density r= -
0.893**,
p= .001
Sward Height r=0 .695*,
p=0.026
r=-
0.817**,
p=0.004
r=-
0.821**,
p=0.004
Non-Cereal
Cover
r=-
0.844**,
p=0.002
r=-
0.816**,
p=0.004
Winter Cereal
Cover
r=0.718*,
p=0.019
Distance to
Dwelling/yards
r= -
0.622,
p= 0.055
*p=0.05 **p=0.01
There was a high positive correlation between bird species richness and sward height (r= 0.814,
p= 0.004). Similarly, there was a high correlation between non-cereal cover (i.e. grasses and
forb species) and bird species richness (r= 0.849, p= 0.002). Bird species richness was highly
negatively corelated with winter cereal cover (r= -0.856 p= 0.002) and similarly bird species
richness was also negatively associated with bare ground cover (r= -0.675, p= 0.032). There
was also a s positive correlation found between species abundance and stubble cover (r= 0.688,
p= 0.028). Correlations also existed between the explanatory variables. Hedgerow density was
negatively so, highly correlated with area of field (r=0.893, p= 0.001). Sward height was
positively correlated with non-cereal cover (r=0 .695, p=0.026) and negatively so highly
correlated for both winter cereal cover (r=-0.817, p=0.004) and bare ground cover (r=-0.821,
p=0.004). A high negative correlation also existed between non-cereal cover and winter cereal
cover (r=-0.844, p=0.002) and also non cereal cover and bare ground cover (r=-0.816, p=0.004).