Poster Presentation- Post-Fledging Behavior of Western Screech-Owls in Southern Idaho
1. Post-Fledging Behavior of Western Screech-Owls
in Southern Idaho
Alfredo Gonzalez1,2,3, Skyler Swiecki1,2, and James Belthoff1,2
1REU Program in Raptor Research at Boise State University, Boise, ID 2Department of Biological Sciences and Raptor Research Center, Boise State University, Boise, ID 3Florida State University, Tallahassee, FL
Contact: ag13j@my.fsu.edu
Background and Objectives Results-Dispersion
Study Area and Methods
We studied 4 families of Western Screech-Owls in the Morley Nelson
Snake River Birds of Prey National Conservation Area from May – July
2016.
Results-Roosting Behavior
Fig.1: Frequency (%) of
roost types during post-
fledging period (all
families combined).
Roosts in thickets are
common later in PF
period.
Fig. 2: Relative height of
roosts (all families
combined).
Owls roosted relatively
low in trees.
Fig. 6: Frequency (%) of
owls roosting alone
during post-fledging
period.
Increased to 100% as
PF period progressed.
Home Range Isopleth Map
Fig. 3. Isopleth
home range for
owls at Cabin
site.
There are some
concentrated
areas of roosts.
Table 1: Tree Species used as Roosts during the
Post-Fledging Period Fig. 4: Distance of roost
sites from nests during
the post-fledging
period.
Distance varied by
family.
Fig. 5: Distance
between siblings
(families combined).
Generally greater as PF
period progressed.
• Radio-transmitters (VHF, 4.5g) were attached to
all nestlings in a family 1 week before fledging.
• Owls were located twice per week using a
handheld Yagi antenna and portable telemetry
receiver.
• Coordinates of roost locations were recorded.
Acknowledgements
This research was supported by National Science Foundation REU Site Award
(DBI: 1263167) to Boise State University, and by Boise State University's
Raptor Research Center, Department of Biological Sciences, College of Arts
and Sciences, and Division of Research. I also thank my fellow Raptor REU
students for help with fieldwork and BLM and CJ Strike WMA personnel for
logistical support.
Western Screech-Owls (Megascops kennicottii) are small, nocturnal
raptors found in woodlands of western North America. After fledging,
young must learn to fly and hunt before dispersing from natal areas, all
while avoiding predation. Our goal was to examine the roosting
behavior and movements of fledglings to help understand post-
fledging behavior in this poorly studied species of owl.
Objectives:
• Describe diurnal roosting behavior and
habitat use of radio-tagged fledglings.
• Characterize patterns of dispersion,
specifically distance from family members
and the nest.
• Quantify timing of dispersal from the natal
area.
• Examine trends in behavior as the post-
fledging period progresses and differences
in behavior among families of owls
occupying different sites.
• We characterized: roost type and height,
tree species and height, as well as
distance from siblings and the nest.
Summary and Implications
• The post-fledging period lasted approximately 8-10 weeks in Western
Screech-Owls before dispersal.
• Fledglings sought roosting cover primarily in trees.
• Roosting behavior of fledglings changed over time to include more thickets
and increasing independence from siblings.
• Distance from nest depended on available habitat
and varied among families.
• We now understand characteristics of brood
rearing habitat.
• Characterizing post-fledging roosting behavior of
Western Screech-Owls is important for future
research focused on factors that drive natal
dispersal in owls.
