3. Feathers fall into following broad categories based on
their structure and location on the bird’s body
Vaned feathers
o Contour feathers
o Wing feathers
o Tail feathers
Semiplume
Filoplume
Down
Bristle
4. Vaned feathers
The most conspicuous feathers are called vaned
feathers
They include the smaller contour feathers that
cover the body surface and the larger flight
feathers of the wings and tail
The smooth overlapping arrangement of vaned
feathers reduces air turbulence in flight
The tiny, flat contour feathers that cover a
penguin’s body create a smooth, almost scaly,
surface reduces friction during swimming
5. Wing feathers
The flight feathers of the
wing, called remiges are
large and stiff
pennnceous feathers
They primarily serve
aerodynamic functions
and have little importance
in insulation
Rows of smaller feathers,
called coverts, overlap the
bases of the remiges and
cover the gaps between
them to reduce air
turbulance
Coverts assists in flight
6. Primaries
The long shafts of the
outer (distal) remiges are
called as primaries
Primaries are attach to the
bones of the hand and the
second digit
These feathers provide
forward thrust on the
downstroke of the wing
during flight
Most birds have 10
primaries but the number
can variate from 1 to10
7. Secondaries
• The inner (proximal) flight feathers of the wing
are called as secondaries
• Secondaries are attach to the ulna wing bone
• Numbering vary from 6 to 19
• In some species, they have been modified for
display purposes, essential for courtship
8. Tail feathers
• The flight feathers of the
tail, called rectrices
• Rectrices are attach to the
fused caudal vertebrae,
or pygostyle
• The usual 12 rectrices
function primarily in
steering and braking
during flight
• Numbering vary from 12
to 24
9. Rectrices vary from thin
and flexible, like those in
the display tail feathers of
some hummingbirds to
stiff rods, like those of the
bracing tail feathers of
woodpeckers
10. Down
Unlike firm-vaned feathers, down (plumulaceous)
feathers are soft and fluffy i.e. feathers of chicks
Down feathers provide excellent natural thermal
insulation
A down feather typically lacks a rachis except few birds
i.e. waterfowl
Down feathers also lack hooked barbules
On most birds, flexible plumulaceous barbs and
barbules extend directly and loosely from the basal
calamus
Downy barbules entangle loosely, trapping air in an
insulating layer next to the skin
11.
12. Semiplume
Semiplumes are intermediate in structure
between down and contour feathers
They enhance insulation, fill out the
aerodynamic contours of body plumage, and
serve as courtship ornaments
A semiplume has a large rachis with loose
plumulaceous vanes
Some are close to down in structure, whereas
others more closely resemble contour feathers
13. Semiplumes are located
between the contour
feathers and are usually
hidden from view at the
edges of the contour
feather tracts
Semiplumes are
distinguished from
down feathers by the
length of their rachises,
which are always longer
than the longest barb
14.
15. Filoplume
Filoplumes are very small hairlike feathers
Contain a rachis and only a few sparse barbs at
the tip
A fine shaft, or rachis, thickens distally, ending in
a terminal tuft of one to six short barbs with
barbules
Distributed inconspicuously throughout the
plumage, they are most numerous near
mechanically active or movable feathers
Each flight feather may have from 8 to 12
filoplumes
16. They extend beyond the contour feathers of
songbirds, particularly on the back of the neck, a
region called the nape
Filoplumes provide sensory information
pertaining to temperature, wind speed, and
feather movements needed for birds to fly
efficiently
Disturbance of a filoplume’s enlarged tip is
magnified and transmitted by the long, thin shaft
to sensory corpuscles at its base, which then
signal the muscles at the base to adjust the
feather’s position
17.
18. Filoplumes associated with the flight feathers
aid aerodynamic adjustments
Filoplumes association with contour feathers
help to monitor airspeed
Filophimes are absent in penguins and in
flightless birds such as ostriches
19.
20. Bristle
Bristles are specialized feathers with both sensory
and protective functions
Bristles are simplified feathers that consist only of
a stiff, tapered rachis with a few basal barbs
Bristles are found almost exclusively on the heads
of birds
They can located around the eyes and beak of a
birds
Most aerial insect eating birds have bristles and
around their mouths
Bristle feathers are also believed to be sensory in
nature