1.
Advanced Ornithology
by
Maryam Riasat
TYPES OF FEATHERS

2.
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

3.
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

4.
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

5.
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

6.
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

7.
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

8.
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

9.
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

10.
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

11.
 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

12.
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

13.
 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

14.
 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

15.
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