A
gpc1 gpc5 gpc10
gsc9 gsc5
C
pigeon
barn owl
gpc9
gpc10
gsc5 gpc1 gpc5
gpc9
p10
gsc10
br
p10
p9
br
hr
p
h
hr
p
p
p bb
p9
s8
B
s4
outer vane
p1
fringes
rachis
s8
90%
length of fringe
80%
70%
60%
depth of vane
50%
length of barbs
40%
20%
10%
0%
calamus
length of
serration/fringe
100%
30%
plumulaceous
barbs
bs
bs
p1
s4
inner vane
serration/
fringes
vane
p5
p5
}
number of
barbs per cm
angle between
barb and
rachis
D
number of radiates
per mm
length of
pennulum
length
of br
angle (radiate/
barb shaft)
length of
pennulum
length
of hr number of hooklets