2.
OWL'S FEATHERS by RUTH PHILLIPS
Have you ever really examined a bird's
primary, or wing feather? It is a miracle
of lightness and strength, being able to cope
with the strain of flight. You will see that
it has a central shaft, with a vane, or web,
on each side composed of barbs. These barbs
usually have barbules, or smaller barbs, on
each side of them. Those on top of the barbs
have tiny hooks to hold them to the bottom
barbules on the barbs above. This keeps the
feather together on the principle of a zip-
fastener. If it comes undone, under stress,
the bird can "zip it up" with its bill when
preening.
Feathers are adapted to suit the need
of each species of bird and are very specia-
lised in Owls. The barbules generally lie
flat in the same plane as the shaft, in
other birds'
primaries, but
many of the
barbules, on an
Owl's tail and
wing feathers,
turn at right
angles to the barbs, giving a texture like
velvet and allowing the air to filter through
silently. In addition, the tips of some of
the barbs on an Owl's first primary are bare
of barbules, giving the effect of a comb and
making for slow, silent flight.
The feathers on the facial disc are also
different. They are extra long and thin.
Those round the beak and eye are stiff with
few or no barbules, while those all over the
disc are smooth, flat and widest at the tips.