Page 13 - Complete Birds of Britain and Europe (DK - RSPB)

ANATOMY

WING MARKINGS “wrist”
Look at the feather tracts on a bird when
perched and in flight. On some species
most feathers are visible on the closed tertials
wing. On others, such as this Gull-billed hidden in
Tern, the primaries and secondaries are flight
hidden: all we can see are the primary tips. “elbow”
A large area between the back and the
wingtips is formed by rounded, plain grey
feathers called the tertials. On some birds secondaries
now visible on
these are large and obvious but in flight, as spread wing
the wings straighten, they may slide out
of sight under the scapulars.Therefore OPEN AND CLOSED WINGS
what is a prominent feature at rest This Gull-billed Tern has very long,
may disappear in flight. tapered, pointed wings that reach
well beyond its tail when folded but
scapulars
extend to reveal the obvious “wrist”
(or carpal) joint and the elbow joint
closer to the body. Only the fore edge
of the inner half of the wing has any
full length of solid muscle; the rest is just feathers.
primary tertials wing coverts primaries revealed
tips cover half cover on open wing
of primaries secondaries
FEATHERS
FEET Feathers not only allow flight large tail feathers, are usually
The shape of the feet indicates the and keep a bird warm and dry, wider on one side than the other
lifestyle of a bird.For example,webbed but they also add a variety of to create the aerofoil shape that
feet or toes with broad lobes each side colour, pattern, and shape. Some gives a bird extra lift.They are
aid swimming,while feathered feet help develop purely for decoration, overlain at the base by smaller
prevent heat loss.There are variations, while others provide cryptic “coverts”.The feathers that
but below are four of the main shapes patterns to help the bird avoid smooth the shape of a bird’s
and details of the actions they enable. predators.The large, stiff quills body are the contour feathers,
that support a bird in the air, the while loose down feathers form
“flight feathers”, and the equally an insulating underlayer.

outer
web
inner
web
WALKING CLIMBING
The long hind claw is Two backward-facing
typical of small birds, toes and strong claws COMPLEX STRUCTURE
such as pipits, that run allow climbing birds to Feathers are amazingly complex.
or walk in grassy places. grip onto a branch. This close-up shows that the vanes
each side of the central
shaft “zip” together
with minute hooks
and barbs.

HUNTING SWIMMING shaft
Sharp, hooked claws Webbed feet provide
grasp live prey; a strong extra thrust under the
grip makes the hind water’s surface, which is DOWN FEATHER CONTOUR FEATHER PRIMARY COVERT TAIL FEATHER
claw a lethal weapon. ideal for swimming.

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