| Raptors,
like all living organisms, are a complex structure and to go into
them fully would take forever. Here we will briefly list the important
points only.
Breathing
The raptor like us has two lungs, but whereas ours both pull air
in and expel it out, a bird pulls air in at one end of the lungs
and expels it from the other, making it much more efficient. In
addition they have a series of air sacs which, while not actually
processing the gasses, aid the respiratory system while at the same
time providing a very efficient heat exchanger for cooling down,
as well as giving a degree of buoyancy.
Skeleton
The bones of all birds, while not exactly hollow, nevertheless contain
a lot of air, thus reducing the bird's overall bodyweight and more
easily facilitating flight. The birds themselves are not very big
- most of what you see is feather and a buzzard would make a hugely
disappointing Sunday roast.
Digestion
All diurnal raptors have a crop where food is temporarily stored
prior to sending down to the gut where it is processed. Once the
food has been digested, the indigestible parts such as fur, feather
and insect shells are formed into a pellet, or casting, and regurgitated
the next day. Raptors are in many respects creatures of habit and
it is often possible to find a heap of such pellets beneath a bird's
favourite casting perch.
Metabolism
Raptors operate at a much faster rate than we, with a heartbeat
of around 100 beats per minute at rest and up to 300 when stressed
or during high activity, and with a body temperature of around 41ºC
as opposed to our 37ºC
Feathers
There are many different types of feathers on a bird, all performing
different functions.
Flight
feathers which power and control flight, among Other
Things.
Covert or Contour feathers which help produce an
aerodynamic shape, among Other Things
Down which provides insulation, among Other
Things
Crines which are thin, hair-like feathers which
help dissipate dried blood.
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