Birds and Ear Physiology

name        Andy
status       educator
grade        other
location     MI

Question -   How do birds equalize inner ear pressure when
flying at high altitudes?
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Andy,

The fact is this subject is not completely understood, but it is
certainly interesting.  Some of this may be explained by the fact
that birds have extensive air sacs that transcend throughout their
bodies as part of their air respiration.  Their lungs are more
extensive and not like mammals.  Their bones are hollow with openings 
for the most part and air is very much part of the bird's internal
composition.  Air is not contained in birds like we see in mammals
and moves through birds much more easily.  Furthermore, the air sacs
are connected to the bone's internal air spaces.

It is highly suspected that birds are able to detect air pressure
changes and can sense weather changes and more importantly,
altitude.  Birds flying at night have the ability to maintain the
same altitude for huge distances during migration and do not need to
see the ground.  It is also believe that the ear is indeed the
sensing device for air pressure, but as I discussed above, air is
much more a part of the birds internal anatomy and air can move
easily throughout the bird so venting is probably not an issue.

I am unable to answer your question, but maybe I have touched upon the reason.

Steve Sample
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At the back of the throat birds have a cleft which is by the inner ear
opening. This cleft helps to regulate the pressure changes! Scientists
think that the inner ear may play a huge part in helping birds to
migrate and detecting storms.

Grace Fields
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