>2) why do Gannets "elongate" their necks before take off from a colony?

Why do I get the feeling it's both to inform cliffmates AND gulp O2?
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"Gulping" O2 seems unlikely. Assuming "gulping" means swallowing, try it
yourself. It's a bad habit, makes you feel uncomfortable, leads to
belching and doesn't increase the oxygen in your blood. However, panting
or hyperventilating *will* increase blood O2 concentration. Gannets don't
appear to be hyperventilating when they stretch their necks. On the other
hand, birds naturally hyperventilate (or the next thing to it) when they
fly. The lungs don't end blindly, as ours do, but are connected to tubes
and air sacks that act as bellows during flight. Thus, more stale air is
expelled and "new" air is inhaled on each breath; the average concentration
of O2 within the lungs is higher and is renewed more often .

Herb Curl

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