Subject: BIRDXXXX highlights (fwd)
Date: Apr 28 14:51:45 1994
From: Sid Johnson - Sid.Johnson at CCMAIL.JPL.NASA.GOV


>From Sid Johnson, Los Angeles CA.

I copied the following from rec.birds a year or two ago. It covers
more than just the Blackpoll. Forgive me Kathleen.

-Sid
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From: jespah at milton.u.washington.edu (Kathleen Hunt)
Newsgroups: rec.birds
Subject: OUTDOOR: migratory feats
Summary: birds can fly really, really far
Organization: University of Washington, Seattle

I've been reading through Gill's _Ornithology_ recently and just
reached the chapter on migration. He has a little section called
"Migratory Feats" that really sparked my interest, and I thought some of
you outdoor rec.birds people might find it interesting too.

This is reprinted without permission. This is a very nice
introductory ornithology text, by the way -- comprehensive and
well-written with a huge bibliography. ("A little light on the physiology,
though," says my advisor, who is of course a physiologist :-)

***********************************************************************
Migratory Feats

Long-distance migratory flights are extraordinary feats of physiological
endurance. The migrations of arctic shorebirds regularly exceed 13,000
kilometers one way from the high Arctic to distant South America. Red Knots,
for example, fly from Baffin Island to Tierra del Fuego. A banded Lesser
Yellowlegs flew 3220 kilometers from Massachusetts to Martinique, West
Indies, in 5 or 6 days. These and other migrants cross thousands of
kilometers of open ocean of inhospitable terrain without stopping,
stretching their fuel reserves and physical abilities to the limit.
Dangerous as nonstop crossings may be, they are often the only way to
reach a destination or they may be preferable to longer, safer routes
because of shorter flight time.

Every fall, vast numbers of migrants leave the coast of New England
and the maritime provinces of Canada, heading southeast over the ocean.
The capacity and predilection of larger, faster shorebirds such as the
Lesser Golden-Plover for such flights has been known for many years, but
radar studies now reveal parallel efforts by millions of small landbirds.
Up to 12 million birds have passed over Cape Cod in one night, embarking on
a tremendous nonstop journey of 80 to 90 hours. Wave after wave of the
migrants, such as the Blackpoll Warbler, depart at intervals of several
days, heading past Bermuda and from there continuing on to the Lesser
Antilles. Radar stations on Bermuda and Antigua pick up the approaching
and passing waves of migrants. As these migrants reach the latitudes of
Florida, they encounter strong trade winds from the northeast. The migrants
then fly with the wind to the southwest toward the north coast of South
America. The strong tail winds enable the tired travelers to make the
last half of the journey somewhat more easily.

Evidence of the strenuous nature of the trip and of the way that
migrants stretch their physical capabilities to the limit can be seen in
the exhausted condition of the birds that stop at Curacao, short of their
destination, when flight conditions have been poor. Little more than
feathered skeletons, they have depleted their fat reserves, metabolized
much of their protein, and drained the remnants of their precious body
water. Tim and Janet Williams (1978) point out that "the trip requires a
degree of exertion not matched by any other vertebrate; in man the metabolic
equivalent would be to run a 4 minute mile for 80 hours. If a Blackpoll
Warbler were burning gasoline instead of reserves of body fat, it could
boast of getting 720,000 miles to the gallon."

Eurasian migrants also face herculean challenges. Northern
Wheatears from Greenland start their journey to the British Isles by
crossing 2000 to 3000 kilometers of open ocean with no assurance of
favorable winds. Many European migrants fly 1100 kilometers directly
across the Mediterranean and then, almost immediately thereafter, 1600
formidable kilometers nonstop across the Sahara desert. In the spring,
they return across the Sahara, proceed 400 kilometers across the eastern
Mediterranean, fly 600 kilometers over bleak, foodless Anatolia (in Turkey),
and finally travel another 650 to 1100 kilometers across the open water
of the Black Sea. Still another route between Asia and Africa, used by
birds that breed in northern Russia, includes traversing 1600 kilometers of
Caspian desert plus 1700 kilometers of Saudi Arabian deserts and the
intervening water passages. Some migrants such as falcons and bee-eaters
cross from India directly to East Africa over 4000 kilometers of the Indian
Ocean.

From:
Gill, Frank B. 1990. _Ornithology_. W.H. Freeman & Co.: New York.

Gives you something to think about while watching fall migrants, doesn't it?

--
Kathleen Hunt ********* jespah at milton.u.washington.edu *********** U.W.
Zoology