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Mysteries of Migration:
Slideshow and Lecture by Ron Levalley
by Kate Marianchild
Bird migration has mystified humans since we acquired a sense of
wonder. Birds disappeared in the fall and arrived in the spring, and no
one had any idea where they had been in the meantime. Ancient people
would have been astonished to know that the beautiful flyers that came
and went twice a year were more familiar with distant and exotic lands
than they were. As humans began traveling long distances across the
world by ship and by air we gained knowledge of the destinations of
migrant birds, and over the last several decades we have learned that
birds navigate by the sun, the stars, magnetic fields, and smells. But
no one has ever known exactly what happens during migration: do the
birds stop to eat or drink? if they eat, what do they eat? do they
sleep? do they fly a straight course or meander? how high do they fly?
The mystery has always been compounded by the fact that many birds
migrate exclusively at night.
Well, exciting new developments are on the wing. With the use of tiny
transmitters and satellites scientists can now sit in front of computer
screens and watch migrating birds all around the world as they eat,
sleep, and veer off course to feed on islands in the middle of the
ocean. Ron LeValley, an eminent biologist, ornithologist, and
photographer, will deliver a slideshow lecture on this fascinating
subject on Thursday, October 18, at the Ukiah Civic Center at 7 p.m.
LeValley�s talk will focus on seabirds that migrate extraordinarily
long distances and the challenges facing small-population migrants.
This Peregrine Audubon Society event is free to the public but
donations will be gratefully accepted.
It is a common and comfortable myth that migrating juvenile birds are
led to their wintering grounds by their parents. In fact it is only
among geese, cranes, and some other fresh-water waterfowl that such
parental shepherding occurs. One of the birds that LeValley will talk
about is the Bristle-thighed Curlew, a long-legged shorebird that nests
in a small area of western Alaska called Beringia. The adult females of
the species desert their chicks as soon as the chicks can fly, at four
weeks old, and fly to a food rich area in the Yukon where they fatten
up for their upcoming migration. The males soon take off as well,
leaving the chicks to frantically feed and practice flying on their
own. In late August and early September the adults begin their
migration, the endpoint of which is sometimes 5,000 miles away on
remote islands in the South Pacific. They make the flight non-stop, as
they lack waterproof plumage and therefore cannot rest on the water.
The juveniles leave a few weeks later and fly the same distance without
adults to guide them, relying on genetically programmed cues. No one
knows exactly how either the adults or juveniles find their tiny island
destinations in the vast Pacific, but most arrive safely.
Another bird we will learn about is the Laysan Albatross, a seabird
that nests on the northwest Hawaiian islands and flies several thousand
miles to the coasts of California and Alaska to collect oil-rich squid
and other fish for its chicks. LeValley will also bring us up to date
on avian migration records. The Arctic Tern, which migrates 22,000
miles round trip from the Arctic Circle to Antarctica, may now be
challenged for its title as the longest-distance migrant in the world.
Ron LeValley is founder and senior biologist of Mad River Biologists in
McKinleyville. He is the California coordinator for the Pacific Coast
Joint Venture, a public/private partnership funded by the North
American Wetlands Conservation Act to promote conservation. LeValley
lectures all over the western United States at Audubon meetings, bird
festivals, and ornithological conferences, where he is frequently the
keynote speaker. He is also a founding member of the Mendocino Coast
Photographer Guild and Galley in Fort Bragg, where he displays his
nature and wildlife photographs. His passion for the natural world is
rivaled only by his desire to share that passion.
The Ukiah Civic Center is at 300 Seminary Avenue. From 101 take Perkins
west to State Street (3rd light). Go left on State Street and turn
right on Seminary. Take Seminary to the end. To join Peregrine Audubon
Society and receive a newsletter with articles and announcements about
programs and field trips, please send $15 to PAS, P.O. Box 311, Ukiah,
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