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Hummer tracking
 Q:
We want to know how the heck hummingbirds can be tracked through their
migrations. Do they show up on radar as itsy-teensy blips? Are they collared and
collected? Does someone fly alongside and count and watch? —EWT,
Jr., Clovis, California
[Bob and Martha Sargent /NCMNS, North Carolina Museum of
Natural Sciences] A leg band on a hummer
A: Your ideas are not so far fetched. We count them (although no one
flies alongside) and band them (their legs, not their necks). We don’t use radar
to track blips but great groups of migrating hummingbirds do show up on weather
radar as large clouds, says Greg Butcher, Director of Citizen Science, Audubon
Science Office. For years, meteorologists wondered what caused the radar images.
We depend on birdwatchers to track hummingbird migration in the spring and
fall as the birds wing in, (or out) from non-stop flights across the Gulf of
Mexico. See Further Surfing.
The tiny aluminum bands come in different sizes for different hummers and
measure typically about 1.8 millimeters across— two poppy seeds across. An
authorized bird bander captures a hummingbird with a trap or net. She may slip
the bird into the toe of a nylon stocking while she examines it and records
where and when she banded the bird, its age, sex, and other descriptive
information.
The bander puts the partially opened band into special pliers and slides the
band over the bird’s leg. After crimping the band into a good fit, she releases
the hummingbird. Sometimes the blasé
bird merely returns to the feeder that lured him into captivity. Mostly he flies
off. We recapture only about 1 in 1,000 banded hummers at sites even 10 miles
(16 km) distant from where they were banded. So, determining migration patterns
is slow work.
The bander sends the data to the 100-year old North American Bird Banding
Program. Citizen scientists observe, count, and report findings to the Banding
Program, universities, and such groups as the Audubon Society.
By the way, the first recorded instance of bird-banding recovery happened in
1595 France. One of Henry the IV’s peregrine falcons tore after a bustard and
didn’t return. The banded falcon showed up 24 hours later in Malta—1,350 miles
(2,170 km) away.
Further Surfing:
North
Carolina Museum of Natural Sciences
Sid
Gauthreaux, Clemson University: Radar ornithology
George S. Young,
University of Pennsylvania: detecting bird echoes in weather radar images
Journey North: How to track hummingbird migrations
Audubon and Cornell University, eBird: record
birds you see
Louisiana Ornithological
Society: How to identify individual hummers
Lanny Chambers, hummingbirds.net:
attracting, watching, feeding, studying hummers
(Answered May 30, 2003)
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