Friday, April 27, 2007

ABA: Wednesday p.m.

For the afternoon workshop during the American Birding Association's convention in Lafayette, La., I listened to Andrew Farnsworth discuss "The Sights and Sounds of Migration: Interpreting radar and listening to flight-calls." Farnsworth is a post-doctoral candidate at Cornell Lab of Ornithology... and a former team member of WildBird's award-winning Great Texas Birding Classic team. Always a pleasure to see birders once affiliated with WB go on to big things!

Radar can tell birders where, when and how many nocturnal migrants are flying, and flight calls can tell which migrants are overhead, Farnsworth said. Radar, in conjunction with weather forecasts, gives birders an idea of potential migratory fallouts -- when birds stop flying to rest and forage -- before or after a cold front moves through a region.

Farnsworth provided a crash course in reading weather maps, understanding how radar works, reading radar scans and discerning the information in a vertical wind profile and a SkewT, among other data. He offered loads of information before the refreshment break, and he was obviously pleased with the local radar images and the potential for lots of birds on the Louisiana coast. He and Brian Sullivan (right) talked of driving southwest to Peveto Woods Sanctuary to check out the birding.

Then Farnsworth talked about flight calls: the unique or not-so-unique calls that birds make while migrating at night. He's studied flight calls for years and played his Rosetta Stone -- the flight calls of 48 regular North American migrating warblers -- at high speed, eliciting laughter from the workshop participants. At slow speed, we could begin to detect the subtleties.

Flight calls offer the best option to study nocturnal migrants, Farnsworth said. With that information, researchers can identify stop-over locations and migration paths, he said, leading to conservation of those areas and regions.

Have you heard of BirdCast? Farnsworth mentioned the now-defunct project that used weather conditions and radar to create bird-migration predictions. Microphones recorded flight calls at night, while observers visited sites in the morning to analyze the predictions. He said the participants found a good correlation between the forecasts and the subsequent activity.

Want to learn more? Farnsworth recommended these sites:
Clemson University Radar Ornithology Lab (CUROL)
University of Wyoming department of atmospheric science
National Center for Atmospheric Research RAP Real-Time Weather Data

Flight calls
Old Bird
Raven: interactive sound analysis software

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