Deutschlander Discusses Migration – Hobart and William Smith Colleges \
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Deutschlander Discusses Migration

Associate Professor of Biology Mark Deutschlander is featured in a Democrat and Chronicle article about solar geolocators, devices being used to track bird migration habits.

“I think it’s pretty significant in terms of our understanding of migration. Every time a new technology is introduced, our understanding of this amazing phenomenon increases dramatically,” said Deutschlander.

The article states the devices have already provided some data that surprises the researchers. Of Deutschlander, it says, “He was also intrigued that one of the recaptured wood thrushes had chosen to follow a land route around the Gulf of Mexico in spring, while the others had flown over it. Deutschlander wonders if that choice was related to the fat levels of the bird, or its energetic condition. Migratory birds can increase their body mass by 50 percent for migration, he noted.” The article also explains one of his areas of research pertains to “how fuel stores influence birds within the same population to make different choices during migration.”

Deutschlander, a member of the faculty since 2002, holds a B.S. from SUNY-Geneseo and his Ph.D. from Indiana University. He is researching animal migration and sensory biology, how animals use a variety of cues for finding their way and how birds sense and use visual cues in the sky for migration. He is president of the board of the Braddock Bay Bird Observatory, which bands thousands of songbirds each spring and fall. He has traveled to Australia, British Columbia, Mexico and Trinidad and Tobago as part of his work.

The complete article follows.


Democrat and Chronicle
Tiny bird ‘backpacks’ help to track migration habits
Bob Marcotte • Staff writer • February 26, 2009

 

Tiny high-tech “backpacks” placed on songbirds represent a new leap forward in bird tracking and promise to provide important insights into bird migration – where individual birds go and, just as importantly, where they stop along the way, two local researchers say.

And that, in turn, could help identify critical wintering and stopover habitats that must be preserved in order to help threatened species survive.

“I think it’s pretty significant in terms of our understanding of migration. Every time a new technology is introduced, our understanding of this amazing phenomenon increases dramatically,” said Mark Deutschlander, associate professor of biology at Hobart and William Smith Colleges. He is also president of the board of the Braddock Bay Bird Observatory, which bands thousands of songbirds each spring and fall, primarily on the Manitou peninsula near Braddock Bay in Greece.

“It’s very neat that the devices weigh only about a gram or so,” added Christopher Norment, professor of environmental science and biology at State University College at Brockport who studies grassland birds in western New York.

“This technology is a very important advance and will aid in conservation efforts.”

The new devices, called solar geolocators, were placed on 14 wood thrushes and 20 purple martins, according to a recent report in the journal Science. For the first time, researchers were able to track the exact routes followed by individual birds to their tropical wintering grounds and back.

The devices sense and record sunrise and sunset each day. When researchers removed the sensors and downloaded the information, they were able to calculate where the birds had been each day to within three to six miles.

Most banding of songbirds has relied on placing tiny, identifying aluminum bands on the birds’ legs at banding stations, releasing the birds, and then hoping that they will be recaptured elsewhere or, if found dead, that the bands will be turned in. This happens with only a tiny percentage of banded birds, and even then banders have no idea where the birds were between the initial banding and recapture.

More sophisticated satellite tracking devices have been too large for use on small songbirds, and even smaller radio-tracking devices required someone to literally follow the birds by car or plane, close enough to pick up the signal.

“It’s been very difficult to track individual songbirds between their summer and winter grounds, and these devices will help us get a much better sense of where the birds actually go, and how long they linger at certain sites,” Norment said.

The solar geolocator devices were placed on the thrushes and martins in 2007 at breeding locations in northern Pennsylvania. The following summer, devices were retrieved from seven of the birds. Despite the relatively small number of retrievals, the data they yielded provided some startling insights.

For example, researchers and even amateur birders have long known that the spring migration occurs more quickly than the return flight in fall. However, Deutschlander said he was “really shocked” to learn that the birds in this study were traveling up to 360 miles a day in the race to reach and claim the best breeding locations.

He was also intrigued that one of the recaptured wood thrushes had chosen to follow a land route around the Gulf of Mexico in spring, while the others had flown over it. Deutschlander wonders if that choice was related to the fat levels of the bird, or its energetic condition. Migratory birds can increase their body mass by 50 percent for migration, he noted.

That’s one of Deutschlander’s areas of research – trying to understand how fuel stores influence birds within the same population to make different choices during migration.

Nonetheless, only seven geolocators could be retrieved from birds returning to known breeding locations. So it is unlikely these new devices will be replacing traditional banding methods anytime soon.

For one thing, many of the birds caught at banding stations are in the midst of migration, headed for points unknown. So the chances of recapturing them and retrieving devices from them would be even smaller than in the Pennsylvania study. Moreover, it would probably be “prohibitively expensive” to place them on the number of birds banded each year, Norment said.

Braddock Bay Bird Observatory alone banded 3,823 songbirds last spring, and another 5,135 in the fall.

Even so, Deutschlander said he would like an opportunity to place the devices on birds that return each year to nest in the immediate neighborhood of the banding station. Some of these birds, such yellow warblers, common yellowthroats, and song sparrows, have been recaptured several years in a row.

There would be a much higher probability of retrieving geolocators placed on those birds, Deutschlander noted.

BMARCOTT@DemocratandChronicle.com