New Ohio Sea Grant research indicates nocturnal migrating songbirds that will be in the spotlight this month, especially during the Biggest Week in American Birding on May 5-14, might rely on archipelagos like North, Middle and South Bass islands on Lake Erie as a navigation aid or resting place.
Just like the crowds for people who venture to the the islands to have a good time, listen to music and party at night, the popular islands also offer landing habitat for birds, which migrate over Lake Erie under the cover of darkness in large flocks.
It’s possible the warblers and all of the other birds might need a rest stop, say researchers, or a cool drink or a bite to eat if caught over the lake as dawn approaches.
“Lake Erie is a barrier for migrating birds. It’s not huge like the Gulf of Mexico, but there are 30 to 40 miles between Ohio and Canada, and a bird that gets in trouble over water is going to have a large problem,” said Verner Bingman, Distinguished Research Professor of Neuroscience in the Department of Psychology at Bowling Green State University.
Although Lake Erie is a topographical barrier, many songbirds will cross it during their nocturnal migrations. However, birds could potentially use the island archipelago in the central-western basin of Lake Erie to m mitigate some of the possible negative consequences of a lake crossing, such as a greater risk of wind-drift over emptier parts of the lake, as well as offering a safe landing area should dangerous weather arise.
In research funded by Ohio Sea Grant, Bingman and Murphy Harrington, a master’s degree student in biology, set up infrared cameras last fall on Middle Bass Island to detect the directions of movements of individual nocturnal migratory birds, such as warblers, vireos, thrushes and sparrows.
They compared the results to individual birds migrating over Bowling Green and groups of birds, detected by Doppler radar, migrating over Cleveland.
They found that the nocturnal migrating songbirds move in a south/southwest direction, but there is little night-to-night variation in their movements. The paths of individual birds over Bowling Green are more spread out and over Cleveland were oriented in a different direction.
“So this indicates that birds are actually using those islands to maintain direction, and once they’re over the land, like in Bowling Green, they don’t have a reliable ground reference to account for error,” Bingman said. “They seem to be following the islands as a leading line to maintain a preferred migratory bearing. An additional adaptive benefit to following the islands is that should inclement weather arise, they could get themselves out of trouble.”
Bingman plans to continue statistical comparisons and repeat the study this spring and fall as well as next spring in order to have two years of data. He also plans to make ground-based observations on the flight directions of the songbirds in the early morning to see if the birds arrive from all directions to use the land as an oasis for rest.
The research could contribute to better strategies to manage environmental topography for migration.
“The migrations are an important source of economic activity around Lake Erie. Thousands of people come in to watch the birds. We could develop policies to support this,” Bingman said.
This research also has relevance for wind turbine development in Lake Erie because of the importance of Ohio and Lake Erie for migratory birds, particularly small songbirds,” Bingman said. “Should there be development, this kind of data could inform policymakers and developers if they are going to put turbines in Lake Erie — where should they put them, where environmental impacts would be the least. From our research: You don’t want them anywhere near the islands.”
The Ohio Sea Grant College Program is part of The Ohio State University’s College of Food, Agricultural, and Environmental Sciences and NOAA Sea Grant, a network of 34 Sea Grant programs dedicated to the protection and sustainable use of marine and Great Lakes resources. For more information, visit ohioseagrant.osu.edu.