Migrating birds rush to spring breeding grounds

[Cara J]

When it comes to spring migrations, the early bird gets the best breeding site. Now, radar data have revealed that birds rush for that advantage, flying faster than they do in fall and fighting harder against unfavorable winds. “We know that birds get to the breeding grounds quickly. We’re starting to build the picture of how they do it,” said Kyle Horton, a radar ornithologist at the University of Oklahoma and first author of a study published this month in The Auk: Ornithological Advances. “They’re flying faster, and they’re also compensating for wind drift in a more efficient way, relative to fall migration.” In the past, researchers have studied migrations by observing when species show up at different locations. This approach has revealed that birds’ fall journeys take longer overall than their spring journeys, but it couldn’t show whether birds actually fly faster in spring. Banding studies have found that birds spend more time resting at stopover sites during the fall, which would extend their fall migrations even if they flew at the same speed in both seasons. Radar offers a solution. By measuring the time it takes for microwaves to bounce back from objects in the air, radar stations [...]

 

Read more: http://wildlife.org/migrating-birds-rush-to-spring-breeding-grounds/