As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday, 30 October 2015

Study finds migration strategy predicts stopover ecology in shorebirds


For migratory birds, how long you stop and how much you eat depends on how long your next flight is

Date:October 22, 2015

Source:De Gruyter Open

As anyone who has ever taken a long car trip knows, frequent rest and refueling stops are needed to make it to the destination. For migratory birds, this is the case as well, only they fuel up on food during their rest stops and put on large amounts of fat in the process. However, not all bird species have the same migration strategy, that is, in terms of their stopping times and eating rates. Some birds stop and feed for weeks at a time, and some do so for brief periods of one or two days. Now, a new study from online journal Animal Migration, has uncovered one of the reasons for this difference, and it has to do with the length of the next flight.

In the article, published now fully in open access by De Gruyter Open, Jessica Henkel and Caz Taylor, from Tulane University in New Orleans, LA, studied three species of migratory shorebirds (semipalmated sandpipers, western sandpipers, and dunlins), which all naturally differ in migration strategy during their spring migration in North America. One makes a series of short flights with multiple stops in between, one has the opposite behavior, with one or two very long flights northward, and only stops once or twice, and the third species is somewhere in the middle.

By capturing birds from all three species at sites along the northern Gulf of Mexico, and measuring their stopover times and refueling rates, the authors found that the long-distance migrants tended to stay longer at the refueling sites, and they gained weight faster than the short-distance birds. The birds that only make short flights tended to have shorter visits at the same sites, and did not gain as much weight.

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