Desert birds fly more than 2000 kilometers to find ephemeral lakes

Ben Parkhurst

Desert birds fly more than 2000 kilometers to find ephemeral lakes

A species of Australian shorebird can detect and then quickly fly to short-lived lakes that form in the middle of the desert after a significant rainfall, new research suggests. The bird, known as the banded stilt (Cladorhynchus leucocephalus), is slightly bigger than the largest sandpipers and typically lives along Australia’s southern coast. But it occasionally flocks inland to breed and raise chicks around the waters that accumulate on salt flats after rains that sometimes occur only once every 2 or 3 years. In a first-of-its-kind study, scientists strapped tracking devices to 21 birds and monitored their movements, in some cases for up to 13 months. The gadgets—about half the size of a matchbox (shown on bird in image above) and powered by solar cells the size of a postage stamp—were programmed to record data for 10 hours and then save energy by shutting down during the 16 hours that followed. The results were surprising: In some instances, birds left two widely separated locations and crossed deserts along very different routes to converge on the same remote inland lake, the researchers report online today in Biology Letters. One of these migrations covered more than 2200 kilometers in 2.5 days, a movement nearly twice as long and twice as rapid as those previously known for other desert waterbirds, the researchers say. Just as surprising was the timing of some of these trips: Whereas some migrations commenced just after the distant rainfalls occurred, several others didn’t begin until weeks after the lake-generating rains had come and gone. Therefore, it isn’t clear what cues the straggling birds used to discern and then home in on the lakes: It’s not likely to have been the long-gone weather patterns associated with the storms that dumped the rainfall, but it could have been smells emanating from the flooded salt lakes or their newly revived bounty of brine shrimp, the team suggests.

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