The banded stilt, a graceful, nomadic water bird found in inland salt lakes in Australia, can somehow sense and move toward rainfall hundreds of miles away.

Australians often spot the birds within days of rainfall, said Reece Pedler, a biologist at Deakin University in Australia. And then, abruptly, the birds will disappear.

The mystery, he said, is “How do these birds know when to leave one place for another, and how do they do it so fast?”

To better understand the movements of the nomadic birds, Mr. Pedler and his colleagues tagged 21 banded stilts with satellite transmitters. Their findings appear in the journal Biology Letters.