Surprising moves of Magnificent Frigatebirds tagged in the Florida Keys

5/4/13: GPS satellite transmitters show unexpected nesting locations

Within days of placing GPS-equipped satellite transmitters on Magnificent Frigatebirds last October in the Florida Keys, we gained an unprecedented view of this intriguing bird’s trans-oceanic journeys.

With funding from the U.S. Fish and Wildlife Service and the help of Senior Refuge Biologist Tom Wilmers, we safely captured five adults on their island night roosts. The transmitters, which collect eight highly accurate fixes every day, have already charted long overwater flights to Mexico’s Yucatan Peninsula and the Caribbean coasts of southern Cuba and Central America, where three of the birds apparently nested.  Surprisingly, none of them settled in the Dry Tortugas, where a small breeding colony of Magnificent Frigatebirds – the only such site in the U.S. – nests each spring (these birds do not start reproducing until five to eight years old).

If our present fund-raising attempts are successful, we will deploy additional tracking devices on nesting Magnificent Frigatebirds in the Tortugas this spring. Our goals are to learn how far and for how long parents must forage to rear their young, how faithful they are to annual nesting sites, and the year-round effects of human disturbance, which is the most likely cause of the ongoing range-wide decline of this spectacular species.