Flight Speeds and Wingbeat Frequencies of the Magnificent Frigatebird

Abstract

Frigatebirds are well specialized for remaining airborne for long periods of time. Unfortunately relatively little is actually known about their flight capabilities. The Magnificent Frigatebird (Fregata •nagnificens) is primarily a New World species and is seen regularly along the southern coasts of the United States. In the Dry Tortugas, westernmost of the Florida Keys, they often roost in mangroves on Bush Key and on pilings on Garden Key, particularly during the warmer months; they can regularly be observed in flight in the vicinity of these roosts. Harrington et al. (1972) examined the effect of wind on frigatebird flight activities in the Tortugas and compared results with those obtained near another roost on Tarpon Key at the mouth of Tampa Bay, Florida. During the summer of 1967 I visited the Dry Tortugas and gathered information on wingbeat frequencies of Magnificent Frigatebirds and the effect of wind speed on their flight speeds