Flight Speeds and Wingbeat Frequencies of the Magnificent Frigatebird

Schnell, Gary

Wingbeat frequencies and flight speeds of Magnificent Frigatebirds were recorded with a Doppler radar in the Dry Tortugas, Florida. The flapping rate averaged 2.84 beats per second (SD 0.14) and was not significantly correlated with flight speed, providing further evidence that the birds wingbeat frequency is essentially constant within species. The flapping rate is somewhat higher than predicted form the theory of mechanical oscillators when the distance from the end of the wing to the first articulated joint is used as an estimate for the average effective wing length. Flight speeds of birds in a flat calm averaged 22.55 mph. The highest average ground speed of 30.17 mph was obtained from frigatebirds flying in a 6 to 8 mph wind, and the lowest of 16.00 mph for birds flying into the 65 mph wind. Airspeeds were greater for frigatebirds flying into the wind than for those moving across or with the wind.

Flight Speeds and Wingbeat Frequencies of the Magnificent Frigatebird

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