Proceedings of the Royal Society London B 272: 53-61 (2005)
The three dimensional flight of red-footed boobies: adaptations to foraging in a tropical environment.
Henri Weimerskirch, Matthieu Le Corre, Yan Ropert-Coudert, Akiko Kato, Francis Marsac
In seabirds a broad variety of morphologies, flight styles and feeding methods exist as an
adaptation to optimal foraging in contrasted marine environments for a wide variety of prey
types. Because of the low productivity of tropical waters it is expected that specific flight and
foraging techniques have been selected there, but very few information are available. By
using 5 different types of high precision miniaturised loggers (GPS, accelerometers-time
depth recorders, activity recorders, altimeters) we studied the way a seabird is foraging over
tropical waters. Red-footed boobies are foraging for day trip, never foraging at night,
probably as a result of predation risks. They make an extensive use of wind conditions, flying
preferentially with cross winds at median speed of 40 km/h, reaching highest speeds with tail
winds. They spent 66 % of the foraging trip in flight, using a flap-glide flight, with a
frequency of 3.7 flap per second, gliding 68% of the flight. But travelling at low costs was
regularly interrupted by extremely active foraging periods where birds are very frequently
touching water for landing, plunge diving or surface diving (30 landings h-1). Dives were
shallow (maximum 2.4 m) but frequent (4.5 dives h-1), most being plunge dives. While
chasing for very mobile prey like flying fishes, boobies have adopted a very active and
specific hunting behaviour, but the use of wind allow them to reduce travelling cost by
extensive use of glide. During the foraging and travelling phases birds climb regularly at
altitudes of 20-50 m to spot prey or congeners; during the final phase of the flight, they climb
at high altitudes, up to 500 m, probably to avoid attacks by frigatebirds along the coasts. This
study demonstrates the use by red-footed boobies of a series of very specific flight and
activity patterns that are not observed in temperate and polar seabirds, and have probably been
selected as adaptations to the conditions of tropical waters.
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