Migrationsrouten des Alpenseglers

karte
Migrationsrouten des Alpenseglers

Der Alpensegler ist mehr als die Hälfte des Jahres ununterbrochen in der Luft. Die fliegenden Langzeitwanderer ernähren sich von „Luftplankton“, fliegenden Insekten, Arthropoden. Schlaf wie der Mensch kennt der Alpensegler nicht.
Nur zum Brüten lassen sie sich herab zu ihren Brutplätzen in den Alpen. Der Alpensegler erreicht ein Alter von zirka 22 Jahren

First evidence of a 200-day non-stop flight in a bird
Felix Liechti, Willem Witvielt, Roger Weber & Erich Bächler

The map shows South-Western Europe and Western Africa. Each colour represents an individual (blue=I1, green=I2, red=I3). The black point indicates the breeding site, coloured areas in Africa mark the centre (75%-kernel) of the individual wintering ranges and the grey area represents the 50%-kernel of all three birds together. 50% kernel densities are given for stopover sites along the migration route. Arrows indicate spring migration routes and only the last step of the autumn migration of one individual, because movements occurred mainly during equinox, when no latitudinal information could be derived. Map and kernel projection refers to WGS_1984 UTM_Zone 31N.
Being airborne is considered to be energetically more costly as compared with being on the ground or in water. Birds migrating or foraging while airborne are thought to spend some time resting on the ground or water to recover from these energetically demanding activities. However, for several decades ornithologists have claimed that some swifts may stay airborne for almost their whole lifetime. Here we present the first unequivocal evidence that an individual bird of the Alpine swift (Tachymarptis melba) can stay airborne for migration, foraging and roosting over a period of more than 6 months. To date, such long-lasting locomotive activities had been reported only for animals living in the sea. Even for an aerodynamically optimized bird, like the Alpine swift, flying requires a considerable amount of energy for continuous locomotive control. Our data imply that all vital physiological processes, including sleep, can be perpetuated during flight.

nightsky
Night over the eastern Atlantic

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