Mérgulo Atlántico

Taxonomía

Nombre científico

Alle alle

Autoridad

(Linnaeus, 1758)

Orden

Charadriiformes

Familia

Álcidos

Género

Alle

Distribución y hábitat

Área de cría

NA, PAL : coasts of high Arctic from ne Canada to nw of Russia; more rarely to Bering Strait

Área no reproductiva

s in Gulf Stream to North Carolina; to n British Isles and North Sea

Migración

Complete migrants

Comportamiento

Little auks breed in large colonies on marine cliffsides. They nest in crevices or beneath large rocks, and may build rudimentary nests by bringing small pebbles and/or old grasses and lichen into the cavity, where they lay a single egg.Their single pale greenish blue egg is placed in a crevice of the rocks. Dovekies, like other alcids, are monogamous and have high nest-site fidelity, meaning that they often reusing the same cavity as a nest site by the same pair, year to year. Eggs are generally incubated by both parents equally, for roughly a month (28-31 days), until chicks begin to pip at about 25 days. Hatchlings generally weigh a mere 21 g and are unable to thermoregulate on their own. The hatchlings are brooded for approximately 5 days until they are able to thermoregulate, after which they are only attended to for feeding by parents. Young dovekies fledge from their nests at an age of 26-29 days old, synchronously with conspecifics on the colony, usually at night. All dovekies migrate south by winter into northern areas of the North Atlantic. The species is also commonly found in the Norwegian Sea. Late autumn storms may carry them south of their normal wintering areas, or into the North Sea, and can cause wrecking of these birds, along with other seabirds, on-land. <p>The glaucous gull and the Arctic fox are the main predators of little auks at colonies, with other gulls and raptors predating the species as well. In some cases, the polar bear has also been reported to feed on little auk eggs.

Conservación

Although populations appear to be decreasing, this is not currently thought to be rapid enough to be of concern for the species in the medium term, especially as global little auk numbers are generally rather fluid. Little auks have been shown to be able to buffer fluctuations in prey availability, caused by climate change, via plasticity in their foraging behavior, which is likely to make accurate conservation assessments more difficult.

Tendencia poblacional

declining