Gray gull

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Gray gull
Gray Gulls-6174.jpg

Gray gull ( Leucophaeus modestus )

Systematics
Class : Birds (aves)
Order : Plover-like (Charadriiformes)
Family : Laridae
Subfamily : Seagulls (larinae)
Genre : Leucophaeus
Type : Gray gull
Scientific name
Leucophaeus modestus
( Tschudi , 1843)
Resting gray gulls

The gray gull ( Leucophaeus modestus , Syn . : Larus modestus ) is a medium-sized bird species within the gulls . Their breeding area is in the Atacama Desert in western South America. Outside the breeding season, it can be found there along the Pacific coast.

Like several other sub-tropical species, it is predominantly dark to medium gray. Due to the similarity, a close relationship to the male gull from Baja California has been assumed so far . Recent genetic findings from 2005 do not confirm this. According to these, the male gull is placed in the genus Larus , the gray gull in the genus Leucophaeus .

description

The gray gull is one of the medium-sized gulls with a length of about 45 cm. It weighs between 360 and 400 g. Adult birds show predominantly lead-gray body plumage; the top is darker than the bottom. The head is light gray to whitish in the breeding plumage and dark gray in the winter plumage. The bill and feet are black, the iris is brown. The hand wing is black, the rest of the wing is dark gray on top with black arm wings. These and the inner wings of the hand have white tips that form a light-colored trailing edge. The tail wears a black subterminal band and also has a light rear edge.

distribution and habitat

The gray gull breeds in northern Chile and possibly southern Peru . Here it occurs in highland deserts with no vegetation, such as the Atacama Desert, which can be located between 35 and 100 km from the coast. It looks for its food on the sandy beaches of the Pacific; she avoids rocky areas. Outside the breeding season, the distribution area extends from the equator southwards to the southern center of Chile.

Way of life

The gray gull feeds mainly on the small crab species Emerita analoga , which it prey on wading in the littoral at low tide . Furthermore fish or nereids are caught by diving . The former are often used as baby food. Outside the breeding season, the species can be found in harbors and in the wake of fishing boats.

Gray gulls breed in very large colonies with up to 60,000 nests on 5.5 km². The density is about 1 nest per m². The breeding season is between November and January, and the eggs are laid from mid-December. The species does not breed in years when the El Niño weather phenomenon occurs more frequently . The nest consists of a shallow hollow, often near a boulder. The clutch consists of 1–3, but mostly two pale, almost whitish eggs, the surface of which is extremely low in evaporation. It is incubated for 28–31 days. While one partner stays with the clutch during the day, the other flies to the coast to look for food. There is only one feeding flight per day. The other partner flies to the coast after dark and returns at dawn. The young are huddled for several days after hatching and develop faster than most other species. After 40 days they leave the breeding site and go to the coast.

Existence and endangerment

The world population is estimated at over 100,000 breeding pairs and, according to the IUCN, is not endangered (“least concern”). Because although the population is in decline due to massive collection of eggs (sometimes up to 30,000 in a colony), it can be assumed that there will always be sufficient brood population in the more remote areas.

literature

  • Josep del Hoyo , Andrew Elliott, Jordi Sargatal (eds.): Handbook of the Birds of the World. Volume 3: Hoatzin to Auks. Lynx Edicions 1996, ISBN 978-84-87334-20-7 , p. 602.
  • JD Goodall, RA Philippi B. and AW Johnson: Nesting Habits of the Peruvian Gray Gull , The Auk , vol. 62 (1945), pp. 450–451 ( PDF , accessed June 27, 2011)
  • Gerald S. Tuck, Hermann Heinzel: The sea birds of the world , Paul Parey publishing house, Hamburg / Berlin 1980, ISBN 3-490-07818-7
  • J.-M. Pons, A. Hassanin, P.-A. Crochet: Phylogenetic relationships within the Laridae (Charadriiformes: Aves) inferred from mitochondrial markers . Molecular Phylogenetics and Evolution, Volume 37, Issue 3, December 2005, pages 686-699 doi : 10.1016 / j.ympev.2005.05.011

Individual evidence

  1. ↑ Pons et al. (2005), p. literature
  2. ↑ a b c Del Hoyo et al. (1996)
  3. ↑ BirdLife Species Factsheet, s. Web links

Web links

Commons : Gray Gull ( Leucophaeus modestus )  - Collection of images, videos and audio files