La gaviota andina ( Chroicocephalus serranus ) es una especie de la subfamilia Larinae de la familia Laridae , compuesta por gaviotas, charranes y rayadoras. [3] Se encuentra en Argentina, Bolivia, Chile, Colombia, Ecuador y Perú. [4]
La gaviota andina estuvo durante mucho tiempo incluida en el género Larus . La investigación genética ha establecido que Larus sensu lato es parafilética [5] por lo que la Sociedad Estadounidense de Ornitología , el Comité Ornitológico Internacional y la taxonomía de Clements la trasladaron a ella y a otras 10 gaviotas al género Chroicocephalus . Sin embargo, el Manual de aves del mundo de BirdLife International los conserva todos en Larus . Los sistemas coinciden en que la gaviota andina es monotípica . [6] [3] [7] [2]
La gaviota andina mide de 42 a 48 cm (17 a 19 pulgadas) de largo y pesa alrededor de 480 g (17 oz); es uno de los miembros más grandes de su género. Los sexos son parecidos. Los adultos en plumaje nupcial tienen una capucha negra brillante con una media luna blanca detrás del ojo y un cuerpo mayoritariamente blanco con el dorso gris y, a veces, un rubor rosado en las partes inferiores. Su cola es blanca. La parte superior de su ala es mayoritariamente gris con un patrón alternado de blanco, negro, blanco y negro en las primarias . La parte inferior de su ala es de color gris pálido con una mitad exterior negruzca, excepto por grandes "espejos" blancos en las tres primarias más externas. Su pico, patas y pies son de color marrón negruzco con un tinte rojizo y su iris es marrón. Los adultos no reproductores tienen la cabeza blanca y las patas negruzcas. La gaviota andina tarda dos años en alcanzar el plumaje adulto. En su primer año tiene algunas manchas negras en la cabeza, un complejo patrón blanco y negro en las alas y una banda negra cerca del final de la cola. [8] [9]
The Andean gull is found year-round in the Andes from far southwestern Colombia south through central Ecuador and Peru, western Bolivia, and eastern Chile and western Argentina to about the latitude of the north of Chile's Aysén Region. Many individuals winter on the coast from central Peru south into northern Chile, but it is not known if these are from the highlands to the east of there or from the southern part of its range. The species has been recorded as a vagrant in Amazonian Peru and far southern Argentina.[8][9]
In its breeding season the Andean gull is found at lakes, bogs, marshes, and fields of the puna and páramo zones of the Altiplano. In elevation there it mostly ranges from 3,000 to 5,300 m (9,800 to 17,400 ft) but is found as low as 1,200 m (3,900 ft) in the southern part of its range. Wintering birds are typically found at river mouths and sand beaches along the coast.[8][9]
In the mountains the Andean gull feeds on earthworms, insects, amphibians, small fish, and occasionally eggs and chicks of waterbirds. In winter it also scavenges at ski resorts. Along the coast it feeds on offal, fish, and marine invertebrates. It walks, swims, and flys to seek food.[8][9]
The Andean gull breeds mostly during July and August. It sometimes breeds solitarily but more usually in small colonies. It nests along riverbanks and on islands in them and in lakes. The clutch size is usually two or three eggs but one or four are sometimes laid. The incubation period, time to fledging, and details of parental care are not known.[8][9]
The Andean gull's vocalizations include "agitated, sometimes tremulous “yeeer” calls" and "a hoarse “raggh-aggh-keeaagh” and other low raspy notes."[8]
The IUCN has assessed the Andean gull as being of Least Concern. It has a large range but its population size and trend are not known. No immediate threats have been identified.[1] "The species is probably vulnerable, with no large populations...breeding areas are in remote high-altitude lakes but many are increasingly subject to agricultural pressure and human disturbance."[8]
