Situación de los págalos (Stercorarius sp.) en el litoral catalán (NE de la Península Ibérica)

Abstract

Situation of Skuas (Stercorarius sp.) an the catalan coast (NE of the Ibenan Peninsula)
With scattered observations made from 1970 and regular sampling periods by boat during the winters of 1981-82 and 1982-83, 127 records of the genus Stercorarius on the Catalan Coast, were obtained. St. skua (59 records) is the most common Skua and behaves as a typical wintering species (from October until March-April) It is pelagic, with most observations between 5-13 nautical miles from the coast, it is aiso a scavenger and has a low frequency of parasitical activity. St. parasiticus (43 records) is a regular migrant aithough scarce in both passage periods (March-May and July-December) and rarer as a wintering species. It is more coastal than St. skua and concentrates in areas with abundance of Terns and small and medium-size Gulls. Its parasiticai habits are notorious and most individuais are adults (92%) in the light phase (67%). It seems that most unidentified recoxds of Skuas (20) belong to this species. St. pomarius (5 records) is a very scarce or even exceptional migrant.