Invemada del Porrón bastardo Aythya marila en España

Abstract

From a compilation of 46 observations done in 22 locations, it can be drawn that wintering of Aythya marila in Spain is not an irregular phenomenon, as it has been considered up to now. The scarcity of individuals that come to Spain (the number increases when there is a cold ware in their wintering areas in the littoral of the NW of Europe), and the fact that they are not very obvious among other pochards, could be the reason why they are not observed more frecuently. It is mainly seen in the Norther and Eastern coasts of Spain, with only one irnportant interior location (Gallocanta lake). Although they usually come into view between December and March, some years they have been seen in October and November.