Influence of temperature on the wintering avifauna of a northern lberian coastal farmland

Abstract

The abundance of wintering passerines in a coastal farrnland was rneasured by rneans of line transects for eleven years. There were marked variations in the abundance of rnost species between December and January. There was no apparent association of rneasured local temperatures with the abundance of any of the species. These data suggest that birds wintering in these coastal farmlands rnust be primarily affected by other environmental factors external to the coastal farmland. Variation in the abundance of sorne species seerns to be a consequence of the effect that severe winters have on resident and non-resident populations. However, the hypothesis that some of these species could be affected by land-use changes is not excluded.