Feeding Niches of Woodland Birds in a Montane Coniferous Forest in Central Spain during Winter

Abstract

A short-term study of the feeding niche differentiation of some passerine birds was conducted in a montane pine forest in central Spain during one winter, and the results were compared with similar data from northern Europe. Only six species of passerines were fairly common in the study area. The distribution of densities seemed to be more even than in northern Europe. The so called pariform guild as defined in Scandinavian studies, was found to consist of three distinct groups of species according to their foraging patterns: a group of generalized ground, shrub and branch foragers, another of specialized foliage foragers and a third of specialized trunk foragers. The last group overlaps so little with the rest of the species, that it should be excluded from the guild. Parus montanus and Certhia familiaris are not found in central Spain, while they are common in northern Europe. Instead Sitta europaea and Certhia brachydactyla were relatively common. The higher average temperatures for the winter months in central Spain when compared with northern Europe may induce a greater resource abundance, which possibly explains the broader niche of Parus cristatus and the abundance of Sitta europaea. No major effects on the foraging patterns of Parus cristatus and Parus ater by the absence of Parus montanus were observed, but the distribution of P. cristatus in the pines may be affected by the presence of Sitta europaea.