La colonización y expansión del estornino pinto (Sturnus vulgaris L.) y del estornino negro (Sturnus unicolor Temm.) en Cataluña (NE de la Península Ibérica)

Abstract

This article is about the colonization of the Sturnus vulgaris and the Sturnus unicolor in Catalonia. It describe the colonization process based on 3 inventories for each species, using the UTM projection grid 10 x 10 km as a primary unit. For 395 squares, the Stumus vulgaris occupied 13.1% of them in 1974, 33.6% in 1979, and 61.5% in 1982; the Sturnus unicolor occupied 3.5% in 1977, 18.7% in 1979 and 23.0% in 1982. The Sturnus vulgaris colonization rate from 1974 to 1982 has been studied. It has been found that the population increases its breeding localities following an arithmetic progression (y = – 9.77 + 9.93 x). It is shown that there is a significant correlation (P 0.001) between the zones in which cereals are heavily cultivated and the area which the Sturnus vulgaris occupied in 1982. A similar relationship has not been found with the Sturnus unicolor.