The Red-footed Falcon Falco vespertinus population in the Danube Delta and its habitat selection for breeding

Abstract

The Danube Delta is an atypical and complex ecosystem on the border of the slowly shrinking breeding distribution of Falco vespertinus. In this paper, we study the population that breeds in this area and intend to understand its relationship with the environment in these circumstances. We registered 231 breeding pairs (bp), with a local density of 0.034 bp/km$^{2}$. We made a Nearest Neighbour Analysis which confirmed the natural condition of the facultative colonial nesting character of this species. In addition, in order to study its habitat preferences for nesting we did a binary logistic regression model and complemented its results with Manly's standardized habitat selection index for constant resources, calculated for each habitat class. The results obtained indicate that, for nesting in the study area, this species depends (positively or negatively) on the presence of Rook colonies, the weather, the habitat diversity and fragmentation, the abundance of open habitats like pastures, grassland, agricultural fields, beaches, and sand dunes.