Proximity of raven (Corvus corax) nest modifies breeding bird community in an intensively used farmland

摘要

In this paper I tested the hypothesis that areas around nests of raven Con us corax built on electricity pylons in an intensively used farmland are avoided by small birds as their nest sites. Birds were counted along 13 transects (length 1000 m, width 200 m) starting from pylons with raven nests, as well as 13 control transect lines which started from pylons without any nests. These two types of transects did not differ with respect to the number of recorded bird species. However, the proximity of raven nests positively affected the total density of bird species, including skylark Alauda arvensis, the most abundant bird species. Neither the presence of raven nests nor control pylons influenced the number of breeding bird species along 100-m sections of the transect. Total density of breeding birds decreased with the increasing distance from raven nests, whereas it increased with the distance from control pylons. Contrary to expectations, these results indicate the positive impact of raven presence on breeding bird community in an open farmland. I suggest that breeding of birds near raven nests is an antipredator adaptation against nest-robbing by other predators. [References: 30]