P. Tryjanowski, Proximity of raven (Corvus corax) nest modifies breeding bird community inan intensively used farmland, ANN ZOO FEN, 38(2), 2001, pp. 131-138
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 av
oided by small birds as their nest sites. Birds were counted along 13 trans
ects (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 ne
sts. 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 arven
sis, the most abundant bird species. Neither the presence of raven nests no
r control pylons influenced the number of breeding bird species along 100-m
sections of the transect. Total density of breeding birds decreased with t
he increasing distance from raven nests, whereas it increased with the dist
ance 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 antipred
ator adaptation against nest-robbing by other predators.