Intraspecific Nest Parasitism in the Starling (sturnus Vulgaris) in Northwestern Croatia

Dolenec, Z.: Intraspecific nest parasitism in the starling (Sturnus vulgaris) in northwestern Croatia. Nat. Croat., Vol. 10, No. 4., 315–320, 2001, Zagreb. This study reports intraspecific nest parasitism in starlings (Sturnus vulgaris) in the village of Mokrice, northwestern Croatia, in 1999 and 2000. Twenty one (30.5%) out of 70 observed nests during the two years contained one or two parasitic eggs. One parasitic egg was laid in 17 (24.8%) nests and two in 4 (5.7%) nests. No statistically significant differences were found between egg dimensions (length, breadth, volume, egg shape index) of parasitic females and hosts. Also, there was no statistically significant correlation between egg volume of parasitic and host eggs. There is thus no evidence that parasitic females select host nests on the basis of egg dimensions of the host. Parasitic females laid their eggs mostly in host nests that already had two or three eggs (in 72.8% cases).