Endoparasite Isospora sp. (Coccidia, Eimeriidae) affects the growth of starling Sturnus vulgaris nestling

The influence of coccidia on starling nestlings was analyzed. Isospora sp. was found in 67% of starling broods. Although some broods were heavily infe cted with Isospora sp., nestlings from most infected nests were on average heavier and had longer wings than nestlings from low infection and non-infe cted nests. Apparently, nestlings that were better fed, had also greater ch ance of being infected with Isospora sp. These results suggest that coccidi a affect the growth of starling nestlings - and, although not pathogenic, m ay affect the reproductive success of starlings, especially when the parent al feeding effort could not be sustained.