Impact of a parasite Heterakis gallinarum on the body condition and breeding success of pheasants Phasianus colchicus.

Abstract

Pheasants in Britain are host for the intestinal nematode Heterakis gallinarum. Post-mortem examination of birds, largely of released stock, shot during the winter, found a negative correlation between Heterakis number and body condition. In February 1991, 50 females and 23 males were captured, all were survivors from a release in the previous summer. Half were dosed with an anthelmintic to remove gut parasites and the others given water to act as a control group. The subsequent survival and breeding success of each group were monitored. The anthelmintic-dosed males were more likely to establish territories and attract more females. There were no significant differences in survival or breeding success of the anthelmintic- or water-dosed females. Female survival was exceptionally low, possibly related to high levels of tick infestation in this area.