Parasite-mediated competition among red-legged partridges and other lowland gamebirds.

Abstract

Evidence suggests that the transmission of shared parasites from ring-necked pheasants (Phasianus colchicus), specifically the caecal nematode Heterakis gallinarum, may be 1 cause of the decline of the gray partridge (Perdix perdix) in the United Kingdom (UK) over the past 50 years. It may be a factor preventing the recovery of the remaining wild gray partridge populations. Trials were undertaken to investigate whether the red-legged partridge (Alectoris rufa) also is involved in this interaction, by exposing individuals of all 3 host species to infection on 7 gamebird estates. The low rate of parasite establishment in the red-legged partridge demonstrated that, as with the gray partridge, the parasite cannot persist in this host species. The lack of a relationship between H. Gallinarum intensity and red-legged partridge condition indicated that, as with the ring-necked pheasant, this parasite does not seriously affect its host species. Hence, red-legged partridges play little or no role in the interaction mediated via H. gallinarum that occurs among UK lowland gamebirds, since they are unlikely to be either another source of deleterious infection to the gray partridge or adversely affected by the transmission of H. gallinarum from ring-necked pheasants. Ring-necked pheasants are thus implicated as being solely responsible for maintaining infections of H. gallinarum in other lowland game birds in the UK and any associated effects.