Winter and Spring Survival of Radio-Tagged Gray Partridge in North Dakota

I studied survival of 100 radio-tagged gray partridge (Perdix perdix) in North Dakota from winter to the beginning of nesting during 1985-87. Radio transmitters appeared to cause significant mortality among captured partridge (34%) during the first week postrelease, after accounting for mortality expected from other sources. Survival of partridge living >7 days posttrapping (n=55) from early January to 1 May was 38%. The major source of mortality after the first week was raptor predation. A Cox's proportional hazards analysis revealed that body mass (P=0.003) and sex (P=0.04) were significantly related to probability of survival. Partridge weighing ≥400 g had higher survival (50%) than those weighing <400 g (20%). Females had greater survival (59%) than males (19%)