Chukar Seasonal Survival and Probable Causes of Mortality

Chukars (Alectoris chukar) have been introduced throughout the world. Despite this widespread distribution, limited information regarding seasonal survival, probable causes of mortality, and other basic life history characteristics is available to manage this harvested species. We estimated the probable cause of mortality for chukars with radiotransmitters by examining evidence at kill sites. We used model selection to evaluate influences of seasonal effects ( fall raptor migration, peak migration, and reproductive period), demographic effects ( age and sex), radio weight, and year on survival of chukars in western Utah, USA, by using a known-fate model in Program MARK and 2 years of telemetry data. We captured and randomly fitted 125 individual chukars with 2 different-sized radiotransmitters ( 97 F, 20 M, 8 sex undetermined). Model selection results showed our top 3 models accounted for 99% of Akaike's Information Criterion weight, and each one had seasonal and year effects. Two-week survival estimates were lower during peak raptor migration in both years and significantly ( P < 0.05) so in year 2 (2-week S = 0.87, 95% CI = 0.77-0.94) compared with other year 2 intervals (2-week S > 0.91). Annual survival was lower in 2005 (S = 0.03, 95% CI = 0.01-0.09) compared with 2006 (S = 0.19, 95% CI = 0.12-0.31). We documented 95 deaths and classified 56% unknown, 33% avian predation, 8% hunter harvest, and 3% mammalian predation. Our research suggests that predation on chukars is substantial during the peak fall raptor migratory period and that the hunting take under current regulations is relatively small and likely compensatory. ( JOURNAL OF WILDLIFE MANAGEMENT 73( 1): 89-97; 2009)