Survival and habitat use by ring-necked pheasants during two disparatewinters in South Dakota

摘要

Severe winter weather in the Northern Great Plains of North America can alter availability of winter cover and cause increased mortality of ring-necked pheasants (Phasianus colchicus). We monitored pheasant survival and habitat use via radiotelemetry during the second most severe winter in eastern South Dakota since 1892. We captured and. radiomarked 45 female ring-necked pheasants at the onset of the 1996-97 winter and monitored survivors through spring at 3 sites in eastern South Dakota. We also monitored 58 female ring-necked pheasants at the same sites during the 1995-96 winter, a winter characterized by below average temperature and average snowfall (winter severity rank: 35th). Survival of radiomarked hens in 1995-96 (0.61 [SE = 0.07]) was higher (P < 0.001) than that in 1996-97 (0.03 [SE = 0.02]). Mortality due to predation was higher (P less than or equal to 0.042) than mortality due to weather in both winters. Mortality due to weather did not differ (P = 0.787) between winters. However, 31 of 41 deaths occurred during blizzard periods in 1996-97, indicating severe weather increased the vulnerability of pheasants to predation. Radiomarked hens showed the highest preference for tall grass (>75 cm), cattail (Typha spp.) wetland, and corn food plot habitats in winter 1995-96, and early winter 1996-97. Shelterbelt and corn food plot ranked highest for pheasants that survived to the second half of the 1996-97 winter. We conclude that shelterbelt and food plot habitats are essential to the survival of pheasants in eastern South Dakota during extreme winter weather conditions.