Nesting ecology of Rio Grande wild turkeys in the Edwards Plateau of Texas

摘要

Rio Grande wild turkey (Meleagris gallopavo intermedia) numbers in the southeastern region of the Edwards Plateau (EP) have shown a significant decline since the 1970s; however, the remainder of the EP had stable populations during this period. Since 2001, research has been conducted in the southeastern EP evaluating factors which could be responsible for the decline of Rio Grande turkeys in this region of Texas.I used digital cameras to evaluate the effect of nest predation on the reproductive success of Rio Grande wild turkeys in the region. Nest predation was the leading cause of nest loss in my study and I documented frequent predation events involving ?1 predator species. While studying nest predation, I examined the effects of my methods, and those commonly used by others, on nest success. Nests with cameras failed at the same frequency as those without cameras but at a faster rate. Predation rates observed for artificial nests underestimated predation rates of real nests. Additionally, I photographed known turkey nest predators at 27% of random points with no eggs, suggesting that nest predation could be a random process depending on the nest predator?s unique search image. I also examined the spatial structure of the habitat surrounding nest locations of turkeys on my study sites to evaluate the effect of disturbance on nest-site selection. Out of 59 nests located on the Kerr Wildlife Management Area from 2005 through 2007, only 5 were in areas that had not been burned in the 9 years prior. Turkeys in my study consistently chose areas characteristic of the fire maintained, oak?juniper savanna historically found in the region.