Author : Nathan P. Pamplin
Publisher :
ISBN 13 :
Total Pages : 150 pages
Book Rating : 4.:/5 (561 download)
Book Synopsis Ecology of Columbian Black-tailed Deer Fawns in Western Oregon by : Nathan P. Pamplin
Download or read book Ecology of Columbian Black-tailed Deer Fawns in Western Oregon written by Nathan P. Pamplin and published by . This book was released on 2003 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Little is known about Columbian black-tailed deer (Odocoileus hemionus columbianus) because of their elusive nature and the logistical difficulty of studying them in densely forested and mountainous terrain. The Oregon Department of Fish and Wildlife has identified fawn survival as an important gap in the current knowledge of demography and their understanding of an apparent population decline. We used vaginal-implant transmitters to locate birth sites and capture newborn Columbian black-tailed deer fawns in the Umpqua National Forest in western Oregon. We used modified Clover traps to capture deer during the winter and early spring of 2000 and 2001. Vaginal-implant transmitters were inserted into 36 adult does in 2000 and 32 adult does in 2001. We identified a total of 42 birth sites within our study area using this technique and we captured 23 fawns which we monitored daily throughout the summer. We modeled birth site selection by examining both site-specific variables and characteristics that describe habitat structure across a nested, hierarchical range of four circular areas. We used logistic regression to compare 42 birth sites with 80 random sites. The model that explained the most variation included the amount of edge and the average slope within 1,000 m of the birth site. We radiocollared 23 fawns from 2000 and 2001; 19 were captured at the birth site, which was identified using the vaginal-implant transmitter, and 4 were captured opportunistically. Fawns were located at least every other day and we assessed habitat selection using selection ratios. Fawns used open and shelterwood patches more than their availability in the study area. Timber habitats were used most by fawns, but were used less than available. Survival was monitored daily from the fawns estimated date of birth to 76 days. The Kaplan-Meier survival estimate for 76 days was 44% (95% confidence interval=23-66%). We fitted our survival data to the Weibull distribution and took an information-theoretic approach to construct a priori models using fawn capture morphometrics and habitat variables within a 600 m and 1,000 m radius of the capture site. The model that best explained fawn survival time was the amount of roads within a 1,000 m radius of the capture site. A higher road density within fawn summer range increases fawn survival time by likely minimizing predator density due to vehicular disturbance.
