Relations of nesting behavior, nest predators, and nesting success of wood thrushes (Hylocichla mustelina) to habitat characteristics at multiple scales
Date of Graduation
Davis College of Agriculture, Natural Resources and Design
Wood Science and Technology
Petra Bohall Wood.
During 1998--2000, I examined the relationship between the reproductive success of a declining Neotropical migrant songbird, the wood thrush ( Hylocichla mustelina), and surrounding habitat within the highly forested region encompassing the northwestern portion of the Monongahela National Forest, West Virginia, USA. I measured nest fate, food delivery rates, and nest attendance rates of 56 videotaped nests and then related these variables to habitat measured at three concentric scales: nest site (11.3 m radius), territory (100 m), and landscape (1000 m). Predation was the most common source of failure (23 of 26 failed nests), and southern flying squirrels ( Glaucomys volans) were the most common predator (n = 8). Probability of fledging was positively related to territory level amount of 30--49 yr old forest, and at the landscape level was negatively related to open, non-forested area and positively related to mean patch fractal dimension (a measure of shape complexity) of mature (>50 yr old) forest. I found no evidence of nestling food limitation, but, as with probability of fledging, food deliveries and nest attendance rates were positively related to measures of shape complexity of mature forest within the landscape. I also used videotapes of nests to examine the efficacy of traditional methods of predicting nest predators and nest fates. Specifically, I predicted the nest predator group (avian, mammalian, snake; all 56 nests) and nest fate (fledge/fail; n = 27 nests) of nests and compared my predictions with videotaped results. Nest predator group was incorrectly assigned for 12 of 21 depredated nests for which predator identity was known. Fates of 23 of 27 nests were correctly classified. Thus, traditional methods appear to be effective at assigning nest fate, but ineffective at classifying nest predator. In another study, I compared four years (1996--1999) of off-road point counts of forest dwelling songbirds with counts from the North American Breeding Bird Survey (BBS) routes in the region. I generally found low agreement between BBS counts and point counts. I discuss possible reasons for this lack of agreement.
Williams, Gary E. Jr., "Relations of nesting behavior, nest predators, and nesting success of wood thrushes (Hylocichla mustelina) to habitat characteristics at multiple scales" (2002). Graduate Theses, Dissertations, and Problem Reports. 1651.