Semester

Summer

Date of Graduation

2007

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

Petra Bohall Wood.

Abstract

During the post-fledging period, some juvenile songbirds appear to require early successional habitats at some level, suggesting that disturbance (whether natural or anthropogenic) in the landscape is important. Previous studies of juvenile Wood Thrushes (Hylocichla mustelina) have found them in early successional areas in which adults do not nest. My objective was to determine how juvenile Wood Thrushes used areas harvested through various silvicultural techniques within a forested landscape. I examined settled areas, habitat use, survival, and daily movements of 55 radio-tagged juvenile Wood Thrushes on a managed forest in the central Appalachian mountains of West Virginia during 2004 to 2005.;I tagged individuals as nestlings and as juveniles, and radio-tracked birds in the natal and post-natal period. I used Global Positioning Systems to record the location of each bird on a daily basis and sampled habitat variables at these locations. All locations were assigned to one of three landcovers (mature forest, sawtimber harvests, and early successional areas) on a digitized map of the study site. I examined the proportion of daily locations within each landcover. I measured the size of harvests and related size and age to use by juvenile Wood Thrushes.;Once independent from adults, most individuals preferred early successional areas, in particular large, older clearcuts, >13-ha in size and 7-11 years post harvest. Overall, radio-tagged Wood Thrushes tended to move from open areas to those with a denser understory as they transitioned from being dependent on adults to being independent. Survival was similar among cover types ( natal: P = 0.7, mature forest 91%, sawtimber harvest 80%, early successional area 88%; post-natal: 100% among all cover types).;Radio-tagged juvenile Wood Thrushes on my study remained in the natal areas approximately 3 weeks before moving to post-natal sites. Similar to other studies, some individuals were located in up to 4 separate post-natal sites prior to migration or transmitter battery failure. Sizes of and duration within settled areas were similar to those documented in previous studies but distances between settled sites were shorter (natal to initial post-natal: x = 760 m; initial to subsequent: x = 930 m), as were daily movements between consecutive locations, suggesting juvenile Wood Thrushes on my study site did not need to move long distances to find suitable habitat. Among first post-natal settled areas occupied at least 5 days in which ≥80% of locations were within one cover type, settled areas were smallest in early successional areas (0.8 ha), intermediate in mature forest (1.0 ha), and largest in sawtimber harvests (2.8 ha) ( P = 0.01); however, settled areas within sawtimber harvests averaged smallest among subsequent settled areas with this criteria.;I examined mist-net captures of songbirds between two silvicultural methods that create early-successional patches, clearcuts and deferment cuts. In late-July and late-August 2004 and 2005, I sampled three clearcuts and three deferment cuts similar in size (14.7--16.2 ha) and age (5--8 years) on my study site. No overall differences (P > 0.05) in abundance, species richness, or diversity were detected between the two treatments for adult or juvenile captures. Of the two species with the highest captures, significantly more juvenile Hooded Warblers (Wilsonia citrina) were captured (P < 0.05) in clearcuts than in deferment cuts, while juvenile Chestnut-sided Warblers (Dendroica pensylvanica ) were captured more often in deferment cuts (P < 0.05). Early successional patches are important in the post-fledging ecology of Wood Thrushes as well as other migratory songbirds. My results do not indicate clearcuts or deferment cuts are more favorable to all birds, rather each treatment was important to at least one guild or species. Thus, both harvest types appear suitable for use by land managers interested in creating early successional habitats for songbirds.

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