Title page for ETD etd-3739142349751421


Type of Document Dissertation
Author Rivera, Jorge H. Vega
Author's Email Address jorge@vtvm1.cc.vt.edu
URN etd-3739142349751421
Title Premigratory movements of a long-distance migratory species: the Wood Thrush (Hylocichla mustelina)
Degree PhD
Department Fisheries and Wildlife Sciences
Advisory Committee
Advisor Name Title
Haas, Carola A. Committee Co-Chair
Stauffer, Dean F. Committee Co-Chair
Bolstad, Paul V. Committee Member
Kirkpatrick, Roy L. Committee Member
Oderwald, Richard G. Committee Member
Keywords
  • molt
  • habitat use
  • dispersal
  • radiotelemetry
  • Wood Thrush
  • and conservation.
Date of Defense 1997-01-05
Availability unrestricted
Abstract
The postbreeding period in migratory bird species is an important, but often neglected,area of knowledge. From May-October of 1993-95, I studied the breeding andpostbreeding ecology of 61 adults and postfledging movement of 43 juveniles in aradio-tagged population of Wood Thrushes (Hylocichla mustelina) on the U. S. MarineCorps Base, Quantico, Virginia (38 30' N, 77 25' W). Fledglings became independent 0 0from their parents at 28-36 days post hatching and dispersed 307-5300 m from their natalsites to join flocks of conspecifics. About half (46%) of the young birds stayed in onedispersal site until migrating, but the rest visited other sites. In 40 instances, 15fledglings moved up to 6 km out of the dispersal site and, after 1-5 days, returned to thelocality occupied before initiating the movement. After dispersal, fledglings' positions(n = 556) occurred in (1) second growth and sapling stage sites at the edge of forested areas [52%], (2) gypsy moth (Lymantria dispar) damaged deciduous forest [21.8%], (3)Virginia pine (Pinus virginianus) forest that had a heavy understory of young deciduous trees and an open canopy [15.6%], and (4) mature mixed forest [10.6%]. Most fledglings(73%) left the Marine Base in September at the mean age of 81 days. After finishing breeding, adult Wood Thrushes underwent molt that extended from late July to early October. Flight-feather molt lasted on average 38 days and may have impaired flight efficiency in some individuals. Of 30 observed adults, 15 molted in the same area where they nested, and 15 moved 545 to 7290 m from their nesting sites. Molting sites were located in areas with a larger number of pines, less canopy cover, fewer trees with dbh>38 cm, and a denser understory strata than nesting sites (P < 0.1). My data suggest that a conservation strategy that focuses on identifying and protecting nesting habitat in the temperate region, although important, is incomplete at best if the events and needs during the post reproductive and post fledging periods are not considered.

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