Fall and Winter Movements of Newfoundland Graycheeked Thrushes (Catharus Minimus Minimus)

摘要

The Newfoundland subspecies of Gray-cheeked Thrush (Catharus minimus minimus) has declined since the 1980s and degradation of winter habitat has been suggested as a contributing stressor. However, the winter range of this subspecies is not well understood, so we fitted 29 males with archival GPS tags during summer 2016. Four tagged thrushes were recaptured in summer 2017 and, though all tags had missing locations and broken antennae, the data retrieved showed that one thrush wintered in the Sierra Nevada de Santa Marta (SNSM) in northern Colombia, one in the nearby Sierra de Perija in Venezuela, and a third may have settled in the same region. One tag provided locations until April 21 and that thrush was consistently detected within a ~1 ha area through the winter. Locations obtained during fall migration indicated that thrushes travelled to South America via Central America and possibly by directly crossing the Caribbean. Contemporary research indicates that the SNSM is an important migratory stopover for Northern Gray-cheeked Thrushes (C. m. aliciae) but a historical report coupled with our observations suggest winter use of the SNSM and adjacent areas in northern South America by C. m. minimus, though numbers may be lower than during the 1900s.