Cross-seasonal effects in the American Woodcock: Conditions prior to fall migration relate to migration strategy and implications for conservation

Authors: Clayton L. Graham, Tanner Steeves, and Scott R. McWilliams

Year: 2022

Publication: Ornithological Applications

Publication Link:

Keywords: American Woodcock, body composition, fall migration, partial migrant, postbreeding movements, upland gamebird

Abstract: How postbreeding habitat quality and body composition of migratory birds carry over to influence fall migration strategies
and residency merits consideration when creating cross-seasonal conservation plans, especially in breeding
populations that are partial migrants. We assessed the influence of postbreeding habitat quality on departure body composition
and fall migration patterns in a southern New England breeding population of American Woodcock (Scolopax
minor). Woodcock that overwintered near breeding areas (n = 5) had less fat upon capture in fall and used lower quality
habitat during the fall than birds that eventually departed on migration (n = 17). Woodcock that departed earlier were
long-distance migrants that had inhabited higher quality landscapes prior to migration, departed with less or similar fat
stores, stopped over for shorter periods on migration, and arrived earlier on their more southerly wintering areas. In contrast,
woodcock that departed later were short-distance migrants that had inhabited lower quality landscapes prior to
migration yet stored similar or more fat upon departure, stopped over for longer periods on migration, and arrived relatively
late to their more northerly wintering areas. These differences in migration strategies were evident under the same
fall environmental conditions and did not appear related to individuals responding to their own condition as would be
expected if they were classic condition-based carry-over effects. As such, the southern New England breeding population
of woodcock is best categorized as nonfacultative partial migrants (i.e., includes residents, short-distance migrants,
and long-distance migrants) that demonstrate weak connectivity between life stages; such populations are excellent
for the study of the costs and benefits of migration. The stopover and wintering areas used by woodcock in the coastal
mid-Atlantic states deserve conservation and management attention in order to preserve critical habitat throughout
their wintering range.

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