Transoceanic Migration Of The Blackpoll Warbler: Summary Of Scientific Evidence And Response To Criticisms By Murray

Document Type

Article

Publication Date

Fall 1995

Published In

Journal Of Field Ornithology

Abstract

The hypothesis that Blackpoll Warblers (Dendroica striata) make transoceanic flights in autumn from the northeastern U.S. and southeastern Canada to South America has been proposed or supported in more than 25 papers by many authors, using many techniques. Murray (1989; unpubl.) has criticized this hypothesis, but cited only a few of these papers and misrepresented much of the information that he did cite. Murray misstated information on the location of the western fringe of the SSE flights, the importance of misidentifications, and the phenology of departures. Murray's comparison of regional mean masses was invalid, because the data sets were heterogeneous and non-comparable. Contra Murray, all radar studies in the area have reported directed flights of birds identified as songbirds towards the SSE over the western North Atlantic Ocean. Under Murray's alternative hypotheses, the entire continental population of the species would be concentrated into the coastal plain of the southeastern U.S., but he has cited only two specific records for this entire area. The general statements of status that he cited are outdated, unreliable, and/or undocumented. In contrast, Nisbet (1970a) and McNair and Post (1993a) cited numerous published and unpublished records for this area, including McNair and Post's own extensive field work. These data show that the species is scarce to rare in this area, decisively refuting Murray's hypotheses.

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