TRANSOCEANIC MIGRATION OF THE BLACKPOLL WARBLER - SUMMARY OF SCIENTIFIC EVIDENCE AND RESPONSE TO CRITICISMS

The hypothesis that Blackpoll Warblers (Dendroica striata) make transo ceanic flights in autumn from the northeastern U.S. and southeastern C anada 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 a nd misrepresented much of the information that he did cite. Murray mis stated information on the location of the western fringe of the SSE fl ights, the importance of misidentifications, and the phenology of depa rtures. Murray's comparison of regional mean masses was invalid, becau se 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 Atlant ic Ocean. Under Murray's alternative hypotheses, the entire continenta l population of the species would be concentrated into the coastal pla in of the southeastern U.S., but he has cited only two specific record s for this entire area. The general statements of status that he cited are outdated, unreliable, and/or undocumented. In contrast, Nisbet (1 970a) and McNair and Post (1993a) cited numerous published and unpubli shed 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.