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David Sibley

Intergradation between Mexican Duck and Mallard in Arizona

The Mexican Duck was formerly considered a species (Anas diazi), and is currently lumped with Mallard (as subspecies Anas platyrhynchos diazi), but recent DNA studies suggest that Mottled Duck (not Mallard) is its closest relative (McCracken et al. 2001). Whatever its genetic background, it is clear from field observations that Mexican Ducks and Mallards interbreed […]

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Two new events coming up this month

11 May 2011, 6:00 to 8:30 PM – Lecture at Boston Public Library, Boston, MA Sponsored by the New England Forestry Foundation. I’ll be talking about the history of forests and bird populations in New England, and the critical need for young forest, shrubland, and grassland. With a book-signing after. Boston Public Library, 700 Boylston St, Copley Square, Boston,

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Dark-fronted Cliff Swallows in Louisiana and Mississippi

It’s time to revisit the variation in Cliff Swallows along the Gulf Coast – with dark-fronted Cliff Swallows nesting in southern Mississippi and Louisiana. I’m continuing to update the Google map of Cliff Swallow forehead colors, thanks to all who have submitted info and especially Susan Epps, who surveyed many locations on the Gulf Coast

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Identifying subspecies by behavior – Savannah Sparrow

Identifying subspecies adds richness to your birding by adding another layer of understanding. What’s more, during spring migration, behavior can offer a quick and fairly reliable clue to use when distinguishing local breeders from migrants. This is simply an extension of a bit of advice often given for identifying shorebirds: to watch for birds around

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