June 05, 2006

Window birds

132 merlin

During my afternoon work commute, a small falcon slices across the highway view, gray and tawny-red. A male merlin, and it's about time—my first commuting bird of the year! At today's gas prices, this single species cost me several hundred dollars.

Listening to bird CDs means I'm familiar with more songs, but I may be losing command of the ones I know. One morning outside my window I hear four familiar notes but can't place them. Later I realize it's a Carolina chickadee—or is it? Columbia is in the contact area between black-capped and Carolina chickadees, which are almost identical in appearance. From Birds in Missouri and the Cornell Lab of Ornithology:

It may be impossible to identify the species of an individual chickadee by plumage or song near the contact zone.

Where the two species ranges come in contact, the Carolina and Black-capped chickadees occasionally hybridize. Hybrids can sing the songs of either species, or might sing something intermediate.

Fortunately, what this also means is that any chickadee I see beyond 100 or so miles south has to be a Carolina, so I'm sure to add it to my list.


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