Monday, April 7, 2014

Couch’s Kingbird

As Erika and I rested at The Rockport Demo Bird Garden and Wetlands Pond, Erika suddenly pointed and said, “Now there’s a different bird!” Our choice was between Couch’s and Tropical kingbirds. Silent birds like this one are very difficult to tell apart. Couch’s Kingbirds have tails that are less notched. Their bills are relatively shorter. They often has brighter olive-green back. Our bird seems to confirm to these field marks. (Banders can often separate them by comparing their culmen-length to wing-length ratios and by the relative length primary five or primary four).

A look in eBird, however, added another clue. The Tropical Kingbird is usually restricted to the lower Rio Grande Valley, while the Couch’s ranges at least to the Rockport area along the Texas coast. eBird did not list the Tropical Kingbird as a possibility for our location.

The first Couch’s Kingbird was discovered by Darius Couch in 1853 and described in 1859. A problem arose thereafter, however, because the bird was “demoted” to subspecies status—just a race of the Tropical Kingbird. Not until 1979, on the basis of their different calls, was the Couch’s Kingbird returned to species status. Due to this hiatus, much confusion exists about just which species older ornithologists studied. Precise details. therefore, are lacking about much of Couch’s Kingbird biology (Brush 1999). In any event, Couch’s Kingbirds range from southeastern Texas across much of eastern Mexico to northern Central America.

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