2012-03-24 Borrego Springs Hawk Watch

Swainson's Hawks
Swainson’s Hawk Watch. Borrego Springs, California. San Diego County.

Swainson’s Hawks are long-distance migrants. They spend winters in Argentina, but travel to Western North America to breed. Until 2003 it was believed that all Swainson’s Hawk migration was through Texas and the mid-west, but Hal Cohen, a recent migrant from the mid-west himself, was studying Turkey Vulture movements through Borrego Springs and discovered these hawks were using a migration corridor not previously known. Now people will flock to the Borrego Valley each spring to watch these great birds in the morning, spending the earliest hours dining on four inch long fat White-Lined Sphinx Moth caterpillars. After breakfast, when the sun’s energy has warmed the desert floor, hundreds of these hawks will “kettle” up, rising with the thermal air currents and circling an hour or more before heading north. From a distance it reminds one of a kettle of water starting to boil.

The birds I met on this outing were Swainson’s Hawk, Phainopepla, Black-Tailed Gnatcatcher.

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