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Friday, October 24, 2014

On Raptors, Identification, and Physics


One of the joys of working at and visiting Tejon Ranch is the large number of raptors that occur here throughout the year.  Their diversity and activity tends to peak in the fall and winter when Tejon Ranch's large densities of California ground squirrels (Otospermophilus beechyi) provide abundant prey. Golden eagles, red-tailed hawks, ferruginous hawks, prairie falcons and of course California condors (technically not a raptor) are featured birds.  

Sometimes, it can be difficult to tell which species you are observing because soaring birds appear small, even in binoculars. With a little bit of practice, however, one can begin to notice patterns in the bird's silhouette as well as field marks. Here are a few examples of tips you can use to identify a few of the raptors that may be encountered on Tejon Ranch:

Red-tailed Hawk
Photo courtesy of Alan Vernon. Accessed via Wikimedia Commons http://commons.wikimedia.org/wiki/Buteo_jamaicensis#mediaviewer/File:Red-tailed_Hawk_%28Buteo_jamaicensis%29_in_flight.jpg. Remixed by Scot Pipkin
 

Golden Eagle


Ferruginous Hawk
 

Rough-legged Hawk


The incredible diversity of raptors on Tejon Ranch keeps visitors and researchers looking skyward. Add the occasionally ferocious winds over the Tehachapi Range and one can spend an enjoyable afternoon watching the raptors ride the currents and updrafts.  This  video from the New York Times sheds a little light on the tricks these amazing aerialists use to keep from crashing.