PRBO Conservation Science
Quarterly Journal of PRBO Conservation Science, Number 141, Summer 2005: Notes and Discoveries from the Field

This diversity of species can indicate abundant food and relatively healthy habitat conditions.


Raptor Watch

Katie Fehring

Executive Director's Column
Return of the Least Bell's Vireo
Mystery Oil Spill
Bird Bio
Eastern Sierra
Seabirds at Vandenberg
Farallon Auklet News Flash

It is a cold May day, and I've been watching this cliff through the scope for several hours without seeing anything move. Sitting on an ashy little mound in the sagebrush, staring at a rock wall, listening to the Sage Thrashers and Brewer's Sparrows sing, I'm trying hard to remain focused now that the thermos of coffee has run out.

Finally I hear the sharp cackling call I've been waiting for: a male Prairie Falcon comes into view, and the larger and browner female calls back to him. The pair is claiming a sheer red cliff marked with thick whitewash streaks. The male flies to her, and they copulate on the top of a large boulder, blending in perfectly with the rock face.

It's exactly what I hoped to see, because my job here is to determine what birds are using the nine kilometers of cliff habitat on this Eastern Sierra ranch. The commotion activates other cliff residents; White-throated Swifts pour out of the cracks and circle at a safe distance. An American Kestrel pair also calls and behaves nervously at their larger falcon cousins' presence. The copulation means this Prairie Falcon pair will likely use the cliff face for nesting, picking a secure ledge where the female will lay four or five eggs directly on the bare rock. Their high perch allows them a clear view of any approaching predators--and of potential meals, Horned Larks and ground squirrels.

When I return a month later, the female sits low on her nest, brooding the small falcon nestlings. The male kestrel is busy bringing a constant stream of lizards for the female to deliver to their hungry kids. Two other cliffs on the ranch are occupied by nesting Common Raven pairs. We have also seen Golden Eagles, Red-tailed Hawks, and Swainson's Hawks using Adobe Ranch. A pair of Long-eared Owls nesting head-high in a willow tree in the narrow riparian strip along Adobe Creek hisses and claps their bills when I check their progress.

Raptors are high on the food chain, and this diversity of species can indicate abundant food and relatively healthy habitat conditions. In addition to raptors and their prey, a wide variety of bird species will be managed for at Adobe Ranch--highlighting the importance of an all-bird monitoring approach to adaptive restoration.

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