Dr. Charles van Riper III

Professor, School of Natural Resources and the Environment
USGS Research Scientist Emeritus  

Sonoran Desert Research Station
125 Biological Sciences East ~ University of Arizona ~Tucson, AZ 85721-125
(520) 626-7027 ~ (520) 670-5100 fax ~ (520) 491-0721 call

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Natural History

Western Yellow-billed Cuckoos (Coccyzus americanus occidentalis) were historically found in riparian habitats throughout western north America.  They currently exist in medium and large riparian habitat patches in California, Arizona, New Mexico, and perhaps Mexico (Halterman 1991).  Formal surveys were begun in Arizona  during summer 1998 to determine the current status of the species and habitat that they are utilizing.  Prior to these surveys, Yellow-billed Cuckoos had been reported along the lower Colorado River (Anderson and Ohmart 1984), the upper San Pedro River in Cochise County (Hamilton and Hamilton 1965), the lower Bill Williams River (Rosenberg et al. 1991), and Sonita Creek in Pima County (Hamilton and Hamilton 1965). They have been also reported incidentally from the Verde, Salt, and Gila Rivers (Anderson and Ohmart 1977, Carothers et al. 1974, Swarth 1914).  Results of these surveys are reported in this web site under DATA.

In the Lower Colorado River Valley, Yellow-billed Cuckoos prefer mature cottonwood-willow stands but will utilize willows and cottonwoods mixed with tall mesquites to a lesser extent.  Foraging birds may be found in stands of smaller mesquite trees and even salt cedar in the southwest, but seldom nest there.  Rosenberg et al. (1991) reports the decline of cottonwood habitats has had a negative effect on this species in the southwest. 

Mature Cottonwood Gallery


Mixed Riparian Forest 






Hosting Beyond The Sidewalks