Introduction

Adult Yellow-billed Magpie, Pleasant Grove, CA, February.

Figure 1. Distribution of the Yellow-billed Magpie.

One of the few truly endemic bird species of California, the Yellow- billed Magpie is a conspicuous resident of open oak woodlands. Found primarily in the Central Valley, the southern Coast Ranges, and the foothills of the Sierra Nevada, this bird generally nests in loose colonies of 3 to 30 pairs, although some nest solitarily. Its large, domed stick nests are conspicuous features of nesting colonies.

Although this magpie has been the subject of several detailed studies of social behavior and ecology, gaps remain in our knowledge of its dispersal, vocal communication, development, evolutionary history, systematics, and relationships to the closely related Black-billed Magpie, now divided into polytypic paleactic (Pica pica) and monotypic North American (P. hudsonia) forms. The Yellow-billed Magpie and North American Black-billed Magpie are more similar in vocalizations and social behavior than either is to Eurasian subspecies of Magpie. Coues (1903) suggested that the persistence of the yellow-billed form in California was a “perpetuated accident.”

This species was named by John James Audubon in 1837 (as Corvus nutalli, [later nuttalli]) in honor of ornithologist Thomas Nuttall, who collected specimens near Santa Barbara, California.

Much of our knowledge concerning the behavior of this species comes from studies done at Hastings Reservation in central coastal California by Nicolas Verbeek (1972a, 1972b, 1973), Mark Reynolds (1990), and Ginger Bolen (1991, 2000). Currently there is considerable conservation concern about this species related to its vulnerability to West Nile virus (Crosbie et al. 2008).