Figure 98. Since the 1994 incursion of Harris’s Hawks into California, the CBRC has tended to accept records of this species from the Colorado Desert—and some from farther north and west in the state’s interior—as pertaining to natural vagrants. The bird’s popularity among falconers, however, fuels skepticism about the legitimacy of records from most parts of the state, including the southern coast. As an example, the Committee did not endorse the natural occurrence of this adult, photographed on 11 December 1994 as it perched on a light standard at the University of California, Irvine, Orange County (2003-018; Robert A. Hamilton).

 

Figure 209. Eight Harris’s Hawks found on 15 April 1994 at Borrego Springs in San Diego County heralded an incursion that brought more than 30 of these birds to California—the state’s first acceptable records in three decades. This adult was photographed at Borrego Springs in January 1995 (1996-080A; Herbert Clarke).

 

 

 

 

 

 

HARRIS’S HAWK Parabuteo unicinctus (Temminck, 1824)

Accepted: 45 (82%)	Treated in Appendix H: no
Not accepted: 10	CBRC review: selected pre-1980 records and those from 1994 through present1
Not submitted/reviewed: 22	Large color image: see Figures

This hawk is a widely distributed resident of South America and Middle America, including most of the Baja California Peninsula. Its range includes southerly parts of Arizona, New Mexico, and Texas, and the species occurs casually elsewhere in the southern and central United States. Assessing the legitimacy of extralimital records is complicated by this attractive hawk’s enduring popularity among falconers and others who keep raptors. The AOU (1998) questioned the origin of birds recorded in Iowa, Ohio, and Florida (several). Some records from these states could involve legitimate vagrants, but it bears noting that similarly questionable extralimital records exist from several other states.

Harris’s Hawk has a storied history in California (Patten and Erickson 2000). Pioneering natural historians found the species along the Arizona side of the Colorado River during the 1850s, but none was found in California until 6 November 1896, when a first-fall male was collected in San Diego, San Diego County. Grinnell (1914) did not record any Harris’s Hawks during extensive surveys along the Colorado River in the early 1910s, but shortly thereafter the species bred at several locales in the lower Colorado River Valley and Imperial Valley (Wiley 1917, Bancroft 1920). Grinnell and Miller (1944) considered this hawk “locally common” by the early 1940s, but by the mid 1960s the state’s breeding population had been extirpated (Garrett and Dunn 1981, Rosenberg et al. 1991).

In 1979, various agencies initiated reintroduction of Harris’s Hawks to the lower Colorado River Valley (Stewart 1979, 1982; Walton et al. 1988). Captive birds were released annually from 1979 to 1987, with the first pair fledging young in 1983 and breeding success extending to three pairs by 1986 (Walton et al. 1988, Rosenberg et al. 1991). The population never became viable, however, and augmentation was discontinued in 1989. But just as Harris’s Hawks had in the past, the species staged an incursion into southeastern California and adjacent Baja California in 1994 (Bednarz 1995, Massey 1998, Patten and Erickson 2000). Evidence of extralimital dispersal was noted across much of the continent’s interior in 1994 and 1995 (NAB 49:49, 65, 69, 82, 153, 163, 166, 173, 178). During this period, birds were recorded as far north in California as the Victorville area in San Bernardino County and as far west as Santee in San Diego County. Scattered individuals also occurred around the Salton Sea and elsewhere, and breeding was documented near Boulevard in San Diego County (Unitt 2004, including a 12 July 2000 photograph of a juvenile).

Harris’s Hawk is very popular among falconers and others who keep raptors. A 10 March 2005 query of the International Species Information System yielded listings of 113 birds at zoos and other participating institutions in North America, including seven in southern California, one in Fresno County, four in Arizona, two in Oregon, and one in Washington. The photograph of a bird at Ramona, San Diego County, on 11 October 2004 (after the cutoff date for this book) shows that it was wearing jesses. The CBRC cannot exclude the possibility of an escapee in most instances, but it seems relevant that Harris’s Hawk has been expanding its range in southeastern Arizona (Bednarz 1995) and has become more tolerant of suburbia there (Dawson 1998). Moreover, the sheer number of birds recorded in California in 1994 and 1995 (more than 50; Patten and Erickson 2000) argues for a natural influx. Only a few of these birds persisted for longer than a few years: at Borrego Springs and Boulevard in San Diego County (Unitt 2004), and around Leyes de Reforma in north-central Baja California (Erickson et al. 2001, NAB 58:437).

¹Off the review list 1988–1993

²The CBRC’s treatment of multi-year Harris’s Hawk records under a single CBRC record number is atypical.

 

[WHITE-TAILED HAWK Buteo albicaudatus Vieillot, 1816 – see hypothetical section]