Figure 310. The Rose-breasted Grosbeak is a regular visitant to California, especially in fall and spring, and the CBRC reviewed its records only briefly. This male was photographed on 29 May 1993, during the species’ peak of spring passage, at Aspendell in Inyo County (Larry Sansone).

 

Figure 438. Note the molt limits (contrast between fresh and worn feathers) evident on the wing coverts of this first-spring male Rose-breasted Grosbeak, photographed in May 1990 at Corn Spring, Riverside County (Herbert Clarke).

 

 

 

 

 

ROSE-BREASTED GROSBEAK Pheucticus ludovicianus (Linnaeus, 1766)

Accepted: 14 (100%)	Treated in Appendix H: no
Not accepted: 0	CBRC review: 1972 and 1973 records
Not submitted/reviewed: 1	Large color image: see Figures

This grosbeak’s northern breeding limit extends from extreme southeastern Yukon, northeastern British Columbia, and the southern Northwest Territories east to southwestern Newfoundland. The southern limit reaches from central Oklahoma (rare) east to Maryland and south through the Appalachian Mts. to northern Georgia. The species also breeds casually in the West. Most birds migrate east of the Rocky Mts. and through eastern Mexico to and from wintering grounds that lie on both slopes of Middle America from central Mexico south to northern South America. The species is a rare migrant in the West, occurring primarily in spring except on the Baja California Peninsula, where a preponderance of fall records reflects, at least in part, observer bias. The species winters rarely north to the Gulf states and in Bermuda and the northern West Indies. The winter status is casual across the East, including southeastern Canada, and casual to rare along the Pacific coast (with small numbers of inland records) north to southwestern British Columbia. Extralimital records extend to central and southeastern Alaska (Gibson et al. 2003), the Islas Revillagigedo, Greenland, and Europe.

California’s first Rose-breasted Grosbeak was a one-year-old male collected on 5 August 1891 in Quincy, Plumas County (Grinnell 1931, MVZ 57969). During a 1 July 1897 visit to a fruit orchard at Myers Ranch on the Eel River in Humboldt County, C. H. Gilbert (1916) encountered a “considerable colony” of Rose-breasted Grosbeaks, the species being “so abundant . . . as to be a pest.” Gilbert secured the heads of several birds that had been killed by farm hands, and their accession into the collection at Stanford University was published by McLain (1898). Given that Grinnell (1902) affirmed that “portions of these specimens are still preserved and re-examination confirms the original record as made by R. B. McLain,” we demur to the recent suggestion by Hunter et al. (2005) that this event might actually have involved Black-headed Grosbeaks. The specimens’ whereabouts are unknown.

Rose-breasted Grosbeaks were little reported for several decades, but with sharp increases in field effort and expertise in the 1960s and early 1970s, migrants were found to occur regularly across the state during both spring (6 April–14 July, peaking late May to mid June) and fall (17 July–11 December, peaking late September to late October). As a measure of the species’ relative abundance, note that Richardson et al. (2003) reported records of 274 spring and 169 fall migrants on Southeast Farallon Island between 1968 and 1999, and P. W. Collins (in litt.) had records of 91 spring and 54 fall migrants on the Channel Islands as of February 2006.

Very few Rose-breasted Grosbeaks have been found overwintering in the state’s interior, but small numbers do so regularly along the coastal slope, outnumbering Black-headeds at this season. The latest record of a wintering bird is of one in Santa Barbara, Santa Barbara County, through 25 April 1979 (Lehman 1994). Some records of suspected early spring migrants in late March and April may pertain to birds that wintered locally.

During the twentieth century, Rose-breasted Grosbeaks were considered very rare or casual in California during the summer months, but reports from June and July (the summer reporting period for NAB) have increased markedly since 2000. Although most June records undoubtedly represent late spring migrants, and many July/August records involve late spring or early fall migrants rather than birds attempting to oversummer, the numbers recently tallied during these months are noteworthy nevertheless, and this buildup may presage expansion of the species’ normal breeding range (NAB 58:598). The summer reporting periods of 2000 and 2001 both yielded totals of at least 40 birds in the state (NAB 54:421, 424; NAB 55:481, 484), and in 2004 this number ballooned to at least 69 (NAB 58:598, 602). Roughly three-quarters of recent summer-period reports come from the northern half of the state, where all but a few are typically found along the coast. Summer-period reports from southern California are split almost evenly between coastal and inland locales.

Rose-breasted Grosbeaks pair infrequently with Black-headeds on the Great Plains (e.g., West 1962, Rising 1983), and single records of such mixed pairings exist from both Arizona (Corman and Wise-Gervais 2005) and northwestern Baja California (NAB 55:486). In San Diego County, a male Rose-breasted with begging young and a female of unknown species were observed in El Cajon from 29 July to 10 August 1969 (AFN 23:696); a male Rose-breasted was paired with a female Black-headed at Pine Hills on 14 June 1994 (Unitt 2004); and a male Rose-breasted was associating with a nesting pair of Black-headeds in the Laguna Mts. on 8 June 1997 (Unitt 2004). Rosenberg et al. (1991) stated, “a pair [of Rose-breasted Grosbeaks] is reported to have nested [in 1977] at Lost Lake Resort near Vidal” in Riverside County. A male Rose-breasted present 14 June–10 July 1984 at Montaña de Oro State Park, San Luis Obispo County, was seen copulating with a female Rose-breasted (AB 38:1063; not a female Black-headed as reported by Small 1994), but nesting was not documented. A male Rose-breasted and a female Black-headed successfully fledged young in Tilden Regional Park, Contra Costa County, 1 June–8 July 1992 (AB 46:1176). Birds suspected to be of mixed parentage are occasionally encountered in the field; for example, four records of males on Southeast Farallon Island (Richardson et al. 2003) and one of a male in Tustin, Orange County, 17–18 May 1983 (Hamilton and Willick 1996).