Figure 281. About half of California’s records of Grace’s Warbler pertain to spring and summer vagrants in the southeastern mountains, and most of the rest are of fall and winter birds near the coast. This sketch, made on 24 February 1996, depicts an individual that wintered from 22 October 1995 to 10 March 1996 at a most unusual location, at an elevation of 5400 ft. at Chilao Flat in Los Angeles County (1996-030; Gerard Phillips).

 

Figure 404. Distribution of 43 Grace’s Warblers accepted through 2003, showing major concentrations at Pt. Loma in San Diego County (10 birds) and Clark Mtn. in San Bernardino County (eight birds). All fall and winter records are from coastal counties and all spring and summer records are from interior counties, with the exception of a 14 June 2003 record from Buckhorn Flat in the San Gabriel Mts. of eastern Los Angeles County.

 

 

 

 

 

GRACE’S WARBLER Dendroica graciae Baird, 1865

Accepted: 43 (86%)	Treated in Appendix H: yes
Not accepted: 7	CBRC review: all records
Not submitted/reviewed: 13	Large color image: see Figures

This pine-dependent warbler breeds from southern Nevada east to southwestern Colorado and western Texas, and south through western Mexico and Central America to northern Nicaragua. Close to California, the species breeds uncommonly in the Spring Mts. of southern Nevada and commonly in the Hualapai Mts. of western Arizona (Phillips et al. 1964), and nesting was recently confirmed in the Cerbat Mts. and Virgin Mts. of northwestern Arizona (Corman and Wise-Gervais 2005). Subspecies graciae—the most migratory of the four subspecies and the only one likely to reach California—breeds in northern Mexico and the Southwest and winters in the highlands of Mexico, including Nayarit, Morelos, and México (Dunn and Garrett 1997). Southern California accounts for the lion’s share of extralimital records, but the species has also been documented in Baja California Sur (NAB 58:287; 59:155, 192; 60:289), central Colorado, western Texas, and Chicago, where on 8 September 2003 the species made its first appearance east of the Mississippi River (NAB 58:76-77, 173).

California’s first Grace’s Warbler was a female collected on 29 October 1966 in the Tijuana River valley, San Diego County (A. M. Craig 1970). Since then, fall vagrants (7 September–29 October) have been recorded 17 times on the coastal slope north to San Luis Obispo County. The 15 winter records (11 September–20 April) are from coastal counties north to Monterey County and include one of a bird that overwintered in 1995/1996 at Chilao, Los Angeles County (elevation 5400 feet). See also Appendix H. Some wintering birds have shown extraordinary philopatry, particularly a male that returned to Montecito, Santa Barbara County, for nine consecutive years during the 1980s. A drop in the frequency of detection along this county’s southern coast since the early 1990s coincided with a large-scale die-off of mature Monterey Pines (Pinus radiata) in the same region (Gordon et al. 2001).

Several Grace’s Warblers have been found during late spring and summer in forests of Yellow Pine (P. ponderosa) or White Fir (Abies concolor) that appear suitable for breeding, and it seems likely that the species eventually will be found breeding in California (see Johnson 1994). At Clark Mtn. in northeastern San Bernardino County, pairs have twice been found in appropriate habitat during the breeding season—on 3 June 1995 (female near a singing male) and 24 May 2003—but nesting remains unconfirmed. Judging the number of singing males has been a recurring problem. The few claims of multiple singing birds on Clark Mtn. have been attributed to lone males covering large territories (see, e.g., Bevier 1990) or possible mimicry by a Yellow-rumped Warbler or other warbler species (see Kroodsma et al. 1983, Payne et al. 1984, van Buskirk 1984).