Figure 283. The Pine Warbler’s rate of detection has steadily increased to where the species is now recorded annually on the coast, most often in winter. This fairly drab bird was photographed on 8 December 2003 in Imperial Beach, San Diego County (2003-176; Matt Sadowski).

 

Figure 405. California records of the Pine Warbler from 1966 to 2003. Records per year increased dramatically in the late 1980s and early 1990s but have since leveled off or even declined. Records that span two calendar years are tallied for both years.

 

Figure 406. Distribution of 69 Pine Warblers accepted through 2003. Most occur along the southern coast, especially in San Diego County, during fall and winter. None has yet been found in the state’s northern third, and very few records come from California’s interior.

 

 

 

 

 

 

PINE WARBLER Dendroica pinus (Wilson, 1811)

Accepted: 69 (76%)	Treated in Appendix H: yes
Not accepted: 22	CBRC review: all records
Not submitted/reviewed: 4	Large color image: see Figures

This pine specialist’s northern breeding limit extends from southeastern Manitoba east to southern New Brunswick. The southern limit extends from southeastern Texas east to Florida, where the widespread and partially migratory D. p. pinus is replaced by resident D. p. florida. The species winters in the southern part of the breeding range and a bit farther south, to southern Texas, rarely reaching northeastern Mexico and Bermuda. It winters almost annually at feeders in the Canadian Maritimes and New England, less frequently in the southern Great Lakes region. In Canada, records of vagrants extend west to southwestern Alberta and north to southern James Bay. In the West, the species occurs casually during migration and winter, including several winter records from New Mexico, seven winter records from Arizona (Rosenberg 2001), a winter record from Idaho (NAB 58:203, 230), a fall record from southern central British Columbia (NAB 60:126, 274), a fall record from southwestern Oregon, and four fall/early winter records from northwestern Baja California (NAB 56:110; 58:149; 60:288, 289; P. A. Gaede photos). Vagrants have also reached Greenland and Mona Island, off Puerto Rico.

California’s first Pine Warbler, a first-fall male, was collected on 22 October 1966 in the Tijuana River valley, San Diego County (Bevier 1990). As Figure 405 shows, records remained few until 1983, when the rate of detection rose sharply, perhaps reflecting population gains in the East (Böhning-Gaese et al. 1993, Patten and Erickson 1994). The subsequent decrease suggests that factors other than observer effects (which presumably are important) contributed to the earlier spike. Some of this decline may also be linked to die-offs of Monterey Pines (Pinus radiata) in parts of the state since the early 1990s (see Gordon et al. 2001). San Miguel and McGrath (2005) highlighted the species’ frequent association with mature Canary Island Pines (P. canariensis).

As Figure 406 shows, all but eight of California’s Pine Warblers have been found along the southern and central coast. San Diego County’s 25 records represent more than a third of the state’s total.

The Pine Warbler is almost strictly a late fall and winter visitor to California. About half the records (37 of 69) involve fall vagrants, most between 13 October and 22 November; see also Appendix H. Twice the CBRC has voted to accept a 1 October 1987 record from Riverside, Riverside County, which stands as the state’s earliest in fall. Winter records, with bracketing dates of 9 November and 12 April, account for up all but two of the remaining records (30 of 69) and since 1994 have accounted for roughly three out of every four (15 of 21). Two birds not seen past December (in 1986 and 2003) could have been late fall vagrants. Perhaps they perished or relocated only a short distance from where originally found. El Dorado Park in Long Beach, Los Angeles County, has held Pine Warblers in consecutive winters, but the CBRC has yet to treat any record as pertaining to a returning bird. In spite of the Pine Warbler’s status as a very early spring migrant in the East (e.g., Rodewald et al. 1999), the timing of early April records in 1984 and 2002 accords better with California’s winter records than it does with the state’s two much later records of definite spring vagrants, both singing males: 31 May 1984 at Furnace Creek Ranch, Inyo County, and 5–6 June 1987 at Torrey Pines State Reserve, San Diego County.

Most Pine Warbler records that the CBRC has not endorsed—including two that were initially accepted before re-review—are from before mid October and likely pertain to Blackpoll, Bay-breasted, or perhaps Prairie Warblers. For example, a warbler captured on 19 September 1989 at Modoc NWR, Modoc County, was reported as a Pine, but in-hand photos showed it to have been a Blackpoll. And California’s first wintering Pine Warbler was believed for several days to be a Prairie. Whitney (1983), Kaufman (1990), Hough (1996), and Dunn and Garrett (1997) provided detailed information on identifying these various species.