Figure 155. The first California record that the CBRC endorsed as pertaining to an Iceland Gull (sensu stricto) refers to this adult, which was present from 30 December 1984 to 18 January 1985 at Bodega Harbor, Sonoma County. In this photo, taken on 13 January, note the bird’s rounded head, relatively short, slender bill, and long wings with very pale flight feathers (1985-007; Jerry Oldenettel).

 

Figure 156. California’s second accepted Iceland Gull refers to this first-winter individual seen during January 1986 near San Diego, San Diego County. In addition to structural features comparable to those shown by the Bodega Bay adult, note this bird’s very pale plumage with fine brown markings on the wings and underparts. This photograph was taken on 20 January at the Otay Mesa dump (1986-015; Arnold Small).

 

Figure 157. One of many California records of putative Iceland Gulls involves this first-winter bird, photographed on 19 February 1999 in Alviso, Santa Clara County. Evaluation of such birds is hindered by uncertainties of morphological overlap and species limits in the Iceland/Kumlien’s/Thayer’s Gull complex (1999-074; Michael M. Rogers).

 

 

 

 

 

 

 

 

ICELAND GULL Larus glaucoides Meyer, 1822

Accepted: 2 (10%)	Treated in Appendix H: yes
Not accepted: 19	CBRC review: all records
Not submitted/reviewed: several	Color image: none

This gull breeds in coastal Greenland (L. g. glaucoides), on [southern] Baffin Island, and in northern Quebec (L. g. kumlieni), with recent breeding of apparent kumlieni in Greenland (Boertmann 2001). The very pale L. g. glaucoides winters from southern Greenland and Iceland to Scandinavia and the British Isles. Grayer kumlieni winters regularly from Labrador south to North Carolina and west to the Great Lakes region. The AOU (1998) recognized no verified North American records of glaucoides but listed extralimital occurrences of kumlieni from places as distant as Florida, Texas, British Columbia, and western Europe.

Perhaps no species has caused the Committee greater consternation than the Iceland Gull (see Heindel and Garrett 1995:28–30, Erickson and Hamilton 2001). Problems stem in large measure from consideration of Thayer’s Gull (L. thayeri), which breeds in arctic Canada and, at least formerly, northwestern Greenland—north and west of the Iceland Gull’s range—and winters mainly along the Pacific coast. Taken together, these taxa reportedly exhibit a cline of darkening wingtip coloration from east to west (Weber 1981), and L. thayeri and L. g. kumlieni reportedly interbreed freely on Southampton Island (Gaston and Decker 1985). Snell (2002) reported no assortative mating wherever the breeding ranges overlap (eastern Baffin Island, eastern Southampton Island, and Digges Sound) and recommended that only one species be recognized. Treatment of thayeri and kumlieni as distinct at the species level (AOU 1973, 1983) rests almost entirely on the work of Smith (1966), which Snell (1989, 1991) discredited. Note, however, that a detailed study of presumed kumlieni wintering in Newfoundland tended to support—or at least not contradict—Smith’s conclusions (Howell and Mactavish 2003). The AOU (1998:190) suggested that thayeri “is now generally regarded as a distinct species,” but the Thayer’s/Iceland complex is often treated as conspecific (e.g., Beaman 1984, Godfrey 1986, Sibley and Monroe 1990:256, Howell and Webb 1995, Gibson and Kessel 1997, Beaman and Madge 1998, Pittaway 1999, Liebers et al. 2004; but see Burger and Gochfeld 1996). One point of universal agreement is that additional taxonomic work is warranted (e.g., AOU 1998:190), although the prospects for a satisfying resolution are less clear (e.g., Howell 1998).

However the three forms are ranked taxonomically, an observer seeking to identify an extralimital individual conclusively and document the record adequately must overcome certain challenges. Large gulls show substantial intraspecific plumage and structural variation, and this is true for Thayer’s and Iceland Gulls. One pitfall familiar to California observers is that feather bleaching causes some thayeri to resemble kumlieni by late winter and spring (see Howell 2001b). Consider also that hybrid confusion is not limited to putative crosses within the Thayer’s/Iceland complex. For example, a Herring Gull × Glaucous-winged Gull hybrid can be very difficult to distinguish from a Thayer’s Gull (Howell and Corben 2000a) or even kumlieni (Howell 2002b, Howell and Mactavish 2003). Finally, in considering the possibility of an adult Iceland Gull, one must be sure to eliminate the smallest individuals of L. hyperboreus barrovianus (see Mactavish 2002:195), the only subspecies of Glaucous Gull recorded with certainty in California (Banks 1986; see also Patten et al. 2003).

California’s only CBRC-endorsed records of the Iceland Gull refer to a widely seen adult present from 30 December 1984 to 18 January 1985 at Bodega Harbor, Sonoma County (Figure 155), and to a first-winter bird that commuted between Otay Mesa and San Diego Bay, San Diego County, 17–26 January 1986 (Figure 156). Both birds showed phenotypic extremes apparently well outside the range of Thayer’s Gull (see Lehman 1980, Zimmer 1991, Howell and Elliott 2001). See also Appendix H.