Geographic Variation
Broad geographic variation in plumage polymorphism and bill length size is well documented (Salomonsen 1965, Van Franeker and Wattel 1982, van Franeker 1986, Hatch 1993). With rare exception, boreal fulmars of the ne. Atlantic are light-morph birds (van Franeker and Wattel 1982, van Franeker and Luttik 2008), yet in the high arctic are predominantly dark or of intermediate shade, although most breeders on ne. Baffin I. are light (Fig. 2, Appendix 1). Variation in the Pacific is striking in that there are greater extremes of shade—a lighter light morph and darker dark morph—than occur anywhere in Atlantic. Moreover, the latitudinal distribution of color morphs is roughly reversed between Pacific and Atlantic (Fig. 2). In the North Atlantic, bill length and body size tend to increase in a clinal manner from the high arctic south to the boreal zone (Van Franeker and Wattel 1982). Bill length is intermediate in the Pacific, where the bill is more slender. Some Pacific populations are notably small (Appendix 2; see also Measurements: mass, below)
Subspecies
Three subspecies, following Jouanin and Mougin (1979). Although some authorities have questioned the existence of two subspecies in the Atlantic Ocean (e.g., Cramp and Simmons 1977, van Franeker 1986), Salomonsen (1965) and Van Franeker and Wattel (1982) argued that northern (high arctic) and southern (low arctic) populations could be diagnosed. Size varies between sexes, with females averaging smaller (Van Franeker and Wattel 1982), so subspecific comparisons must be made with properly sexed birds. Apparent divergence in genetic barcode led
Kerr et al. (2007) to suggest that Atlantic and Pacific taxa are distinct species.
F. g. glacialis (Linnaeus, 1761). Includes
Procellaria grönlandica Gunnerus, 1767;
P. cinerea Gunnerus, 1767;
P. hyemalis Brehm, 1824;
P. hiemalis Brehm, 1831;
P. melanonyx Nilsson, 1835;
F. g. minor (Kjärbölling, 1854);
P. borealis Brehm, 1855; and
F. g. communis (Brehm, 1866). Largely restricted to the Arctic Ocean, where it breeds on Baffin I., ne. Greenland, Spitsbergen, Franz Josef Land, and n. Russia [type locality = Spitsbergen,
fide Mathews 1934]. Polymorphic, with a dark morph predominant in many populations; averages small, with the bill short and rather wide.
F. g. auduboni Bonaparte, 1857. Largely a n. Atlantic species, where it breeds in ne. Canada, w. Greenland, Iceland, Jan Mayen, the United Kingdom, and locally in nw. Europe [type locality = Newfoundland]. Light morph only; averages large, with the bill long and rather wide.
F. g. rodgersii Cassin, 1862. Includes
F. g. pacificus (Audubon, 1839);
F. g. glupischa Stejneger, 1884; and
F. g. columba Anthony, 1895. Restricted to the Pacific Ocean, where it breeds in the n. Pacific on the Commander and Kurile Is. and, in the United States, the Aleutian and Pribilof Is. [type locality = n. Pacific Ocean,
fide Deignan (1961)]. Polymorphic, with populations largely mixed; body size small to intermediate, with the bill rather slender.
