Page:The Zoologist, 4th series, vol 6 (1902).djvu/398

338 the able article, "On Anser erythropus and its Allies," in the current issue of the 'Ibis' (cf. 'Ibis,' 1902, pp. 269–275 ).

On studying this subject later, I found that there was much diversity of opinion amongst authorities as to the specific validity of Anser gambeli, the bird having been separated from A. albifrons, and so named by Hartlaub as far back as 1852; and, although his diagnosis has been questioned by several ornithologists, there appears to have been no real effort made to settle the point during all these fifty years.

I must confess that when I first examined the series of skins at South Kensington I was much puzzled, and felt that, with such a series, it would be extremely difficult to discriminate between the two species. I may here say that I consider the series in the National Collection to be inadequate and not a representative one, there being but very few specimens, mostly, if not all, in the winter condition of plumage. Although I have examined the series of both birds twice, they have afforded me very little assistance.

Later, I got together my entire series of White-fronted Geese, and have devoted the bulk of the past winter season to a study of this subject. I have been lucky in securing many examples to fill gaps in my series, and have now sixteen carefully selected specimens to work upon, these providing ample material in my judgment for proving two important facts, viz. the specific validity of A. gambeli—it must not be regarded as a subspecies—and its frequent occurrence as a British bird; the whole of my sixteen specimens of the two species having been received from the west coast of Ireland at different times.

Most authorities agree that the chief distinguishing characteristics between A. albifrons and A. gambeli are, the larger and heavier bill, and darker under parts of the latter. I have found other characters which I will state later; but, taking this longer, broader, and generally heavier-built bill as my guide, I could easily separate the two birds, and make a series of ten A. gambeli and six A. albifrons.

Unfortunately, I lack some of the connecting links in the latter bird; I have seen them in years past, and remember them well, but did not secure them, not knowing at the time that I was collecting two species of birds. I shall meet with those