ANDERSON — THE BIRDS OF IOWA. 183 



Iowa contains a very large series of Snow Geese in the D. H. 

 Talbot collection, mostly collected in the Mississippi Valley. The 

 writer examined and took careful measurements of seventy-eight 

 skins collected in Iowa. The length of wing (from bend of 

 closed wing to tip of longest primary), and the length of bill 

 (chord of the culmen) being the most constant dimensions, were 

 taken as a basis of comparison for determining what proportion 

 might be referred to Chen hyperborea and what to Chen hyper- 

 borea nivalis. Dr. Coues gives the average measurements of C 

 hyperborea z.'A: Length about 25.00; wing 14.50-17-00 ; tail 5.50; 

 tarsus 2 . 73-3 .25; bill 2 . 00-2 .12. Chen hyperborea nivalis — length 

 27.00-31.00 or more; wing 17.00 or more; tail 6.50; tarsus 

 3-00-3.50; bill 2.35-2.65. 



One of the specimens measured was taken at Sloan, Iowa, and 

 all of the others at Whiting, Iowa, from March 7 to April 8, 1885, 

 and March 23 to April 6, 1886. Three specimens had wings 

 measuring less than 15 inches; thirty specimens between 15 and 

 16 inches; seventeen between 16 and 16.50 inches; twenty, between 

 16.50 and 17 inches; and eight over 17 inches, the maximum being 

 17.50 inches. Twenty-six specimens had bill measuring between 

 1 .90 and 2.12 inches {hyperborea); forty-two between 2.12 and 2.35 

 inches (intermediate); and ten over 2.35 inches, the maxinuim 

 being 2.48 inches [nivalis). On the basis of these measurements 

 only ten or twelve per cent of the specimens from Iowa can defi- 

 nitely be considered as Greater Snow Geese, the remainder being 

 the Lesser variety, with every grade of intermediates between . In 

 the face of such perfect intergradation, the attempt to differenti- 

 ate between the varieties seems to be almost a useless refinement. 



57. (169a). Che)i hyperborea nivalis (Forst.). Greater Snow 

 Goose. 



What has been said under the preceding species applies equally 

 to this variety. It appears to be less common in Iowa than the 

 Lesser Snow Goose, but unless birds are captured it is impossible 

 for an observer to distinguish between the two. In Wisconsin, 

 Kundien and Hollister class the Greater Snow Goose as a 

 "migrant, formerly abundant, but now rather rare. ... Of the 

 specimens examined, taken during the past sixty years and mostl}- 

 when the birds were abundant, about one-half are typical of either 



