This Gull is very like the preceding except that the primaries are the same color as the mantle, and are tipped with white. Length about 27 inches. Not so northerly distributed a bird as the previous ones, and consequently better known. They breed in large numbers both on the high rocky cliffs of the islands along the coast and on the low sandy islands of the Aleutian Chain. On Copper Island they breed on the inaccessible cliffs overhanging the water. As in the case of the Iceland Gull, when the nests are on the cliffs, a large nest of seaweed is made, whereas if they are on the ground, especially in sandy places no attempt is made at nest-building. The eggs have a greenish brown ground color and dark brown spots. Size 2.75 × 2.05. Data.--West Coast of Vancouver Island. June 20, 1896. Three eggs; nest made of seaweed. Located on a low ledge. Collector, Dr. Newcombe. 45. KUMLIEN'S GULL. _Larus Kumlieni_. Range.--North Atlantic coast, breeding in Cumberland Sound and wintering as far south as Long Island. This bird differs from the Glaucous-winged only in the pattern of the gray markings of the primaries and in having a little lighter mantle. It is quite common in its breeding haunts where it places its nest high up on the ledges of the cliffs. The eggs are not different apparently from glaucescens. 46. NELSON'S GULL. _Larus nelsoni_. Range.--Coast of Alaska. Plumage exactly like that of Kumlien Gull and questionably a new species. The nests and eggs are not to be distinguished from the preceding. [Illustration 044: Iceland Gull. Glaucous-winged Gull.] [Illustration: Pale greenish brown.] [Illustration: left hand margin.] Page 43 47. GREAT BLACK-BACKED GULL. _Larus marinus_. Range.--North Atlantic on both the American and European sides; breeds from Nova Scotia northward and winters south to the Great Lakes and the Middle States. The largest of the Gulls (thirty inches long) and unlike any other. The mantle is dark slaty black, and the primaries are black with white tips. The bill is very large and powerful and quite strongly hooked. They are quite abundant birds in their range, and are very quarrelsome, both among themselves and other species. They do not breed in as large colonies as do the other Gulls, half a dozen pairs appropriating a small island to the exclusion of all other birds. They are very rapacious birds and live to a great extent, especially during the breeding season, upon the eggs and young of other birds such as Ducks, Murres and smaller Gulls. They place their nests upon the higher portions of sandy islands. They are made of grasses and seaweed. The three eggs are laid early in June; they are grayish or brownish, spotted with brown and lilac. Size 3.00 × 2.15. Data.--South Labrador, June 21, 1884. Three eggs. Nest on a small island off the coast; of grasses and moss. 48. SLATY-BACKED GULL.--_Larus schistisagus_. Range.--North Pacific and Arctic Oceans.