GLAUCOUS-WINGED GULL. 
44. Larus glaucescens. 25 to 27 inches. 
The primaries are the same color as the mantle on this 
gull except that the primaries are tipped with white. They 
breed in large numbers both on the rocky cliffs and on the 
low sandy islands of the Aleutians. On the cliffs large nests 
of seaweed are built, while on the low sandy islands no at¬ 
tempt is made at nest building. 
Nest.- —Two or three eggs are the usual complement, of a 
greenish brown ground color with various shades of brown 
spots, most thickly covered on the larger end (2.75x 2.05). 
Range. —North Pacific coast, breeding from British Colum¬ 
bia northwards, and wintering to southern California. 
SLATY BACKED GULL. 
48. Lams schistisagus. 27 inches. 
This large gull, with its almost pure white head and neck 
and slaty colored back, is one of the prettiest. They often 
nest in colonies with other gulls, building their small mounds 
of seaweed on the higher parts of the islands. 
Nest. —Usually contains sets of two or three grayish colored 
eggs, spotted with dark brown and lavender (2.90 x 2.00). 
Range. —Northern Pacific and Arctic oceans. 
