572 KEPOKT OF STATE GEOLOGIST. 



RANGE. North America, from Cuba and Lower California to 

 Labrador and Alaska. Breeds from Maine and Michigan northward. 



Nest, on ground or in trees; of grass. Eggs, 3, bluish white spotted 

 and marked with different shades of brown, 2.85 by 2.01. 



Common migrant throughout the State; locally, a winter visitor or 

 winter resident. They occasionally remain throughout the winter in 

 great numbers, especially on Lake Michigan, and in less numbers 

 along the Ohio River. During winter floods they may be seen about 

 any of the streams of the State. This is the most common gull 

 found in the State, and is known popularly as "Sea Gull." In the 

 Whitewater Valley it is most abundant in February and March, 

 though it is sometimes seen in January, and in October. Mr. J. W. 

 Byrkit notes that its occurrence about Michigan City is irregular. At 

 times they will be very abundant, and then all will disappear for some 

 time. Mr. J. Grafton Parker says in the vicinity of Chicago and at 

 Millers, Ind., they are very common on Lake Michigan in winter. 

 Hundreds of these birds congregate at the outlets of the sewers of 

 Chicago, in the lake. They leave for the north in April, and are 

 found breeding on Isle Royale, Gull Island, Thunder Bay Island, 

 Mich., and other islands in the great lakes, and thence northward and 

 along the Atlantic coast. As has been noted, these gulls frequent the 

 upper Yukon Valley, and are replaced in the lower valley by L. 

 leucopterus. Isle Royale is a well-known breeding ground for these 

 birds. There they gather in great numbers before the ice has 

 gone,t and proceed to build nests, which vary from a hollow in the 

 accumulations on the rocks to a mass of peat-like material, rootlets, 

 moss and grass matted together placed upon the rocks, the gravelly 

 beach, masses of driftwood on the shore, and even upon the rapidly 

 melting icebergs themselves. In these nests the set of eggs, generally 

 three, is laid some time after the first of May. (Daggett in 0. & 0., 

 July, 1890, pp. 99, 100.) These birds suffer much from the plunder- 

 ing of fishermen and eggers. Finally, however, their work is done. 

 What eggs have been left them are hatched, the young reared, and 

 they turn their flight southward. They reach the lower end of Lake 

 Michigan late in September, and occasionally the Ohio Valley early in 

 October. 



12. (54.) Larus delawarensis (ORD). 



Ring-billed Gull. 



Adult in Summer. Similar to the last, but smaller; first primary 

 black, but with a white spot on each web near the end; the second and 

 succeeding primaries tipped with white, and the feathers one after 



