246 BULLETIN 121, UNITED STATES NATIONAL MUSEUM. 



B. M. Barnes (1890) has described a large herony, formerly existing 

 in Illinois, in which these cormorants nested with great blue herons 

 and American egrets, all three species building their nests in trees, 

 just as they do in Florida. More recent information on the nesting 

 of double-crested cormorants in Illinois is given us by Mr. Frank 

 Smith (1911). Mr. Arthur H. Howell (1911) describes a recent 

 colony in Arkansas, as follows: 



A large colony, probably the only large one now remaining in the State, breeds 

 in a rookery at Walker Lake, Mississippi County, in company with great blue 

 herons and water-turkeys. When I visited this rookery the first week in May, 

 1910, 1 found the cormorants sitting on their nests in the tops of the tall cypresses 

 growing in the lake. The nests, of which there were between 100 and 200, 

 were placed in crotches either close to the trunks or some distance out on the 

 limbs and were compactly built of green cypress twigs with a few strips of bark 

 as a lining. Most of the nests examined contained three or four bluish eggs, 

 but in one were four little naked coal-black cormorants a few days old. The 

 number of nests in a single tree varied from 1 to 6 — usually 3 or 4 — and in many 

 instances the cormorants shared the tree with several great blue herons. Speci- 

 mens taken in tliis colony are referable to the northern form, and this is probably 

 the southern limit of its breeding range. 



Mr. P. A. Taverner (1915) found a colony of about 30 pairs near the 

 Gaspe Basin in Quebec, where the nests were built in trees, mostly 

 small birches, growing from the top and upper face of a bluff over- 

 looking the sea at a height of about 150 feet, a most unusual situation. 



Eggs. — The double-crested cormorant lays ordinarily three or four 

 eggs, frequently five, rarely six, and I have taken one set of seven. 

 They varj^ in shape from elongate ovate to cylindrical ovate. Their 

 color is very pale blue or bluish white, more or less concealed by a 

 white calcareous coating which is thinner than in some other sjjecies, 

 and they are often badly soiled or nest stained. 



The measurements of 40 eggs in the United States National Mu- 

 seum and the writer's collections average 61.6 by 38.8 millimeters; 

 the eggs showing the four extremes measure 65.5 by 40, 63 by 43, 

 56 by 38, and 57.5 by 36.5 millimeters. 



You7ig. — The young when first hatched are purplish black in 

 color, naked, blind, and helpless. Their downy covering begins to 

 grow when they are about 10 days old, and at the age of about three 

 weeks they are fully covered with thick, short, black down. The 

 plumage appears first on the wings and scapulars; the wings and 

 tail are practically fully grown before the body plumage is fairly 

 started, which does not appear until the bird is fully grown; the 

 head and neck are the last porticms to become feathered when the 

 bird is about six weeks old. A populous colony often contains young 

 birds of all ages from naked helpless chicks to full sized birds, and 

 presents a most interesting, if not an attractive, picture. Such a 

 colony is the filthiest place imaginable, for no other birds can equal 



