206 LIFE HISTOEIES OP NORTH AMERICAN BIRDS. 



"The Buzzard returns year after year to tlie same nest, but is said not to 

 breed a second time the same year if the eggs are taken. When the eggs are 

 very much incubated she sits very close."' 



The eggs are usually from two to four in number, generally three, and 

 according to Seebohm the ground color varies from milky blue to a pale red- 

 dish white. They are blotched, streaked, spotted, or clouded with rich brown 

 surface spots and pale lilac shell markings. There is considerable variation in 

 both size and color, some specimens being spotless. They also vary consid- 

 erably in shape; some are said to be almost round, others oval, some elongated, 

 and, more rarely, elliptical. Their size is given as varying from 57.2 to 50.8 

 millimetres in length by 48.3 to 41.9 millimetres in breadth. 



The U. S. National Museum collection contains a series of eighteen eggs 

 whose average measurement is 55.5 by 44.5 millimetres. The largest of these 

 measures 58.5 by 47, the smallest 52 by 44 millimetres. None of these eggs 

 are figured, as this species does not breed on the North American continent. 



71. Buteo borealis (Gmelin). 



RED-TAILED HAWK. 



Falco horecdis Gmelin, Systema ISTaturfe, i, ii, 1788, 266. 

 Bideo borealis ViEiLLOT, Nouveau Dictiouaire, iv, 1816, 478. 

 (B 23, C 351, R 436, C 516, U 337.) 



Geographical range: Eastei-n North America, west to border of Great Plains; 

 occasional in eastern Mexico; Panama (casual?). 



The Red-tailed Hawk is generally distributed, and breeds more or less 

 abundantly in suitable localities in all that portion of the United States east 

 of the Mississippi River. West of this stream it occurs sparingly in northern 

 Louisiana, and more frequently in Arkansas, the eastern portion of Texas, 

 and in the Indian Territory, Kansas, Nebraska, North and South Dakota. 

 It is fairly common throughout the area indicated, excepting Florida and 

 the Gulf coast generally, where, although very common in winter, it can, 

 from our present knowledge at least, be considered only as a rare summer 

 resident. 



North of our border it is found throughout the southern parts of the 

 Dominion of Canada, ranging from Newfoundland, Nova Scotia, and New 

 Brunswick, where along the coast it is generally rare, but common enough, 

 probably, in the interior, through the provinces of Quebec and Ontario, west 

 to Manitoba and the Northwest Territory. Mr. W. L. Bishop found a single 

 nest of this species placed in a large birch tree near Keutville, Nova Scotia, 

 on June 8, 1890, containing two young in the down. He considers it rare 

 in this province. 



' History of British Birds, 1883, Vol. i, pp. 117-122. 



