THE ItEU-SHOULDEllED HAWK. 223 



Incubation lasts about four weeks, and the eggs are deposited at intervals 

 of two and sometimes three days. As said before, the number laid by this 

 species varies from two to six. Sets of three are most frequently found, and 

 are a fair average number. About one set in three contains four eggs. 



In shape these range from ovate to short and rounded ovate, and a few 

 are perfect oval. The ground color varies from a dull white to a pale yel- 

 lowish, and again a pale bluish white. Unspotted eggs are very rare, and 

 even faintly marked ones are not common. The majority are all more or 

 less heavily smeared, blotched and spotted, ..with different shades of reddish 

 brown, fawn color, ecru-drab, vinaceous buff, and pearl gray. Some of the 

 lighter tints are shell-markings. In some eggs the markings are few, but* 

 large and bold; in others they are finer, of smaller size, and more profuse, 

 hiding the ground color to a considerable extent. They are generally irreg- 

 ularly blotched, and in a limited number of specimens these run longitudinally, 

 as in the egg of Swainson's Hawk (figured on PI. 8, Fig. 6). They show an 

 almost endless variety of patterns, and there is practically no difference in 

 this respect between the eggs of this species and its two geographical races, 

 excepting that those of typical Buteo lincatus alleni from Florida are consid- 

 erably smaller, as will be seen hereafter. The shells of these eggs are close 

 grained, finely granulated, and without luster. 



The average measurement of a series of one hundred and seventeen eggs 

 of this species, from various points of eastern North America, is 54.5 by 43 

 millimetres. The largest egg measures 59 by 47, the smallest 51 by 41 mil- 

 limetres. The latter is from Locust Grove, New York, the former from East 

 Hampton, Connecticut, both from Dr. C. Hart Merriam's collection. 



Ten specimens, collected by Mr. J. A. Siiigley, near Giddings, Lee County, 

 in central Texas, give an average measurement of 54 by 44.5 millimetres, being 

 fully as large as eastern specimens. I am inclined to think that though perhaps 

 not referable to typical 13. lineatus, they resemble more closely the eggs of this 

 subspecies than those of the Florida Red-shouldered Hawk. 



The type specimens selected to show some of the various patterns of color- 

 ation, are as follows: No. 12873 (PI. 7, Fig. 1), a single very dark colored egg, 

 was collected by Mr. Robert Ridgway, of the Smithsonian Institution, near 

 Mount Carmel, Illinois, April 1, 1867; No. 21688 (PI. 7, Fig. 2), from a set of 

 four collected by Dr. C. Hart Merriam, near Locust Grove, New York, April 

 24, 1878; No. 23942 (PI. 7, Figs. 3 and 4), two eggs from a set of four, were 

 collected near Giddings, Lee County, Texas, by J. A. Singley, on April 11, 

 1888; No. 23943 (PI. 7, Fig. 5), from the same source and locality, from a set 

 of three, and taken April 16, 1888. 



