THE BROAD-WINGED HAWK. 245 



Besides the different species of trees already mentioned, they nest in 

 maples, poplars, black walnut, beech, chestnut, hemlock, different kinds of 

 pines, oaks, and birches. In the northeastern parts of their breeding range 

 birdies, especially the yellow birch, seem to be most often selected for nest- 

 ing purposes. 



Ordinarily the nest is lined only with thin scales of bark, that of the 



J / 



yellow pine perhaps predominating. Sometimes green fir and other leafv 

 twiys and the fine inner bark of the white cedar is added to the liniiur. 



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Their nests are most often found in the more extensive woods near water 

 and in swamps, and much less frequently in the more open and culti- 

 vated sections. The Broad-winged Hawk is only a summer resident north of 

 about latitude 36, migrating in straggling bodies during September and 

 October to their winter homes in central and northern South America, mov- 

 ing sometimes together in quite large numbers and returning north in March 

 and April. 



Their food consists to a great extent of small rodents, such as mice, 

 gophers, and squirrels; shrews, small snakes, frogs, grasshoppers, beetles, 

 larva; of insects, and very rarely small birds. It is one of the most harm- 

 less of our Raptores and of great benefit to the fanner. It is a late breeder; 

 in the more southern portions of its range nidification begins about the 

 second week in April and correspondingly later northward. In the New 

 England States, northern New York, Pennsylvania, Iowa, and Minnesota, 

 generally in the latter half of May, and in New Brunswick and the south- 

 ern portions of Canada about the beginning of June and sometimes later. 

 Incubation lasts from twenty-one to twenty-five days, and the eggs are 

 deposited at intervals of one or two days. Both parents assist in incubation 

 and in the care of the young. A single brood is raised in a season. 



The number of eggs laid by the Broad-winged Hawk is usually two or 

 three, very rarely four. Mr. O. C. Poling informs me, however, that in the 

 vicinity of Quincy, Illinois, sets of four are not especially uncommon, and 

 that he found a nest of this species containing five eggs. These vary consider- 

 ably both in shape and markings, sometimes even when taken from the same 

 nest. 



The average measurement of forty-five specimens I find to be 48.5 by 39 

 millimetres. The largest eggs, three in number, one from New Jersey, another 

 from New Brunswick, and a third from Pennsylvania, measure each 52 by 40 

 millimetres. The smallest, from Maine, measures 45 by 38.5 millimetres. In 

 shape they range from short and rounded to elliptical ovate, the greater number 

 being short ovate. 



The ground color of the majority of these eggs is dull grayish white; in a 

 few a faint trace of pale gray green is perceptible, and in rare instances this 

 greenish tint is rather pronounced and readily noticed. In some of the eggs 

 faint, lavender, pearl gray, or ecru-drab shell markings predominate, scattered 

 either in fine dots or irregularly shaped blotches and in variable amounts over 



