COOPER'S HAWK— "CHICKEN HAWK." 39 



mature, become transverse. It is in some of these intermediate 

 stages of plumage that the two species most resemble one another, 

 so much so indeed in some of the specimens before me that were 

 it not for the invariable difference in size, they could hardly be 

 identified. It is true that the largest females of the F. fiisciis 

 grade up closely to the small males of the A. Cooper i, but there is 

 always an easily perceptible difference in size even in the extreme- 

 forms of these. I have further found a good mark of discrimina- 

 tion to be the shape of the tails. In A. ftisciis the end of the tail 

 is even and the outside feathers are as long, if not a shade longer, 

 than the middle ones ; while in A. Cooperi the middle ones are 

 considerably larger than those outside. None of my specimens 

 of this last bird are in the adult plumage, and I question \'ery 

 much whether there is one of this plumage among any of our 

 Canadian specimens. This, though apparently strange, is not so, 

 for out of a great number of specimens oi A. fusciis, procured in 

 man)- widely separated parts of Canada, I have found only some 

 four or five mature birds. The adult Cooper's Hawk is said by 

 those who have taken it to be not only bluish-gray on the upper 

 parts, but of a decided shade of the same color on the breast and 

 sides. For further particulars respecting the plumages of these 

 two beautiful Hawks, I must refer the reader to the appended 

 descriptions under the present and succeeding articles. 



Though rare in Canada, the Cooper's Hawk is resident and 

 tolerably abundant in the United States. The nest is variously 

 constructed. Audubon describes it as composed externally of 

 numerous crooked sticks, lined with grasses and a few feathers. 

 Brewer describes two, both lined with pieces of bark ; one of them 

 was between one-and-a-half and two feet broad, the external layer 

 of sticks hardly an inch thick. The interior of this nest was 

 shallow, " with only a slight depression in the centre, hardly 

 enough to keep the eggs from rolling out." I have seen only a 

 few of the eggs of this bird, and these were not obtained in 

 Canada, although it undoubtedly breeds here. To assist in their 

 identification, I give Dr. Coues' reliable and accurate account of 

 them. This writer says — " The eggs I have examined measured 



