42 BIRDS OF TREY. 



said to lay four eggs, clouded with reddish. It is common 

 also to the north of Europe, if not to Africa. The usual station 

 of these birds is on the outskirts of woods, in the neighborhood 

 of marshes, — situations suited for supplying them with their 

 usual humble prey of frogs, mice, reptiles, and straggling birds, 

 for which they patiently watch for hours together, from daybreak 

 to late twilight. When prey is perceived, the bird takes a cau- 

 tious, slow, circuitous course near the surface, and sweeping over 

 the spot where the object of pursuit is lurking, he instantly 

 grapples it, and flies off to consume it at leisure. Occasionally 

 they feed on crabs and shell-fish. The inclement winters of 

 the high northern regions, where they are usually bred, failing 

 to afford them food, they are under the necessity of making a 

 slow migration towards those countries which are less severe. 

 According to Wilson, no less than from twenty to thirty young 

 individuals of this species continued regularly to take up their 

 winter quarters in the low meadows below Philadelphia. They 

 are never observed to soar, and when disturbed, utter a loud, 

 squealing note, and only pass from one neighboring tree to 

 another. 



The great variation in the plumage of this Hawk has been the 

 cause of considerable controversy. Wilson wrote of the black and 

 the brown phases as of two species, giving them distinct habits. 

 Nuttall, following Audubon, considered the changes from light to 

 dark due only to age. Spencer Baird (in 1S58), Cassin, and Dr. 

 Brewer agreed with Wilson. Later authorities, however, with 

 more material to aid them, have pronounced both views incorrect, 

 and have decided that there is but one species, — that the black is 

 but a melanistic phase. Our systematists now separate the Ameri- 

 can from the European form, giving to the former varietal rank, 

 as its " trinomial appellation " denotes. 



Nuttall does not mention the occurrence of this bird in Massa- 

 chusetts, though Dr. Brewer states that at one time it was abun- 

 dant near Boston, and within more recent years numbers have been 

 captured by Mr. E. O. Damon on the Holyoke Hills, near Spring- 

 field. It occurs within the United States principally as a winter 

 visitor, its chief breeding-ground lying in the Labrador and Hudson 

 Bay district. 



