FALCONID.E — THE FALCONS. 235 



The average size of the eggs of this bird is 1.56 by 1.94 inches. The 

 color is usually a uniform dull white, but is occasionally tinged with as light 

 bluish shade. They are nearly spherical, though not more so than the eggs 

 of se\'eral .species, and are equal at either end. Their surface is slightly 

 granulated. The number of the eggs varies from three to four, though occa- 

 sionally there are five in a nest. 



The maximum length of the egg of this species is 2.00 inches, the mini- 

 mum 1.85 ; the maximum breadth 1.60, the minimum 1.50 inches. In occa- 

 sional instances I have known the eggs of this species more or less distinctly 

 marked, especially about the larger end, with blotches of a light yellowish- 

 brown. Those most distinctly marked in this manner were taken and iden- 

 tified by Mr. Paine. 



A nest of this Hawk, found by Dr. J. W. Yelie, was built on a poplar- 

 tree, about forty feet from the ground, and was composed of sticks and lined 

 with moss and leaves. There was a small cleared space of three or four 

 rods in extent, in the middle of which the tree stood, and aliout a quarter 

 of a mile from the main channel of the ilississippi Eiver, on Kock Island. 



The Cooper Hawk was found on Mount Tom by Mr. William Street, 

 nesting for the most part in pine or hemlock trees, usually choosing one in 

 a tliick clump. They begin to lay about the first of May, usually depos- 

 iting four eggs. They are very shy, and it is almost impossible to get 

 within shot of them, even when they have young. They rarely molest the 

 poultry -yard, but seem to live chiefly on small birds and animals. They 

 leave tlieir nest at once whenever it is approached, and will not return until 

 the intruder has gone. 



The var. mexicanus, originally described by Mr. Swainson from Mexican 

 specimens obtained near Eeal del Monte, has been ascertained to cross our 

 boundaries, and is found in all the territory between the Eocky Mountains 

 and the Pacific, as far north as Washington Territory. Dr. Cooper has never 

 met with this Hawk, but supposes its general habits, and esj)ecially those 

 regulating its migrations, closely resemble those of A. cooperi, to which the 

 bird itself, in all but size, is so similar. Dr. Coues speaks of it as a common 

 resident species in Arizona. He states that he has seen young birds of this 

 species, reared by the hand from the nest, become so thoroughly domesti- 

 cated as to come to their master on being whistled for, and perch on his 

 shoulder, or follow him wlieu shooting small birds for their food. They 

 were allowed their entire liberty. Their ordinary note was a shrill and 

 harsh scream. A low, plaintive, lisping whistle was indicative of hunger. 



Dr. Suckley, who met with this bird on Puget Sound, where a specimen 

 was shot on a salt marsh, states that, while soaring about, it resembled in its 

 motions the common Marsh Hawk, or Hen Harrier {Circus hudsonius). 



