NORTH AMERICAN BIRDS. 189 



America, and is familiar to every boy who has been in the fields. Here 

 it may be seen hovering almost motionless in mid air, then suddenly 

 swooping down to the ground, arises again with perhaps a field-mouse 

 in its talons. From this habit it receives the name of Mouse Hawk, 

 although it also preys upon sparrows and other small birds. It is 

 found almost everywhere, though most abundant along streams where 

 the high sycamores whose natural cavities furnish suitable nesting 

 places, but meadows and fields are its retreats when in search of food. 

 It builds no nest, but deposits its eggs in the natural cavities of high 

 trees, often in the deserted holes of woodpeckers, or in crevices in 

 rocks or nooks about buildings. In the West it frequently occupies a 

 deserted Magpie's nest. I have eggs of this Hawk taken from a crev- 

 ice in a stone quarry on the Scioto River, where the birds have nested for 

 years. Boxes on farm barns, provided for domestic pigeons, are often 

 appropriated by the Sparrow Hawk, and it always proves to be a peace- 

 able neighbor. The cavities where the eggs are deposited generally 

 contain no lining. Dr. Merrill examined a number of nests in Mon- 

 tana, and the eggs were deposited in many cases on a slight bed 

 of leaves or grasses or a few chips. 



The eggs of the Sparrow Hawk are four or five, rarely six in num- 

 ber. A series of forty eggs before me exhibit the usual wide diversity 

 of coloration that is to be found in eggs with spotted shells. Most of 

 my eggs are from Ohio, Indiana and Kentucky, while two sets are 

 from California. The ground color varies from a yellowish or cream}'- 

 white to reddish or pinkish-buff; the surface is sprinkled, splashed, 

 blotched, spotted and clouded with shades of chestnut and cinnamon 

 brown, and the markings may be more numerous and heavier at either 

 end, and they may be so confluent as to conceal the ground color. 

 Eight eggs collected near Banning, Cal., April lo, 1884, measure 

 1.28x1.05, 1. 30x1.09, 1.30x1.07, 1.32x1.09, 1.36x1.07, 1.35x1.07; 

 1.36x1.11, 1.38x1.15. The largest eggs I have are from Ohio, taken 

 by Robert lyinton, April 20, four in number. Sizes, 1.37x1.15, 

 1.40x1. 13, 1.38x1.12, 1.44x1.16. The average size of the Sparrow 

 Hawk's eggs is 1.36x1.12. They are usually deposited in April or 

 in the first half of May. 



362. Polyborus cieriway (Jacq.) [423 ] 



Andulioii's Caracara. 



Hab. Northern South America (Ecuador and Guiana) north to the Southern border of the United 

 States, Florida, Texas and Arizona, 



Common to the Southern border of the United States, and known 

 as the Mexican Eagle or Buzzard — intermediate between the Eagles 



