186 NEW YORK ZOOLOGICAL SOCIETY. 



GROUP IX. — HAWK OWLS, Siiniia. 



The typical Hawk Owl of the Old World is only a casual strag- 

 gler to Alaska, so hardly enters into our consideration, but those 

 members of this species, which in past time took up their life 

 upon our continent, have, through their isolation, changed in color 

 from the excess of white spotting to the prevalence of brown 

 markings, and are deemed worthy of a sub-species — the American 

 Hawk Owl, Siiniia iilula caparoch (Miill.). 



It is interesting to note that this increase in dark markings 

 in American birds when compared with their congeners in the 

 Palaearctic Region, occurs also in the Richardson as compared 

 with the Tengmalm owl, and was formerly thought to form a 

 distinction between snowy owls of the New and the Old World. 



Though typically owl-like in structure the diurnal habits of 

 the Hawk Owl are strongly reflected in its appearance, which is so 

 hawk-like that it is hard to believe that this resemblance is only a 

 parallelism. Curiously enough, this likeness is even apparent in its 

 sudden, shrill scream — unowl-like and recalling the cry of one of 

 the smaller hawks. 



The home of the Hawk Owl is in the fur countries of the 

 north, breeding from Newfoundland to the limit of tree growth. 

 Occasionally it comes as far south as Pennsylvania. It hunts 

 throughout the day and at night retires to some arboreal roost 

 for sleep, like any bird of the day. Its food consists chiefly of 

 mice, but in the more northern parts of its range it feeds largely 

 upon ptarmigan. These grouse exceed the owl in size and weight, 

 so that it is unable to carry them ofif, but is compelled to devour 

 them where they are caught and killed. 



It is not particular as to a nesting place, choosing either a hollow 

 stub, a woodpecker hole or else relining some deserted nest. 

 Three to seven eggs are laid. 



GROUP X. BURROWING OWLS, SpCOtytO. 



These are perhaps the most aberrant of all owls, and, together 

 with Micropallas are found only in the New World. This genus 

 is eminently tropical in its distribution, and its presence in the 

 Nearctic Region is clearly an intrusion from the south, stand- 

 ing in sharp contrast to the other groups, which, from their dis- 

 tribution and congeneric relationship with Old World forms, 

 seem to be more recent emigrants from the northwest. Ikit even 



