186 NEW YORK ZOOLOGICAL SOCIETY. 
GROUP IX.—HAWK OWLS, Survia. 
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, Surmia ulula caparoch (Miull.). 
It is interesting to note that this increase in dark markings 
in American birds when compared with their congeners in the 
Palearctic 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 off, 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, Speotyto. 
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. But even 
