182 NEW YORK ZOOLOGICAL SOCIETY. 
tion to the thirteen forms mentioned above, there are more than 
half a dozen kinds of -Screech Owls known to inhabit Mexico, 
none of which cross the southwest border of the United States. 
The habits of all are very similar to those of our eastern bird. 
When wishing to conceal itself, a S¢reech Owl draws its feathers 
close to its body, stands bolt upright, with eyes almost shut, and 
in this posture its remarkable resemblance to a dead branch stub 
is doubtless of great value to it. The illusion is heightened by 
the conspicuous feather ears which stick up like the splintered 
ends of a broken off branch. 
GROUP VII.—GREAT HORNED OWLS, Bubo. 
These are the largest and fiercest of the owls of the United 
States, and are important, both as a conspicuous feature of our 
Avifauna and in their economic relations to man. They are found 
in almost all parts of the North American continent, and show 
adaptive radiation in a most interesting way. Six different forms 
are recognized, but these intergrade and the ranges overlap to such 
an extent that no hard and fast lines can be drawn. 
Considering the Great Horned Owls as a whole, the eastern 
form Bubo virgimianus (Gmel.), which extends from Newfound- 
land and Ontario southward, is clothed with various shades of 
ochraceous-buff and black. In the central west we find a form 
much lighter than our eastern owl; but then, passing northward 
in the interior to the Hudson Bay territory—the land of snow 
and snow-colored creatures—Bubo becomes whiter and whiter, 
until, in the extreme type of the Arctic Horned Owl, we have a 
bird with a plumage of a white ground-color, with a few restricted 
dark markings above, and almost wholly white below! 
As we approach the humid regions of the Pacific slope, we 
enter the range of the typical Dusky Horned Owl, well named 
saturatus, for the dampness of the atmosphere has permeated his 
plumage, giving it a dark sooty brown tone, wholly without yel- 
low or buff. 
Finally in the dry, arid waste of Lower California, lives the 
extreme southern type, the small Dwarf Horned Owl. 
Our Horned Owl of the east, perched quietly in a tree, seems the 
personification of gentleness and good nature. The sharp beak 
and talon are buried in the fluffy feathers and the half-shut eyes 
are softened. But as night approaches and the pangs of hunger 
are felt, a transformation takes place in the bird. After sundry 
stretches and yawns, his eyes open wide, shining with a fierce 
