160 NEW YORK “ZOOLOGICAL. SOCIEIM 
will recognize its owner, and allow him to take almost any 
familiarity with it. If occasionally given its freedom it will return 
to its human home. In Zoological Gardens, owls live and thrive 
for long periods of time, and sometimes nest and rear their young. 
It is not sufficient, however, to feed captive owls on a diet of 
raw meat and liver. To remain in perfect health, they occa- 
sionally require dead mice, sparrows, or pigeons, the fur, feathers, 
and bones serving to keep their digestive organs in good con- 
dition. If the regurgitative function is not exercised, the birds 
will not long survive. 
As regards snowy owls, special arrangements are necessary. 
They will not moult well or live long if compelled to endure 
the heat of our southern summers, but if confined in a large 
flying-cage in a cool, dark cellar, every feather will be moulted, 
and bones serving to keep their digestive organs in good con- 
in as perfect condition as if they had spent the preceding months 
on their native tundras of the Arctic Zone. 
PARALLELS AND RELATIONSHIPS. 
As we pass in review the larger mammals and birds we per- 
ceive two important groups of predatory creatures which, by 
stress of the struggle for food, have become adapted to a nocturnal 
life. Among mammals the Felidae or cats, and among birds the 
owls, both live by the chase and both are fitted for a more or less 
nocturnal existence. This similarity of life has brought about 
certain resemblances between the two unrelated groups. Cats 
have a stealthy, noiseless gait—owls fly silently; the eyes of cats 
are large and usually yellow—the same is true of owls; talons 
are developed to a high degree in both groups, and both cats and 
owls voice their emotions in deep, sonorous tones or in high- 
pitched weird screams. 
Another curious but wholly superficial likeness, is the resem- 
blance of the feather horns or ‘ears’ of many species of owls, to 
the alert ears of the cats and other Carnivores. These elongated 
feathers have, however, no connection with the real ears of the 
birds. 
If we compare owls with the diurnal birds of prey—hawks 
and eagles—we find many and much closer resemblances. But 
these two groups are by no means as closely related, structurally, 
as ornithologists have heretofore thought. Many of the resem- 
blances are merely parallelisms due to the identity of methods of 
hunting their prey, and are only beak and talon deep. 
