160 NEW YORK ZOOLOGICAL SOCIETY. 



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. 



