THE DIURNAL BIRDS OF PREY HAWKS, EAGLES AND 



VULTURES 



(Pantiles Buteonidae Falconidae, Pandionldae and Cathartidae) 



BY A. A. ALLEN, PH.D. 



ASSISTANT PROFESSOR OF ORNITHOLOGY, CORNELL UNIVERSITY 



NATURE does not intend her children to lead easy 

 lives. As soon as life becomes easy, progress 

 ceases and decay sets in. There must be constant 

 struggle and competition and only the best and strongest 

 must live to perpetuate their kind. She has little time 

 to waste on the weak or the lazy; the sooner they are 

 out of the way, the better for the rest. So Nature has 

 provided obstacles which every organism must surmount 

 to reach maturity, <ind enemies to its adult life which re- 

 quire constant alertness and 

 courage to escape. She 

 provides every organism 

 with a capacity for repro- 

 duction commensurate with 

 number of obstacles or 

 enemies with which it must 

 cope, so that, though many 

 may fall by the wayside, 

 the most virile and progres- 

 sive individuals will be 

 left to continue the race. 

 Wherever Nature exists un- 

 modified by man, we find a 

 balance of these two great 

 forces, that of reproduction 

 and that of destruction. 



A single protozoon in a 

 jar of water will, in a few 

 days, cause the entire jar 

 to appear milky with its 

 thousands of offspring in 

 order that at least one of its 

 children may reach maturi- 

 ty and be carried to some 

 other suitable environment. 

 A soft-bodied, helpless 

 plant louse reproduces at 

 the rate of over ten sextillion a year for the same reason, 

 and the oak tree showers its acorns on the ground every 

 season, that at least one may be carried to fertile ground, 

 surmount the obstacles of browsing animals and defoliat- 

 ing insects and at last bear acorns of its own. The proto- 

 zoon, or the plant louse or the oak tree that finally reaches 

 maturity is the pick of thousands and has all the vitality 

 of its parents and usually a little more. For it is thus 

 that nature progresses and thus that the most complicated 

 organisms and even man have evolved from the lower 

 and more simple. 



And so we find whole groups of organisms intended 

 by nature to cull out the weaker individuals of other 

 species and thus assist the process of evolution. Among 

 animals it is the carnivores, the tigers, the wolves, the 



OUR NATIONAL BIRD 



The liberty bird that permits no liberties. All hawks can be distinguished 

 by their sharply hooked bills and the absence of the facial disk which 

 characterizes the owls. 



bears, the weasels and their kin. Among birds it is the 

 birds of prey, the hawks and the owls, that perform this 

 necessary function of insuring the strength of the differ- 

 ent species of birds. 



Of course man does not feel the need of this method of 

 maintaining the strength of his domestic fowls and rues 

 the slightest pillaging of his poultry yard or game 

 covers. Fortunately there are few species that indulge 

 freely in this thievery and the majority more than make 



up for it in their destruc- 

 tion of harmful rodents, 

 for the food of hawks is 

 composed even more of 

 rodents than of birds. 



There are nearly 500 dif- 

 ferent kinds of hawks, 

 found in all parts of the 

 world. Many species re- 

 semble each other very 

 closely, others have diverg- 

 ed widely, but all can be 

 recognized by their short, 

 hooked bills, their strong 

 talons, and the absence of 

 the facial disk which char- 

 acterizes the owls. Parrots, 

 which are somewhat hawk- 

 like in appearance, have 

 very thick bills and have 

 two toes directed forward 

 and two backward instead 

 of three in front and one 

 behind. 



Hawks vary in size from 

 the gigantic condor and the 

 California vulture, the 

 former measuring over 12 

 feet from tip to tip of the wings, to the pigmy falcons 

 of India, which are scarcely larger than sparrows. 

 The females are usually larger than the males, frequent- 

 ly exceeding them by several inches in length. Thus the 

 male Cooper's hawk measures but a little over fifteen 

 inches in length while the female averages 19 inches. 

 Most species are inconspicuously marked with brown 

 and gray but some have quite striking patterns of blue 

 and reddish brown. With some species, like the marsh 

 hawk, the male and female are different, but usually the 

 adults are colored alike and the immature are different. 

 The adults tend to become very gray above and barred 

 below while the immatures are brownish above and 

 streaked rather than barred on the breast. The color 

 patterns of many species are so similar that it is much 



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