308 ZOOLOGY. 



longer tail, and more active and shy habits ; its breeding phicc is not well 

 ascertained, notwithstanding that it is a common species. 



One genus only, Micrastur^ Gray, is exclusively confined to tropical Ame- 

 rica, t'Ao species of Avhich, M. hrachyptenis and gucr'Ula, are found as far 

 north as Mexico. They differ from the other AcclpitrincB in having stouter 

 a.nd much stronger bills, and are otherwise more robust. The latter species, 

 M. guerilla, was discovered in Mexico by a young naturalist, who was at- 

 tached to the American army, under General Scott, during the late war. 



There is also one African genus, Microtdsus, Gray, of whicli the M. gobar 

 is the best known species, resembling, however, in most respects its Eui-opean 

 and American relatives. 



Sub-fam. 7. Circiufc, or Harriers. Bill weak, high at base, compressed, 

 greatly curved to the tip, margins slightly festooned in the middle, cere large, 

 gape wide, ears large, and surrounded by a ruff of thickly curved feathers, 

 similar to those of the owls. Wings long and pointed ; tail long, broad, and 

 generally rounded. Tarsi long, slender, smooth ; toes short ; claws moderate, 

 very acute. Size greatly varied. 



In this, the last of the seven sub-families which constitute the great fimily 

 of the Falconidcc, we find characters begin to show themselves indicating a 

 relationship to another famil}^, the Strigidoi, or owls, which we are approach- 

 ing, but still retaining the essential and unmistakable characters of their OAvn 

 family. 



The typical genus Circus, well represented by the hen harrier of Europe 

 (C cyaeni(s), has a dccidedl}'' owl-like ruff of small recurved feathers around 

 the face, and the eyes of all the species have a less lateral aspect than 

 those of any other falcons. The species just mentioned is common 

 throughout Europe ; its plumage varies very greatly during its progress to 

 maturity, a circumstance which has caused it to be mistaken by the earlier 

 naturalists, and the same bird to be described as several different species. 

 The fully ailult bird is light sky blue with the under parts white, and is a 

 handsome and showy bird. It is very shy and harmless in its habits, living 

 almost entirely upon reptiles. There arc several other European species, 

 of which the moor buzzard (C. aruginosus), is, perhaps, the most remark- 

 able. Its geographical range extends into Africa ; it is said to frequent 

 the vicinity of swamps and rivers, and to feed upon small aquatic birds 

 and the eggs of larger species, and upon snakes, frogs, and other small 

 animals. 



One species only of this sub-family inhabits North America, which is the 

 marsh hawk (C idiginosus), one of the most common species. It is an 

 exceedingly graceful bird when flying, and may often be seen about 

 marshes and meadows, constantly on the wing near the surface of the 

 earth, in search of small quadrupeds and reptiles. The young bird has its 

 plumage of dark reddish colors, Avith a very conspicuous snow-white rump ; 

 while the adult, which is more rarely seen, is of nearly the same light blue 

 color as its European representative. It appears to be particularly fond of 

 frogs, upon finding one of which it generally secures him with its exceed- 

 ingly short claws without difficulty, and if undisturbed devours him on the 

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