336 



NOUTII AMERICAN BIRDS. 



of tlie crop. Although not truly gregarious, they assemble in multitudes 

 where food is plenty, and some species breed in communities. When gorged, 

 they appear heavy and indisposed to exertion, usually passing the period of 

 digestion motionless, in a listless attitude, with their wings half spread. But 

 they spend most of the time on wing, circling high in tlie air ; their flight is 

 easy and graceful in the extreme, and capable of being indefinitely pro- 

 tracted. On the ground, they habitually walk instead of progressing by 

 leai)s. Possessing no \ocal apparatus, the Vultures are almost mute, emitting 

 only a weak hissing sound." (CouES.) 



The Cathartidte all belong to the tropical and warm temperate portions of 

 tlie continent, only one species {Rhinogryphus aura) e.xtending its range as 

 far as the border of the colder regions. The famous Condor {Sarcorhamphus 

 gryplms) of the Andes and the equally large California species {Pscudognj- 

 p)lms cnliforniuaus) are among the largest birds of flight m the world, being 



exceeded in size by none, and rivalled 

 but by one or two of the Vultures 

 of the Eastern Hemisphere. 



The following diagnoses based upon 

 the external structure are suflficieut 

 to cliaracterize the very well-marked 

 genera and subgenera of this family. 

 The distinctive osteological characters 

 which accompany these external fea- 

 tures afford still more decided differ- 

 ences, and are illustrated by the fig- 

 ures. 



S. gryphuSj (^, Chile. ^ nat. size. 



S. papa, 9 , Mazatlan. >^ nat. 



Genera and Subgenera. 



A. Crop naked. Male with a flu.shy crest, or lobe, attached to the top of the 

 cere. Bill very robust and strong, its outlines very convex; cere much shorter 

 than the head. 



1. Sarcorhamphus. Entire neck bare; nasal cavity entirely open ; pos- 

 terior claw very thick and stroncly curved. Tail even. 



Sexes different, the female lacking any fleshy caruncles, or appendages, 

 on the head and neck. Frontal lobe, or fleshy crest of male, extending 

 from the anterior border of the cere to the middle of the crown ; throat 

 with a median wattle, or " dewlap " ; side of the neck with a somewhat 

 convoluted or twisted caruncle, extending from the side of the occiput 



