90 Birds of Colorado 



b^ Bill shorter ; culmen less than the middle toe and claw. 

 a* No frontal shield. 



a' Larger ; wing over 4 ; nostrils about the middle of 



the bill. Porzana, p. 95. 



b' Smaller ; wing under 3 ; nostrils nearer the base of 



the bUl. Creciscus, p. 96. 



b^ A frontal shield on the front part of the head. 



Gallinula, p. 97. 



b. Toes with a series of lateral marginal lobes ; a frontal shield 



present. Fulica, p, 97. 



Family GRUID^E. 



The Cranes are large birds with long legs and necks ; 

 the bill is long and generally exceeds the length of the 

 head ; part of the face is generally naked and often 

 wattled or papillose ; there are twelve tail-feathers and 

 eleven primaries, and the trachea or windpipe is generally 

 convoluted and packed away in a hollow space formed 

 between the walls of the keel of the sternum ; the legs 

 are long, the tarsi scutellate in front, the toes short 

 and webbed at the base ; the hallux very short and 

 elevated above the other toes. 



The Cranes are externally not unlike the Storks, with 

 which they were formerly often associated, but they 

 differ very essentially in internal structure. Externally 

 they may be distinguished by the grooving of the bill, 

 in which are situated the nostrils, and by the elevation 

 of the hallux above the toes. 



Genus GRUS. 



The characters of the family, to which may be added — plumage 

 white or grey in the adult, rusty in the young ; head more or less 

 bare of feathers and not crested. 



All the three North American species have been taken in Colorado. 



Key of the Species. 



A. Pltunage white, primaries black. G. americana, p. 91. 



B. Plumage slaty -grey. 



a. Larger ; wing 21 — 22. G. mexicana, p. 92. 



b. Smaller; wing 18 — 19. G. canadensis, p. 91. 



