78 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



coverts. The female has the throat and foreneck whitish or ashy; 

 and in the immature the light-colored head is washed prominently 

 with rusty brown. In Fregata magnificens, common in Panama, 

 the male has a purplish sheen on the back and has no wing band ; 

 the female has the throat and foreneck blackish; and the imma- 

 ture has the head plain white. The two species are similar in size.] 



Order CICONIIFORMES 



Family ARDEIDAE: Herons; Garzas 



The numerous species of herons, worldwide in distribution, 

 agree in long legs and long necks, suitable for their type of life in 

 haunts along shores and in shallow waters. They show much di- 

 versity in size, from the small least bitterns to the tall great blue 

 and cocoi herons, and equally wide variation in color. Most of 

 them are able to maintain themselves in settled regions, now that 

 their plumage is no longer a commercial item. Only the tiger-bitterns 

 disappear as human settlement increases. 



KEY TO SPECIES OF ARDEIDAE 



1. Bill longer, 125 mm. or more 2 



Bill shorter, not more than 100 mm 4 



2. Larger birds, a meter or more in length, bill strong (genus Ardea) .... 3 

 Medium-sized birds, 750 mm. or less in length, bill very slender, about 150 



mm. long Agami heron, Agamia agami, p. 95 



3. Paler, whiter in general appearance ; tibia white or gray. 



Cocoi heron, Ardea cocoi, p. 82 

 Darker, decidedly grayer in general appearance; tibia chestnut or chestnut- 

 brown Great blue heron, Ardea herodias, p. 80 



4. Mainly plain white, white tinged with buff, or white variegated with 



gray 5 



Definitely darker in color, uniformly dark slate, or with plumage of varie- 

 gated pattern 9 



5. Bill yellow 6 



Bill not yellow 7 



6. Larger, length 850 mm. to a meter ; pure white. 



Common egret, Casmerodiiis albiis egretta, p. 88 



Smaller, length 460 to 560 mm., plain white, or with crown and breast buff 



(in breeding dress) Cattle egret, Bubulcus ibis ibis, p. 93 



7. Crown white, white variegated with gray, or slate gray, without elongfated 



plumes 8 



Crown black, with elongated white plumes. 



Capped heron, Philherodius pileatus, p. 97 



8. Bill and tarsi black, toes yellow ; plumage entirely white. 



Snowy egret, Egretta thtila thula, p. 89 



