AVES PALCONIDyG. 649 



GENERAL DESCRIPTION. 

 Size. Adult male. 

 Total length, about 20.00 inches. 

 Wing, 15.7 inches. 

 Culmen, i.o inch. 

 Tail, 8.7 inches. 

 Tarsus, 2.8 inches. 



There is a very considerable variation in size in different adult male 

 birds ; this one given is rather large. 



Fio. 330. 



Butto twainsoia. Adult male. Natural size. 



Color. Adult male. 



Head: Forehead white; crown, sides of head and face deep greyish 

 brown, the feathers cottony at their bases. 



Neck: Chin and throat white, the color terminating abruptly on the 

 chest and forming a white patch ; rest of the neck like the head, but a 

 little lighter on the nape. 



Back : Interscapular region, back, rump and upper tail-coverts uniform 

 greyish brown. 



Tail : Dull greyish brown, often inclining to hoary, and crossed by nine 

 or ten darker bars, which become obsolete at the base of the feathers ; the 



