82 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. IX. 



* GROUP 4. Wing, n to 15 inches long. 



Bill, stout; top of the head, black; back, dark green; culmen, 

 about as long as tarsus (adult). 



Nycticorax nycticorax nasvius. 

 Black-crowned Night Heron. 



See No. 88. 



Bill, stout; top of head, white or whitish; back, not green; cul- 

 men, much shorter than tarsus (adult). 



Nyctanassa violacea. 

 Yellow-crowned Night Heron. 

 See No. 89. 



Bill, stout; general plumage, mottled and streaked brown and 

 white; outer edge of primaries, reddish brown ; culmen, about as long 

 as tarsus (immature ) . Nycticorax nycticorax navius. 



Black-crowned Night Heron. 



See No. 88. 



Bill, stout; general plumage, mottled and streaked grayish brown 

 and white; primaries, slaty brown ; culmen, much shorter than tarsus 

 (immature ) . Nyctanassa violacea . 



Yellow-crowned Night Heron. 



See No. 80. 



American Egret. 



General plumage, white; bill, yellow; legs, black. 



Herodias egretta. 

 American Egret. 



See No. 83. 



* For directions for measurement, see page 21. 



