FAMILY ARDEIDAE 79 



Bill and tarsi greenish slate ; white, with tips of primaries gray ; or, in some, 

 plumage variegated with white and gray. 



Immature little blue heron, Florida caerulea, p. 91 



9. Throat completely feathered 10 



Throat wholly bare, or feathered only in the central line 19 



10. Smaller, wing less than 185 mm 11 



Larger, wing more than 225 mm 13 



11. Coloration in general darker; decidedly larger, wing more than 150 mm. 



(genus Butorides) 12 



Coloration in general paler, more bufify ; decidedly smaller, wing 100 to 

 115 mm Least bittern, Ixobrychus exilis, p. 113 



12. Sides of head and neck reddish brown. 



Green heron, Butorides virescens, p. 83 

 Sides of head plain gray, or washed with light cinnamon brown. 



Striated heron, Butorides striatus, p. 86 



13. Coloration not predominantly light brown or buflfy brown 14 



Mainly light brown, buflf, and buffy brown. 



American bittern, Botaurus lentiginosus, p. 112 



14. Plumage particolored, with variegated pattern 15 



Plumage dark throughout ; grayish blue, with head and neck washed lightly 



with chestnut Adult little blue heron, Florida caertdea, p. 91 



15. Body form more robust, bill shorter, 75 mm. long or less 16 



Body form very slender, bill longer, 90 mm. or more; breast and abdomen 



white, foreneck slate-gray, or brownish red. 



Tricolored heron, Hydranassa tricolor ruficollis, p. 92 



16. Heavily streaked throughout 17 



Without prominent streaks 18 



17. Darker; bill more robust; under side of wing dark gray, with under wing 



coverts prominently streaked with white. 



Immature yellow-crowned night heron, Nyctanassa violacea, p. 100 

 Paler; bill more slender toward tip; under side of wing light gray, with 

 spotting on under wing coverts not prominent. 

 Immature black-crowned night heron, Nycticorax nycticorax hoactli, p. 99 



18. Sides of head and throat black ; breast gray. 



Adult yellow-crowned night heron, Nyctanassa violacea, p. 100 

 Sides of head gray ; throat and breast white. 



Adult black-crowned night heron, Nycticorax nycticorax hoactli, p. 99 



19. A line of feathers down center of throat, with an elongated bare space on 



either side 20 



Throat completely bare. 



Bare-throated tiger-bittern, Heterocnus mexicamis, p. 103 



20. Tarsus longer, 92 to 115 mm.; bill more slender, with culmen nearly straight 



toward tip : Adult, with head and neck cinnamon, banded with black : 

 Immature, cinnamon-buff, heavily banded with black; white of abdomen 

 of less amount .. Banded tiger-bittern, Tigrisoma lineatum lineatum, p. 106 

 Tarsus shorter, 81 to 91 mm. ; bill heavier, with culmen more curved toward 

 tip: Adult, with head and neck black, banded narrowly with cinnamon- 

 buff : Immature, like Tigrisoma I. lineatum, but more extensively white 

 on lower breast and abdomen. 



Salmon's tiger-bittern, Tigrisoma sabnoni, p. 109 



