BIRDS OF KORTH AND MIDDLE AMERICA. 279 



resembling that made by blowing one's breath into the mouth of a 

 bottle, but nearly as loud as the bellowing of a bull. In others the 

 voice is plaintive or even mournful. 



Pigeons are found throughout the temperate and tropical portions 

 of the world, but are most numerous in the Eastern Hemisphere, espe- 

 cially in the islands of the Indo-Malayan and Australian regions, 

 where the most beautifully colored species occur, many of them 

 being among the most beautiful of birds. More than five hundred 

 and fifty species and subspecies, belonging to ninety-one genera, are 

 known, of which only about one hundred species and subspecies and 

 twenty-five genera occur in America. 



The nearest hving relatives of the Pigeons are the Sand Grouse 

 (Family Pteroclidae) , constituting the order or suborder Pteroclo- 

 formes or Pterocletes, which are very nearly intermediate in struc- 

 tural characters between the Columbiformes and Galliformes. At 

 the same time the Pigeons show relationship to the Charadriiformes, 

 and even, though far more remotely, to the Owls '(Striges) and 

 American Vultures (Sarcoramphi) . 



KEY TO THE AMERICAN GENERA OF COLUMB^.« 



a. Wing relatively longer and more pointed, the longest primaries exceeding distal 

 secondaries by more than one-tliird the length of wing; tarsus less than one- 

 sixth as long as wing. (Secondaries diastataxic=aquintocubital.)^ 

 b. Middle toe (without daw) at least nine-tenths as long aa tarsus, the latter with 

 upper portion more or less feathered in front. 



c. Tail less than four-fifths as long as wing (sometimes only half as long), 



rounded or truncated, the rectrices broad throughout, broadly rounded at tip. 



(Columbx.) 



d. Tarsus as long as or longer than middle toe without claw; secondaries with 



exposed portion shorter than exposed portion of greater coverts. 



e. First and second primaries (from outside) longest, the first much longer 



than third, and, with second, subacute at tip and with inner webs not 



excised; foreneck with plumage metallic Lithoenas (extralimital).c 



ee. Second and third primaries (from outside) longest, the first not longer 



than fourth, the two outermost primaries rounded or obtuse at tip, 



their inner webs excised beyond middle portion; foreneck with plumage 



not metallic. 



/. Tarsus longer than middle toe without claw, only the extreme upper 



portion feathered in front; toes more slender, with smoother scutella 



and less expanded as well as less strongly papillose or spiculate soles; 



a Including, for comparison, a few related European genera. 



b In Leptotila and "Geotrygon" (=Geotrygon-{-Oreopeleia) the secondaries arediasta- 

 taxic (aquintocubital). See Miller, Bull. Am. Mus. N. H., xxxiv (art. vi, March 19, 

 1915, 130). Osculatia, which is closely related to Oreopeleia, has not been examined 

 with reference to this character. 



c Lithoenas Reichenbach, Av. Syst. Nat., 1852, p. xxv; type, Columba livia 

 Linnaeus. — Rupicola (not of Brisson, 1760) Bogdanow, Trudy St.-Petersb. Obshch., 

 xii, 1881, 99 (subgenus); type, Columba livia Linnaeus. (Palaearctic.) 



