I^O Allen, Origin and Distribution of N. A. Birds. [ April 



As already noted, the extreme southern portions of North 

 America belong to the American Tropical Realm, which consists 

 of tropical America at large. It thus includes not only a large 

 part of South America, Central America and the West Indies, 

 but the lowlands of Mexico, including the low eastern coast 

 region to some distance north of the mouth of the Rio Grande, 

 and the low western coast to some distance north of Mazatlan. 

 To the Tropical Realm belong also the extreme southern portion 

 of the peninsula of Lower California, and the extreme southern 

 portion of the peninsula of Florida. There are thus three small 

 portions of 'North America,' as defined in the A. O. U. Check- 

 List, which belong with the Tropical rather than to the North 

 Temperate Realm. 1 



The fauna of neither of the tropical areas within the United 

 States is typically tropical, but the infusion of tropical elements 

 is so great as to render them tropical rather than temperate. 

 They have also little in common with each other, as would be 

 naturally anticipated from their wide geographical separation 

 through the interposition of the Gulf of Mexico, thus preventing 

 a tropical land connection. Consequently the Floridian area, or 

 the Floridian Fauna, as it has long been technically known, 2 

 belongs to the Antillean Region of the American Tropical, while 

 the Texan area is an outlying arm of the Central American 

 Region of the American Tropical. The tropical portion of 

 Lower California also belongs to the Central American Region. 



The Floridian Fauna has recently been treated in much detail 

 by Dr. Merriam, 8 and hence need not be considered at length 

 here. The following birds, however, may be mentioned as 

 among those distinctively characteristic of this limited area, 

 though having generally a very extended range into tropical 

 America. 



1 See maps, plates III and IV, where the uncolored portions to the south of the 

 colored areas belong to the Tropical Realm. The uncolored portion at the top of 

 plate III may be taken as representing that portion of the continent belonging to the 

 Arctic. 



2 C/". Bull. Mus. Comp. Zool., 11,1871^.391. — The general provisional northern 

 limit here given — "near the latitude of Lake George"— proves to have been carried a 

 little too far north, its limits as now recognized being Cape Malabar on the east coast 

 and Tampa Bay on the west coast. (Cf. Merriam, Proc. Biol. Soc. Washington, VII, 

 1892, p. 33.) 



■* C/ 7 Merriam, Proc. Biol. Soc. Washington, VII, 1892, pp. 52-54. 



