Migrations of North American Birds. 265 



the Rio Grande and Colorado far into the United States. It is 

 the species of this subdivision that, with those pecuUar to Cape 

 St. Lucas, characterize the summer fauna of the latter region. 

 In winter, both there and along the Mexican boundary line, 

 these species are mingled with others coming from the more 

 northern portions of the middle province. 



In addition, however, to possessing certain species of the 

 boundary-line fauna. Cape St. Lucas has other peculiarities 

 which entitle it to especial consideration*. 



It forms a distinct subdivision of the boundary subprovince 

 even more peculiar in its relations than Florida, where the 

 characteristic species (excepting the Florida Jay) are stragglers 

 of the West Indian type from the Bahamas, while, as shown by 

 the indefatigable researches of Mr. Xantusf, there are at least 

 twenty species found at Cape St. Lucas not known elsewhere. 



Very few of the birds of the coast of California, or of the 

 western province, winter at Cape St. Lucas, the species being 

 almost entirely those of the middle province. The new and 

 peculiar species in all cases belong to genera of the middle pro- 

 vince, especially of its boundary subdivision ; and no genera are 

 peculiar to it. Furthermore, in no instance do we find species 

 of the tier7'a caliente of Mexico not belonging to the United 

 States, nor of any Mexican genera that do not possess repre- 

 sentatives in the United States. The difference between the 

 species of birds of Cape St. Lucas and of Mazatlan is very great, 

 although separated only by the breadth of the Gulf of California. 



From all these considerations we are legitimately entitled to 

 claim Lower California, or at least its southern extremity, as 

 belonging to temperate North America, even more positively 

 than Florida itself. 



Peculiarities in regard to the size of Cape St. Lucas birds 

 will hereafter be referred to. 



There is of course an Arctic province which melts gradually 

 into those great provinces mentioned, and along the moun- 

 tainous ranges extending far southward, in fact almost into 

 Mexico, as shown by the occurrence in summer at Cantonment 

 * See Baird, Pr. Acad. Nat. Sci., Nov. Sth, 1859. 

 t See Xantus, Pr. A. N. S., Nov. 1859. 



