312 Mr. 0. Salvin on the Birds of Nicaragua. 



Mr. Bellas collection. A glance at the riches of the surrounding 

 countries, Guatemala with its 600 species and upwards, and Costa 

 Rica with considerably over 500, shows that we cannot con- 

 sider our knowledge of the bird-fauna of Nicaragua at present 

 anything more than fragmentary ; for, Nicaragua being clothed 

 with rich tropical vegetation, interspersed with open plains, 

 and also possessing a volcanic chain of mountains of no in- 

 considerable altitude, we cannot but anticipate that future ex- 

 plorations will reveal a bird-fauna as rich in specific forms as that 

 we know to exist in the surrounding regions. 



Though our knowledge can only be considered imperfect, 

 enough is before us to enable us to form a tolerably accurate 

 opinion as to which of the two subprovinces of the Central- 

 American fauna the eastern or Chontales side of Nicaragua be- 

 longs. These subprovinces are indicated in my two papers on 

 Veraguan Birds, published in the ' Proceedings of the Zoological 

 Society' for 1867 and 1870. I there endeavoured to show that 

 the district lying on the South-American side of the lake of Ni- 

 caragua, and that included in Southern Mexico and Guatemala^ 

 formed two great faunistic divisions of Central America. The 

 birds noticed in the present paper are from no great distance 

 from the boundary between the two ; but they show pretty con- 

 clusively that the depression of the Isthmus, represented by the 

 great Nicaraguan lakes and their outfall, the Rio San Juan, does 

 not form the actual bo undary between them, but that thisboundary 

 must be sought further north-westwards, towards Honduras. 

 What I suspect to be the case, though I cannot as yet bring 

 evidence to prove it, is that the forests of Chontales spread un- 

 interruptedly into Costa Rica, but that towards the north and 

 north-west a decided break occurs and that this break determines 

 the range of the prevalent Costa-Rican and Guatemalan forest- 

 forms. 



There are difficulties connected with the supposition that the 

 Lake of Nicaragua once formed the bed of an interoceanic chan- 

 nel, when viewed with reference to the very peculiar aspect of the 

 freshwater fish of the lake ; but this extension of the southern 

 bird-fauna is by no means incompatible with the theory of the 

 former existence of such a channel, if then (as would appear 



