FALCOXID-E — THE FALCONS. 165 



Atlantic coasts of South America (probably the whole Atlantic coast of 

 tropical and subtropical America), the true sparvcrius is changed into what 

 Swainson has called " Falco isaheUinus," which difi'ers from the former only 

 in having the cinereous of tlie crown and wings considerably darken- (as well 

 as less bluish), apiiroacliing ])lumbeous ; the rufous of the crown is totally 

 absent, or only present in faint touches ; the lower parts are of a deeper 

 ochraceous, and the black spots on the breast and sides sparse. 



Allied to the last in tints of coloration, and apparently a direct offshoot 

 from it, is the dominiccasis of Gmelin (based upon description by Brisson), 

 whi(!h inhabits the Lesser Antilles, from Trinidad northward to Porto Eico. 

 Althougli I consider this (var. dominiccHsis) as a modihed f(jrm of the var. 

 isabellinus, yet it is tlie one of all the varieties referrible to sparveTius 

 which deviates most widely from the tyjiical or original style. The charac- 

 ters of this are, tints those of var. isabellinus, but, in addition, the tail has 

 numerous more or less complete black bands, while those of the back and 

 scapulars are very broad and numerous ; also, the crown has a decided rufous 

 patch ; the bill, too, is larger tlian in any other American member of the 

 genus. A style of considerable imiformity spreads over the whole of South 

 America, including both coasts, from Bogota to the Parana, excepting the 

 northeastern coast region, before mentioned as inhabited bv the var. isahcl- 

 limi^. It differs from all the otlier styles, except the cinnamominus of Chile, 

 in having the lower parts continuously dull white, any ochraceous tinge 

 being scarcely perceptible ; there is seldom a trace of rufous on the crown, 

 which has the light bluish tint seen in var. sparvcrius, and the black zone 

 of the tail is scarcely more than half as wide as in the northern races. In 

 size, also, it somewhat exceeds the others. Swainson named this " Falco 

 gracilis " ; but the F. (Tinmtncuhis) gracilis of Lesson being a different spe- 

 cies, and the name as applied to it of prior date, I have bestov\'ed upon the 

 present bird the name var. australis. 



In Chile and Brazil (Western ?) we find a form resembling the last in some 

 respects, but differing in points of almost specific value. It differs from all 

 the other American members of the genus in having the tail continuously 

 rufous to the extreme tip, the black zone being considerably narrower than 

 the terminal rufous, the lateral tail-feather inmiaculate rufous, etc. The 

 grayish of the head is much darker and inoi'e slaty than in the var. australis. 

 This is, without doubt, the Falco cinnamominus of Swainson, the specimens 

 in the collection corresponding exactly with the description by that author. 



The rufous patch on the ci'own must not be too much considered, as it is 

 of all characters perhaps the most treacherous, though its presence or 

 absence is in a measure characteristic of the several varieties. Xeither does 

 the exact number of spots on the lateral tail-feather prove sufficiently con- 

 stant to serve as a character in which tlie least reliance can be ]ilaced, 

 though Swainson attaches considerable value to it. T ha\'e found tliat, 

 besides varying almost witli the inilividual, in some specimens the feather.'j 

 of opposite sides did not correspond. 



