Part 40

Tinnunculus sparverius.]

The subgenus Tinnunculus is one which is well characterized by peculiarities of manners and habits as well as by features of structure. The species are the most arboreal of the Falcons, and their curious habit of poising in a fixed position as they hover over some object of food which they are watching is probably peculiar to them, and has been remarked of the Old World as well as of the American species. In their structure they are the most aberrant members of the subfamily belonging to the Northern Hemisphere and in their weak bill and feet, lengthened tarsi, obtusely tipped quills, more rounded wings, and more lengthened tail, exhibit a decided step toward Hieracidea, an Australian genus which is almost exactly intermediate in all the characters of its external structure between the true Falcons and the South American genus Milvago, of the Polyborine group.

The subgenus is most largely developed in the Old World, where are found about a dozen nominal species, of which perhaps one half must be reduced to the rank of geographical races. America possesses three species, two of which are restricted to the West India islands, while the other extends over the entire continent.

There is no reason whatever for separating the American species from those of the Old World, and the subgenus Pœcilornis, established upon these by Kaup, is not tenable.

Since the publication of my first paper upon the American forms of Tinnunculus, a large amount of additional material has fallen under my observation; the total number of examples critically examined and compared together amounting to over three hundred and fifty skins of which I have kept a record, besides many others which have come casually to my notice. This abundant material merely confirms the views I first expressed, in the paper alluded to, regarding the number and definition of the forms; their comparative relation to each other being the only respect in which I have reason to modify my arrangement.

In my first paper on the American Tinnunculi, three distinct species were recognized; one (sparverius) belonging to the whole of Continental America and the Lesser Antilles, one (leucophrys, Ridgway) to Cuba and Hayti, and one (sparveroides, Vig.) peculiar to Cuba. The first is one modified in different climatic regions into several geographical races, as follows: Var. sparverius, L., North and Middle America, exclusive of the gulf and Caribbean coast region; var. isabellinus, Swains., the eastern coast region of Tropical America, from Guiana to Florida; var. dominicensis, Gmel. (Lesser Antilles); var. australis, Ridgw. (South America in general); and var. cinnamominus, Swains. (Chile and Western Brazil). That each of these races is well characterized, the evidence of a series abundantly sufficient to determine this point enables me to assert without reserve; for I find in each instance that the characters diagnosed in my synopsis hold good as well with a large series as with a few specimens.

The following synopsis, essentially the same as that before published, may, to most persons, explain satisfactorily my reasons for recognizing so many races of T. sparverius,—a proceeding which, I am sorry to say, does not meet with favor with all ornithologists. Though there are at the present time three well-characterized or permanently differentiated species of Tinnunculus on the American continent, yet it is, to my mind, certain that these have all descended from a common ancestral stock, for evidence in proof of this is found in many specimens which I consider at least strongly “suggestive” of this fact; some specimens of var. isabellinus from Florida having blue feathers interspersed over the rump, thereby showing an approximation toward the uniformly blue upper surface of the adult male of T. sparveroides of the neighboring island of Cuba; while in the latter bird the embryonic plumage of the male is very similar to the permanent condition of the male of sparverius.

Synopsis of the American Species.

=A.= Back always entirely rufous (with or without black bars.) Lower parts white, or only tinged with ochraceous; front and auriculars distinctly whitish.

a. Inner webs of primaries barred entirely across, with white and dusky; “mustache” across the cheeks conspicuous; no conspicuous superciliary stripe of white.

1. =T. sparverius.= Crown bluish, with or without a patch of rufous. ♂. Wings and upper part of head slaty, or ashy-blue; scapulars, back, rump, and tail reddish-rufous; primaries, basal half of the secondaries, and a broad subterminal zone across the tail, black. ♀. The bluish, except that of the head, replaced by rufous, which is everywhere barred with blackish, and of a less reddish cast. Hab. Entire continent of America, also Lesser Antilles, north to St. Thomas.

b. Inner webs of primaries white, merely serrated along the shaft with dusky; “mustache” obsolete or wanting; a conspicuous superciliary stripe of white.

2. =T. leucophrys.= Similar to sparverius, except as characterized above. Hab. Cuba and Hayti.

=B.= Back rufous only in the ♀. Lower parts deep ferruginous-rufous; front and auriculars dusky.

3. =T. sparveroides.= ♂. Above, except the tail, entirely dark plumbeous, with a blackish nuchal collar; primaries and edges and subterminal portion of tail-feathers, black. Beneath deep rufous (like the back of sparverius and leucophrys), with a wash of plumbeous across the jugulum; throat grayish-white. Inner webs of primaries slaty, with transverse cloudings of darker. ♀. Differing from that of the above species in dark rufous lower parts and dusky, mottled inner webs of primaries. Second and third quills longest; first shorter than or equal to fourth. Hab. Cuba (only?).

The distinguishing characters of F. sparverius having been given in the foregoing synopsis, I will here consider this species in regard to the modifications it experiences in the different regions of its geographical distribution.

The whole of continental America, from the Arctic regions to almost the extreme of South America, and from ocean to ocean, is inhabited, so far as known, by but this one species of Tinnunculus. But in different portions of this vast extent of territory the species experiences modifications under the influence of certain climatic and other local conditions, which are here characterized as geographical races; these, let me say, present their distinctive characteristics with great uniformity and constancy, although the differences from the typical or restricted sparverius are not very great. The F. sparverius as restricted, or what is more properly termed var. sparverius, inhabits the whole of North and Middle America (both coasts included, except those of the Gulf of Mexico and Caribbean Sea), south to the Isthmus of Panama. Throughout this whole region it is everywhere nearly the same bird. This variety appears to represent the species in its greatest purity, being a sort of central form from which the others radiate. The most typical examples of the var. sparverius are the specimens in the large series from the elevated regions or plateau of Mexico and Guatemala. In these the rufous of the crown is most extended (in none is it at all restricted), and the ashy portions are of the finest or bluest and lightest tint.

All specimens, of quite a large series, from the peninsula of Lower California, are considerably smaller than any others, the smallest (1,693 ♂ ad. San José; J. Xantus) measuring, wing, 6.50; tail, 4.20, and tarsus, 1.30; the dwarfed size of these, however, is their only distinguishing feature. Two specimens (50,199, ♂, Cape Florida, and 10,345, ♀, Indian Key) from Florida differ from others in the unusual development of the bill, which toward the end is more suddenly curved, and the point considerably lengthened; these specimens have, also, only a tinge of rufous on the crown, thus showing a proximity to the var. isabellinus. The large bill, however, is no more than would be looked for in specimens from that region.

Along the Gulf border of the United States, and the Caribbean and North Atlantic coasts of South America (probably the whole Atlantic coast of tropical and subtropical America), the true sparverius is changed into what Swainson has called “Falco isabellinus,” which differs from the former only in having the cinereous of the crown and wings considerably darker (as well as less bluish), approaching plumbeous; 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 dominicensis of Gmelin (based upon description by Brisson), which inhabits the Lesser Antilles, from Trinidad northward to Porto Rico. Although I consider this (var. dominicensis) as a modified form of the var. isabellinus, yet it is the one of all the varieties referrible to sparverius which deviates most widely from the typical or original style. The characters 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 than in any other American member of the genus. A style of considerable uniformity spreads over the whole of South America, including both coasts, from Bogota to the Parana, excepting the northeastern coast region, before mentioned as inhabited by the var. isabellinus. It differs from all the other 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. sparverius, 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. (Tinnunculus) gracilis of Lesson being a different species, and the name as applied to it of prior date, I have bestowed 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 immaculate rufous, etc. The grayish of the head is much darker and more 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 crown 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. Neither does the exact number of spots on the lateral tail-feather prove sufficiently constant to serve as a character in which the least reliance can be placed, though Swainson attaches considerable value to it. I have found that, besides varying almost with the individual, in some specimens the feathers of opposite sides did not correspond.

About two hundred and fifty specimens form the basis of the following synopsis.

=A.= Tail tipped with white; outer tail-feathers (one or more) variegated.

a. ♂. Head above, and wings, fine bluish-ash; usually one tail-feather only (the outer) variegated.

1. Vertex with a conspicuous patch of rufous. ♂. Black zone of the tail 1.00 in width; breast strongly tinged with ochraceous; spots of black on the breast or sides circular. ♀. Above fulvous-rufous, the whole breast and sides with longitudinal dashes of a lighter tint of the same. Hab. Continent of North America north of Panama (except Caribbean and Gulf coast) …

var. sparverius.

2. Vertex with only a trace of rufous, or none at all. ♂. Black zone of tail only .60 in width; breast nearly pure white; spots of black usually only on the sides, elliptical. ♀. Above vinaceous-rufous; longitudinal markings beneath deeper brown. Hab. Continent of South America (except North Atlantic and Caribbean coast) …