Argentine Ornithology.
Volume I.
by P. L. Sclater and W. H. Hudson.
INTRODUCTION.
As regards its Bird-life the Neotropical Region, which, according to the arrangement usually adopted, consists of America south of the Isthmus of Tehuantepec together with the West Indies[1], may be most conveniently divided into six Subregions. These are:--
[1] _Cf._ Sclater, Journ. Linn. Soc., Zool. ii. p. 143 (1857).
1. The _Transpanamic Subregion_, embracing the great Central-American Isthmus from Tehuantepec down to Panama.
2. The _Antillean Subregion_, containing the West-India Islands.
3. The _Colombian Subregion_, containing the South-American littoral and the adjacent Andean ranges in Venezuela, Colombia, Ecuador, Peru, and Bolivia.
4. The _Amazonian Subregion_, containing Guiana and the valleys of the Orinoco and Amazons and their confluents.
5. The _Brazilian Subregion_, containing the great wooded and campos districts of Southern Brazil and Paraguay.
6. The _Patagonian Subregion_, consisting of Antarctic America up to the Brazilian wood-districts and the highlands of Bolivia on the eastern side of the Andes, and apparently extending as far as the Gulf of Guayaquil on the west.
It is, of course, impossible to draw a precise line between these six Subregions, and any boundaries a.s.signed to them can only be regarded as approximative; but it is obvious that nearly, if not quite, the whole of the Argentine Republic, the Avifauna of which we are now considering, comes within the limits of the Patagonian Subregion. It is possible that the birds of the Territory of Misiones and of some parts of Northern Corrientes may be more nearly akin to those of Brazil, but we may say generally that the Argentine Republic belongs to the Patagonian Subregion.
As shown in the succeeding pages, the number of species of Birds as yet ascertained to be found within the Argentine Republic[2] is about 430.
We will now take the leading groups of the Neotropical Ornis, one after another, and consider the _role_ they play in the Argentine Avifauna, so as to get some general ideas as to its peculiarities.
[2] We have not included within the scope of the present work the territory of Santa Cruz and Tierra del Fuego, which are politically part of the Argentine Republic, but only Northern Patagonia down to the Rio Negro.
The subjoined Table contains in the first column the number of Neotropical species a.s.signed to each of the 20 different Orders of Birds in the "Nomenclator Avium Neotropicalium." In the second column is given the corresponding number of Argentine species of each order according to the present work. The total number of Neotropical species will be seen to be about eight times as many as those of the Argentine Avifauna; so that where this average is exceeded in the individual orders the particular group may be considered to be over-represented, and where it is not reached to be under-represented in the Argentine Avifauna. This is of course a very rough-and-ready mode of calculation, because it a.s.sumes that every species has an equal area of distribution, which is not ordinarily the case; but it will serve to give us some general ideas on the subject. We will now proceed to consider the princ.i.p.al groups one after another, and to point out their comparative importance in the Argentine Avifauna.
The known Argentine Pa.s.seres, according to the present work, are 229 in number; those of the Neotropical Region, according to the "Nomenclator,"
are 1976; so that the species of Argentine Pa.s.seres, according to the ratio which we have adopted, would be very little short of the average numbers. If, however, we divide the Pa.s.seres up into the three suborders of Oscines, Oligomyodae, and Tracheophonae, we shall find that the Oligomyodae are rather in excess of the estimated average, while the species of the two other groups are deficient. This arises mainly from the large number of Tyrannidae belonging to the Argentine Ornis. Not less than 63 species of this group have been already discovered within its limits. Besides Tyrants, other prevailing families of Pa.s.seres in the Argentine Avifauna are the Finches (Fringillidae) and the Wood-hewers (Dendrocolaptidae), both of which have 46 representatives in the Argentine Republic. Both these families are, however, well represented all over the Neotropical Region. But the Tapacolas (Pteroptochidae) and the Plant-cutters (Phytotomidae) are both of them families specially characteristic of the Patagonian Avifauna, and both of them are represented in the Argentine Republic. One other Pa.s.serine form is also worthy of special mention. The Dippers (Cinclidae) are essentially an Arctic group diffused all over the Palaearctic and the Arctic Regions. It is singular, however, that this form should reoccur at higher elevations in the Neotropical Region. A _Cinclus_ is found in the mountains of Colombia, another in the Andes of Peru, and a third has lately been discovered in the northern sierras of the Argentine Republic. As regards Pa.s.serine birds, therefore, which great order makes up more than one half of the Argentine Ornis, we may say that Finches, Tyrants, and Wood-hewers are remarkable for their abundance, Plant-cutters and Tapacolas for peculiarity of type, and Dippers as an instance of the occurrence of an Arctic form in Antarctic lat.i.tudes.
As regards the second order, Macrochires, the Argentine Avifauna is notably deficient on account of the comparative scarcity of Humming-birds. Although eleven species of this remarkable group have been met with within our limits, the great ma.s.s of the Trochilidae, which are now known to number some 400 species, belong to the Tropics.
The Swifts are also scantily represented by a single species. The Caprimulgidae are comparatively more abundant, but slightly below the average in number of species.
The Argentine Woodp.e.c.k.e.rs enumerated in the present work are thirteen in number, but several of those are somewhat doubtful species, and others only occur in the extreme northern limits of the Republic. On the whole we may say that the _Pici_ are decidedly deficient in Argentina.
Nine families of the fourth order, Coccyges, are included in the Neotropical Avifauna, but of these only five are represented in the Argentine Ornis--the Motmots, Todies, Jacamars, and Barbets being entirely wanting. The Trogons, Puff-birds, and Toucans are also essentially Tropical forms, and have but one or two representatives on the northern outskirts of the Republic; so that the Cuckoos and Kingfishers are the only two families of Coccyges which play any material _role_ in the Argentine Ornis.
Of the order of Parrots it will be seen from our Table that 142 species are known as belonging to the Neotropical Region, and that only ten of these have been met with within our limits. Of these ten, moreover, several are either doubtful, or only occur on the northern outskirts of Argentina, so that Parrots must be held to be deficient in the Argentine Ornis. As is well known Parrots are mostly inhabitants of the Tropics, and it is quite an exception to the rule that several of these warmth-loving birds should extend into the cold lat.i.tudes of Patagonia and Chili. This, however, is paralleled in the Old World by the existence of Parrots in some of the Antarctic Islands south of New Zealand.
Of the Birds of Prey of the Argentine Republic, Diurnal and Nocturnal, it is not necessary to say much; both of these orders are rather in excess as regards the average number of species, the Accipitres especially so. The wide open pampas offer a fine field for Kites and Buzzards and their kind, and they are as numerous in individuals as in species in such favoured haunts.
In the next order, Steganopodes, the Argentine Ornis seems to be very deficient. Out of the five families of this group which occur in the Neotropical Region, one only is yet known to us to be represented in the Argentine Ornis, and that by a single species. But when the sea-birds of the Argentine coast-land come to be better known, there is no doubt that several additions will be made to the list.
The next following order, Herodiones, is of much more importance in Argentine Ornithology, not less than 19 species of this group being already known to exist within our limits, out of a total of 44 Neotropical species. And amongst these we can pick out the little Variegated Bittern (_Ardetta involucris_) and the four species of Ibises as being highly characteristic members of the Argentine Ornis.
The tenth order, that of Anseres, or Waterfowl, commonly so-called, is also largely in excess as regards the number of species. Out of a total of 64 Anseres belonging to the Neotropical Regions, 23 are met with in the Argentine Republic. Moreover, the greater number of these are exclusively Antarctic species, restricted to the Patagonian Subregion.
Amongst them we may specially call attention to the Black-necked Swan (_Cygnus nigricollis_), the Chiloe Wigeon (_Mareca sibilatrix_), and the Rosy-billed Duck (_Metopiana peposaca_) as highly characteristic and ornamental species.
Proceeding to the next order, that of the Pigeons (Columbae), we find the number of Argentine species to be slightly below the average. Several fine Pigeons and Doves are well-known inhabitants of the Republic, but the Columbine order is not a prominent one within our limits.
The Gallinaceous birds of the Neotropical Region are about ninety in number, the greater part of these belonging to the Cura.s.sows, Cracidae, a family specially adapted for habitation in the extensive forests of the New World. Four species of Cracidae have been met with in the forest-region of Northern Argentina; but the Gallinaceous group as a whole must be held to be deficient in this part of South America, the place in Nature which these birds fill in other regions being occupied here by the more lowly organized Tinamous, of which we shall speak further on.
The Geranomorphae of the Argentine Republic are much in excess as regards the number of species. This arises mainly from the abundant supply of Rails and Crakes which Nature has provided for the more swampy districts of the pampas, and to the presence of no less than three distinct species of Coots (_Fulica_), which appear to be generally abundant on the lakes and pools. Nor must we forget to mention as of special interest the two Cariamas which belong to this order, and which are the only representatives of a family of very peculiar structure. One of the two Cariamas is, so far as we know, absolutely confined to the Northern provinces of the Argentine Republic; the second is a bird of the campos of Southern Brazil, which only just comes within our limits.
The Snipes and Plovers and their allies, const.i.tuting the Order Limicolae, are again in excess in the Argentine Avifauna, not less than 25 out of a known total of 73 Neotropical species having been already met with within our limits. A large proportion, however, of these birds are merely winter visitors, and breed only in the far north. On the other hand, the Slender-billed Plover (_Oreophilus ruficollis_) and the Winter Plover (_Eudromias modesta_) are species highly characteristic of the Patagonian subregion, and come to the neighbourhood of Buenos Ayres from a contrary direction. Another especially characteristic Patagonian family of this order is the Thinocoridae or Seed-Snipes, of which two species occur within our limits.
Of the Gaviae, or Gulls and Terns, of the Argentine Republic, nine species are already known out of a total of 53 Neotropical members of the group, and additions no doubt will be made to the list when the coast-birds of La Plata come to be better known.
The seventeenth order of Birds, Pygopodes, is represented in the Argentine Ornis by five species of Grebes. Two of these are widely diffused over all America, the remaining three are Antarctic species belonging to the Patagonian subregion. As only nine species of this groups are known to occur in the whole Neotropical Region, the Pygopodes are highly in excess in the Argentine Avifauna.
The Impennes, or Penguins, which form the eighteenth order of birds, according to the arrangement of the "Nomenclator," are a group specially characteristic of high Antarctic lat.i.tudes. Nine species of Penguins occur on the coasts of Antarctic America, but one of these only is as yet known to reach so far north as our limits.
We now come to the Crypturi or Tinamous, an order of birds commonly supposed to be Gallinaceous, and generally confounded with "Partridges"
and "Pheasants" in the vernacular. They are, however, in some points of essential structure more nearly allied to the Struthiones, although they doubtless fill the same place in the economy of Neotropical Nature as the true Gallinaceous birds in other lands. The Tinamous are spread all over the Neotropical Region and number about 36 species. Eight of these occur within the Argentine Republic; and amongst them we may pick out the Martineta Tinamou (_Calodromas elegans_) and the three species of the genus _Nothura_ as being specially characteristic Patagonian types.
Lastly, we come to the final order of the Neotropical Ornis in the shape of the Rheas, or the American representatives of the Ostrich-type of bird-life. The Rhea is, above all other birds, a most characteristic representative of the Avifauna of the Patagonian subregion. It is true that it ranges far north throughout the campos of Inner Brazil, where the outlying members have become developed into an almost distinct species or subspecies, _Rhea americana macrorhyncha_. But south of the Rio Negro of Patagonia another very distinct type of Rhea, almost subgenerically different, is met with and extends thence to the Straits of Magellan. _Rhea_ has also been lately ascertained to occur on the western side of the Andes in the Chilian province of Tarapaco; so that this fine form of bird-life is diffused nearly over the entire Patagonian subregion, and is well ent.i.tled to be termed one of the most characteristic features of the Patagonian Avifauna.
In conclusion, therefore, we may sum up our present knowledge of the Argentine Avifauna somewhat as follows:--
The Argentine Avifauna comprises 434 species of birds, referable to 54 families and genera.
All the twenty Orders of the Neotropical Avifauna have representatives within its boundaries, except the _Opisthocomi_ or Hoatzins, which are restricted to the Amazonian subregion.
The most numerous families of the Argentine Avifauna are, among the Pa.s.seres, the Finches with 46 species, the Tyrants with 63 species, and the Wood-hewers with 46 species. Among the remaining Orders, the Diurnal Birds of Prey with 19 species, the Waterfowl with 22 species, the Rails with 13 species, the Snipes with 15 species, and the Tinamous with 8 species, are likewise well represented.
Genera characteristic and proportionately numerous in species in the Argentine Avifauna are _Poospiza_ and _Phrygilus_ among the Finches, _Taenioptera_ and _Cnipolegus_ among the Tyrants, _Synallaxis_ among the Wood-hewers, _Fulica_ among the Rails, and _Nothura_ among the Tinamous.
Less numerous in species, but highly characteristic forms of the Argentine Ornis, are _Thinocorus_, _Rhynchotis_, and _Rhea_.
The following ten genera, mostly monotypic, are, so far as we know at present, restricted to the limits of the Argentine Avifauna or its immediate confines:--_Donacospiza_ and _Saltatricula_ (Fringillidae); _Coryphistera_, _Anumbius_, _Limnornis_, and _Drymornis_ (Dendrocolaptidae); _Rhinocrypta_, with two species (Pteroptochidae); _Spiziapteryx_ (Falconidae); _Chunga_ (Cariamidae); and _Calodromas_ (Tinamidae).
ARGENTINE ORNITHOLOGY.
Order I. Pa.s.sERES.
Suborder I. _OSCINES._