Bulletin - United States National Museum - si-pddr - Smithsonian ...

BIRDS OF AEGENTINA, PARAGUAY, URUGUAY, AND CHILE 97
two handsomely marked eggs. As I examined these and packed
them in my hat to remove them both caracaras hovered with harsh
grating calls a few feet above my head. The ground color of these
eggs varies from light-pinkish cinnamon to pinkish cinnamon, obscured
and in places almost obliterated by a heavy irregular wash
that varies from auburn and chestnut to hessian brown and liver
brown. About the large end these blotches become heavier and more
concentrated, and in places are almost black. These eggs measure
59.8 by 48 mm. and 54.5 by 48.5 mm. A caracara was gathering
sticks for a nest on November 15.
A few were observed near San Vicente, Uruguay, from January
26 to February 2, 1921, and one was seen at Lazcano on February
7. North of Cordoba, Argentina, many were noted along the rail-
road on March 31 and at Tapia, Tucuman, the species was fairly
common from April 7 to 13. A few were recorded on the slopes
of the Sierra San Xavier, above Tafi Viejo, on April 17.
On my return from Paraguay to the pampas of Buenos Aires I
noted that the carrancho of the south seemed larger than that ob-
served a fevr days previous in the northern Chaco, an impression
that has been sustained by a study of specimens. Skins from Chile
(one) and Argentina from the Straits of Magellan northward
(nine) show a wing measurement that varies from 410 to 442 mm.
(average 431 mm.). Skins from Brazil (Pernambuco, and one
from Bahia or Rio de Janeiro) and Puerto Pinasco, Paraguay
(three in all) range from 365 to 405 mm. (average 387 mm.).
(There seems to be no constant difference in size correlated with sex
in the caracaras.) The large form apparently ranges throughout
Argentina as I killed an adult female at Las Palmas, Chaco, on
July 20, 1920, with a wing measurement of 429 mm.) and into
Paraguay as a bird from that country without definite locality
(taken on the Page expedition in the fifties) has the wing 425 mm.
As the type locality of Miller's Falco plancus has been cited by
Shaw^^ as Tierra del Fuego, the southern form will stand as
Polyhorus plancus plancus.
POLYBORUS PLANCUS BRASILIENSIS (Gmelin)
Falco trasiliensis Gmelin, Syst. Nat., vol. 1, pt. 1, 17SS, p. 262. (Brazil.")
As has been stated aboA'e a male caracara secured at Kilometer
80, west of Puerto Pinasco, Paraguay, on September 15, 1920, has
a wing measurement of 405 mm., and so appears to belong to the
northern form, for which the name Falco hrasiliensis of Gmelin
is available. This is assumed to be the form that ranges from
'sCim. Phys., 1796, p. 34.
Type locality hereby fixed as Pernambuco.