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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 403
Museum, I agree with Hellmayr^ that typical arvensis ranges from
Matto Grosso and Rio Grande do Sul south to northern Patagonia
(General Eoca and Bariloche, Eio Negro) and Chile. Males from
Chile are very slightly larger (wing, 75.6-78 mm.) than those from
Brazil and central to 'northern Argentina (wing, 71-76 mm.), but
the difference is too slight to merit distinction, S. a. luteola Sparr-
man,^ of more northern range, is smaller and brighter colored.
Sicalis chapTnani Ridgway, from Santarem on the lower Amazons,
is apparently a distinct species and not a subspecies of arvensis, as it
has a much larger, heavier bill with a more strongly curved culmen.
During the breeding season the misto is found about clumps of
bunch grass or saw grass near streams -or marshes or. in irrigated
sections, about alfalfa fields where it often gathers in little colonies.
Males sing from perches in the grass or rise a few feet and scale
doArn witli long wings fully spread, while they utter their low, tremulous
notes. Often before resting they rise to repeat the performance
a second time, or sail about in erratic circles. The wings during
this performance are fully spread and extended forward. Breeding
colonies were observed at Lavalle, Buenos Aires, in November;
at General Roca, Rio Negro, at the end of the same month: and at
Carliue, Buenos Aires, the middle of December. A bird in juvenal
plumage was taken at San Vicente, Urugua3^ January 27. Two
nests found near Carhue, December 18, contained four fresh eggs,
and another on the same date held five young a week old. The nests,
placed from 300 to 400 mm. from the ground, in clumps of stiffstemmed
grass, were cup-shaped structures made of fine grasses*
lined with coarse hair from the manes and tails of horses. The eggs
are white, tinged faintly with grayish green, with spots of Mars and
chestnut brown, distributed over the egg, but concentrated heavily
about the large end. The two sets taken differ considerabh', as one
is large and heavily blotched, while the other is smaller, rounder,
and has much finer markings. The larger set measures 17.4 by 13.4,
17.5 by 13.2, 17.6 by 13.3, and 18.1 by 13.4 mm. The second set
measures 16.1 by 13.7, 16.2 by 13.4, 16.3 by 13.6, and 16.5 by 13.6 mm.
The eggs are fragile and thin shelled. (PI. 20.)
SICALIS LUTEA (d'Orbigrny and Lafresnaye)
Emberisa lutea, (I'Oebigny and Lafkesnaye, Mag. Zool., 1837, cl. 2, p. 74^
(Summis Andibus, Bolivia.)
The statement of Todd^ that the yellow finches of Middle and
South America must be grouped in one genus, Sicalis, is substan-
'Nov. Zool., vol. 1.5, June, 1908, p. 34.
'According to Hartert, Vog. Pal. Fauna, Naclitr. 1, September, 1923, Emheriza lutcolw
Sparrman, 1789, refers to the form known currently as Sicalis a. minor Cabanis.
Ann. Carnegie Mus., vol. 14, October, 1922, p. 519.