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

taken) ;
BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 349
Mendoza, Mendoza, March 13; Potrerillos, Mendoza, March
15 to 21 (five immature specimens) ; Timuyan, Mendoza, March
22 to 29 (immature female) ; Concon, Chile, April 24 to 27 (two).
House wrens seen at General E,oca, Rio Negro, November 23 to
December 3, may also have been this form.
CISTOTHORUS PLATENSIS PLATENSIS (Latham)
Sylvia platensis Latham, Index Orn., vol. 2, 1790, p. 548. (Buenos
Aires.
)
At Lavalle, Buenos Aires, four adult males were taken October
23, 1920, while at Tunuyan, Mendoza, a series of 10, all immature
(both sexes represented), was secured between March 23 and 28,
1921. Hellmayiy in a review of this species, considers that tyj^ical
platensis ranges from Bahia Blanca north to Santa Elena, Entre
Eios, and west to Mendoza, Of the present series the skins from
near the mouth of the Kio Ajo, at Lavalle, may be considered as
topotypical of Latham's platensis from " Bonaria." The skins from
the Province of Mendoza are different, but as all are young must
be allotted to 2)Iate7isis until adult specimens may be examined.
All of the birds from Tunuyan appear slightly more heavily
streaked above, and have the dark tail bars broader than skins
from Lavalle. Half of those seen have the rump plain brownish
and the streaks on the crown nearly obsolete. In the remainder
the head is distinctly lineated; the back marldngs are heavier and
extend down over the rump. In a way these specimens appear
intermediate between C. p. homensis, which is very heavily marked
above from neck to upper tail coverts, and is strongly rufescent,
and platensis but are nearer the latter. It is probable that Cisto-
thoims fasciolatus Burmeister*^ may prove a valid subspecies.
At Lavalle, Buenos Aires, I found a small colony of these marsh
wrens in low growths of dead rushes at the border of a tidal marsh,
where attention was attracted by their tinkling songs tu-tu-tu tee-tee-
tee ter-ter-ter tsee-ee-ee-ee^ each triplet being pitched in a slightly
different key, while the whole terminated in a metallic music-box
rattle. As the birds sang from the tops of rushes they were easily
located by their light breasts, but as I approached they dropped down
into heavy cover which they often refused to leave in spite of
various attractive noises, from the usual squeak to the low clinking of
a brass shell against a gun barrel, made to excite their curiosity.
Their flight was undulating, often at a height of li/^ to 2 meters
above the marsh. Near Tunu3'an, Mendoza marsh wrens were en-
«Nov. Zool., vol. 28, September, 1921, p. 250.
*i Journ. fur Ornith., 1860, p. 2.52. (Mendoza.)
54207—26 ^23