BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 233 



or more were noted and 5 were collected. These birds present a 

 strange appearance in the air, as their long, thin, narrow wings 

 seem as broad at the tip as near the body, while in color they appear 

 wholly light-brownish gray or wdiite, veritable ghosts of birds with 

 wings barely thicker than paper. During the strong wind that pre- 

 A^ailed they sailed constantly with set wings cutting the air rapidly ; 

 when one did choose to fly, it passed with lightninglike speed. 

 Males and females, the latter paler in color on the back, were taken, 

 and I supposed that the birds had drifted across from breeding sta- 

 tions on the high rock escarpment on the southern side of the valley. 

 Frequently they Avere seen in trios. Others of these swifts were 

 recorded about a rocky point in the valley of the Rio Blanco at 

 Potrerillos, Mendoza, on March 18, 19, and 20, 1921. From about 

 30 that were seen, 4 were taken on March 18 and 1 on the day fol- 

 lowing. The call of this species is a high-pitched laughing chatter 

 that does not carry far in the wind. 



Immature birds, as represented in the fall series, have the forehead 

 darker than adults secured in spring and are somewhat more buffy 

 below. Young females are somew^hat darker on the back than those 

 taken in spring, but are still noticeably paler than males. 



This swift does not appear to have been recorded previously south 

 of the Province of Mendoza. 



STREPTOPROCNE ZONARIS (Shaw) 



Hirundo zonaris Shaw, Cim. Phys., 179G, p. 100, pi. 55. (Chapada, Matto 

 Grosso," Brazil.) 



The collared swift was recorded above Mendoza, Mendoza, on 

 March 18, 1921, and on the slopes of the Sierra San Xavier above 

 Tafi Viejo, Tucuman, on April 17. No specimens were secured. 



CHAETURA ANDREI MERIDIONAUS Hellmayr 



Chaetura andrei meridionaUs, Hellmaye, Bull. Brit. Orn. Club, vol. 10, Mar. 

 30, 1907, p. 63. (Isca Yacu," Santiago del Estero, Argentina.) 



The present species was found only in the vicinity of Puerto Pin- 

 asco, Paraguay, where an adult female was taken September 20, near 

 Kilometer 80, and a male September 23, near Kilometer 110 (the 

 latter preserved as a skeleton). Swifts were found over the forest in 

 certain localities, where they seemed to have selected breeding sta- 

 tions in hollow trees. Though seen on September 1 near the low hill 

 at Kilometer 25, arid on September 30 over the Cerro Lorito on the 

 E.io Paraguay, I found them also in certain areas in the level country. 



11 Doctor Chapman's action (BuU. Aroer. Mus. Nat. Hist., vol. 33, Nov. 21, 1914, p. 605) 



in selecting Chapada, a point far distant from the coast, as the type locality of Shaw's 

 Hirundo zonaris, may perhaps be questioned, since it is doubtful If interior specimens had 

 been seen or described as early as 1796. 



" See Dabbene. El Hornero, vol. 1, 1917, p. 7. 



