BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 379 



has described a large bird from Bolivia/^ which must stand as 

 GnoHmopsar c. megistus (one skin seen in United States National 

 Museum), but which can have no relation to the bird of almost 

 equal size from far distant Uruguay. Gnorinwpsar sulcirostris 

 (Spix) said doubtfullj'^ to come from Minas Geraes, according to 

 Hellmayr," is a distinct species with a wing measurement of 155 

 mm. The Uruguayan skin is listed here with these comments, though 

 it can not be considered typical chopi. 



The chopi or tordo (the latter a name shared with the cowbird) 

 was partial to marshy meadows where it fed in little bands that 

 flew up at intervals with musical calls to rest in the sun in scattered 

 clumps of trees. It was not unusual to see them at dusk in flight 

 to a roost in some reed bed, and it was reported that bands gathered 

 in late summer in such numbers as to damage fields of corn. Though 

 their ordinary call was a harsh chuck^ when several were gathered 

 they uttered slow whistled calls that formed a pleasing medley. 

 They much resembled grackles in their direct flight and general 

 habits. Near Puerto Pinasco they came about dwellings and ranch 

 buildings to investigate garbage cast out from the kitchen, varying 

 their search for food by whistled concerts from near-by shade trees. 



By the middle of August males Avere seen circling with set wings 

 in short spirals before females, and by the end of September they 

 had scattered to breeding grounds. In January, in eastern Uruguay, 

 I found them among groves of palms where they seemed to be nest- 

 ing as they scolded with rattling calls, while they walked about 

 on the palm fronds overhead or occasionally gave a burst of song. 



An adult male, taken September 18, had the bill, tarsus, and toes 

 black, and the iris Hay's brown. The genus is remarkable for the 

 sharply rounded ridge that passes obliquely across the base of the 

 mandible. 



AGELAIUS TmLIUS CHRYSOPTERUS Vieillot 



Arielaius chrysoptenis Vieillot, Nouv. Diet. Hist. Nat., vol. 34', 1819, p. .539. 

 (Paraguay.) 



The yellow-shouldered blackbirds of the west coast and the An- 

 dean region from Chile (the type-locality of Turdus thilius of 

 Molina ^^) north to Galea, Peru, have the wing distinctly longer than 

 those from east of the Gordillera. Average measurements of four 

 males from Ghile are, wing, 94; tail, 63.5 mm. ; of three females, wing, 

 86; tail, 67.8 mm. Eleven males from Argentina (Buenos Aires and 

 Santa Fe) measure, wing, 85.1; tail, 65.6 mm.; seven females, wing, 

 79.6; tail, 60.4 mm. These differences are sufficient to warrant the 



"4p7io6MS megistus Levcrkiilin, Journ. fiir Orn., 1889, p. 104. (Santa Cruz and 

 San Miguel, Bolivia.) 



T*Abh. Kon. Bayerischen Al^ad. Wiss., Kl. 2, vol. 22, Abt. 3, 1906, pp. 614-615. 

 " TwrfZifs Thilius, SajiR. Stor. Nat. Chili, 1782. p. 250. 



