208 U.S. NATIONAL MUSEUM BULLETIN 233 



aequatorialis) . In the Santa Elena peninsula of southwestern Ecuador 

 Marchant (1958, p. 384; 1960, p. 380) found two parasitized nests. 

 He also saw, on one occasion, a fledged young cowbird being attended 

 by one of these mockingbirds (1960, p. 584). The nominate race of 

 the long-tailed mockingbird was previously known as a host of the 

 shiny cowbird (subspecies M.h. occidentalis) in Peru (Friedmann, 

 1943, p. 351). 



White-banded Mockingbird 



Mimus triurus (Vieillot) 



Already known as a common victim of the shiny cowbird in Men- 

 doza and San Luis provinces, the white-banded mocldngbird was 

 noted as the most frequently imposed upon fosterer in Pampa province 

 as well, according to Pereyra (1937, p. 289). The frequency with 

 which the shiny cowbird parasitizes mockingbirds in Argentina is a 

 puzzhng contrast to the tendency of the brown-headed cowbird to 

 leave the North American mockingbird unmolested in the southern 

 United States. 



Chilean Robin 



Turdus falklandii Quoy and Gaimard 



R. Barros Valenzuela (1956, p. 92) has recorded the Chilean sub- 

 species of this thrush, T.f. magellanicus, as a victmi of the shiny cow- 

 bird in Chile. This is an addition to the known hosts. In view of 

 the recent spread of the shiny cowbird in various parts of central 

 Chile, it may be anticipated that additional hosts will be reported 

 from that coimtry. 



Spix's Thrush 

 Turdus leucomelas (Vieillot) 



To the few earlier records of the northern race of this thrush {T.l. 

 albivenier) as a host of the Venezuelan subspecies of the shiny cow- 

 bird {M.b. venezuelensis) may be added another — a nest with 2 eggs 

 of the host and 2 of the parasite. This was found at Casa Blanca, 

 Venezuela, on April 17, and was recorded by GiUiard (1959, p. 26), 

 who wrote that this thrush is frequently imposed upon in that area. 



Brush Gnatcatcher 



PoUoptila dumicola (Vieillot) 



In my original study (1929, p. 110), I noted that, while Hudson had 

 listed this gnatcatcher as a victim of the shiny cowbird in Argentina, 

 he gave no specific records or details. Harrison (1950, p. 6) now has 

 published a definite record, which removes the earlier uncertainty 

 attached to this bird as a molothrine host. The nominate race of 

 both the host and the parasite are involved here. 



