HOST RELATIONS OF PARASITIC COWBIRDS 



197 



having reared young shiny cowbirds. This number will undoubtedly 

 increase with further field study. 



It is worth noting that one of the most frequently imposed upon 

 victims, the fork-taHed flycatcher, Muscivora tyrannus, for which 

 some 57 records of parasitism are available, has not yet been reported 

 as having reared the parasitic young. In this species the earher 

 observations, especially those of Hudson (1874, pp. 153-154), indi- 

 cated that the much harassed flycatcher frequently deserted its nest 

 because of excessive parasitism; in some instances its own eggs were 

 outnumbered 3 to 1 by those of the parasite. 



rufous ovenbird, Furnarius rufus 

 firewood gatherer, Anumbius anumbi 

 white-naped ant shrike, Sakesphorus 



bernardi 

 white-headed marsh tyrant, Arundi- 



nicola leucocephala 

 short-tailed ground tyrant, Musci- 



gralla brevicauda 

 bellicose tyrant, Tyrannus vielan- 



cholicus 

 reed tyrant, Pseudocolopierix flavi- 



ventris 

 South American house wren. Troglo- 

 dytes muscidus 

 Patagonian mockingbird, Mimus pata- 



gonicus 

 long-tailed mockingbird, Mimus 



longicaudatus 

 calandria, Mimus saturninus 

 white-banded mockingbird, Mimus 



triurus 



dusky thrush, Turdus amaurochaUnns 

 red-bellied thrush, Turdus rufiventris 

 brush gnatcatcher, Polioptila dumicola 

 bicolored ateleodacnis, Ateleodacnis 



bicolor 

 golden warbler, Dendroica petechia 

 Swainson's grackle, Holoquiscalus 



lugubris 

 Grace's oriole, Icterus grace-annae 

 blue and yellow tanager, Thraupis 



bonariensis 

 grayish saltator, Saltator coerulescens 

 orange-billed saltator, Saltator auran- 



tiirostris 

 screaming seedeater, Sporophila caeru- 



lescens 

 Diuca finch, Diuca diuca 

 Chingolo sparrow, Zonotrichia capensis 

 black and chestnut warbling finch, 



Poospiza nigro-rufa 



New information on the life histories of Neotropical birds accumu- 

 lates very slowly compared with the rate of progress in our knowledge 

 of the systematics and distribution of these creatures. In view of 

 the paucity of observers in South America, it is all the more pleasant 

 to be able to note and extract interesting data from two important 

 and recently published studies from opposite sides of that continent. 

 Marchant (1958, 1960) has brought to the attention of ornithologists 

 the first information available on the brood-hosts of the Ecuadorian 

 race of the shiny cowbird (M.6. aequatorialis), and Sick and Ottow 

 (1958) have made a significant study of this parasite and the chingolo 

 sparrow, its chief victim, in southeastern Brazil. In addition to 

 these, Ottow and Hoy (mss., 1961) have made interesting studies in 



