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Behavior of the Grassland Sparrow and Two Species of Seed-Finches

1974; Oxford University Press; Volume: 91; Issue: 1 Linguagem: Inglês

10.2307/4084659

1938-4254

Alan Lill,

Wildlife Conservation and Criminology Analyses

The behavior of many of the predominantly granivorous neotropical bird species conventionally grouped under the familial heading Fringillidae in field guides is poorly known.Documenting it may help promote a better understanding of the phylogeny and systematics of these birds and clarify the evolution and adaptive significance of their social systems.It thus seems worthwhile to report some brief observations I made on the territorial behavior and feeding habits of Grassland Sparrows (Myospiza humeralis), Large-billed Seed-Finches (Oryzoborus crassirostris), and Lesser Seed-Finches (O.angolensis) during a short field trip to Guyana in July 1971.The behavior of these species seems not to have been reported in any detail.These observations were an extension of a socioecological investigation of the "finches" of Trinidad and Tobago to be published elsewhere.I use "finch" and "Fringillid" as convenient terms for species listed under the family heading Fringillidae in Meyer de Schauensee (1970a).I spent 35 hours observing these species with the aid of 10 x 50 binoculars at four locations in Guyana. GRASSLAND SPARROWThe Grassland Sparrow is known from both tropical and subtropical zones of South America.Meyer de Schauensee (1970a) lists it as a species inhabiting grassland, Hayerschmidt (1968) records it from open sandy savanna with low grasses and scattered bushes in Surinam, and Snyder (1966) notes its habitat in Guyana as grassland and savanna.The species was common on the campus of the University of Georgetown, a flat, rather damp tract at sea level comprising grassland with some sedges (notably Cyperus articulatus L.), which was apparently mowed at intervals.The only related species commonly observed there was the Chestnut-bellied Seedeater (Sporophila castaneiventris).Grassland Sparrows were also abundant near the Manari River on the Rupununi Savannas of the interior where they occurred in exactly the same habitat as Hayerschmidt (ibid.)lists for Surinam.Cohabiting related species here were the Wedge-tailed Grass-Finch (Emberizoides herbicola) and the Grassland Yellow-Finch (Sicalis luteola), but both these species mainly occupied completely open, bushless savanna adjacent to grasslands the sparrows occupied.I spent 15 hours watching the sparrows at these two locations, mostly in the early morning and late afternoon.