Abstract
We studied the feeding ecology of two species of sympatric warblers, Basileuterus leucoblepharus and Basileuterus culicivorus, in the province of Chaco, Argentina, by analyzing their diet, foraging techniques and vertical distribution. Sampling was conducted between December 2001 and September 2002 in the riparian forest of the Paraná River floodplain. Basileuterus leucoblepharus captured their prey mainly gleaning on the ground and in the herbaceous layer, and rarely over 1 m high. Basileuterus culicivorus, on the contrary, captured prey in the undercanopy and shrub strata, mainly between 1.5–2 m high, using several foraging techniques (mainly reachout, reach-up and hang-sideways). We recorded 9 prey items for Basileuterus leucoblepharus and 12 for Basileuterus culicivorus. Stomachs of Basileuterus leucoblepharus showed a numerical and volumetric predominance of Curculionidae, followed in importance by other unidentified Coleoptera. In Basileuterus culicivorus, Bruchidae and Curculionidae were numerically important, while Lepidoptera was volumetrically important. We found some diet overlap in these species, although their coexistence would be possible by their differences in the use of foraging techniques and in the vertical distribution within the riparian forest.
References
BELTON W (1994) Aves silvestres do Rio Grande do Sul:distribução e biologia. Ed. Unisinos, San Leopoldo
BREWER MM Y ARGUELLO NV (1980) Guía ilustrada deinsectos comunes de la Argentina. Fundación MiguelLillo, San Miguel de Tucumán
BUCHER EH Y CHANI JM (1998) Región 2: Chaco. Pp.75–96 en: CANEVARI P, BLANCO DE, BUCHER E, CAS-TRO G Y DAVIDSON I (eds) Los humedales de laArgentina. Clasificación, situación actual, conservacióny legislación. Wetlands International, Buenos Aires
BURMEISTER H (1856) Systematische uebersicht der thiereBrasiliensis. Volume 3 (Aves, Zweiter Theil). G Reimer,Berlín
CAPLLONCH P (2007) Distribución latitudinal yaltitudinal de tres especies del género Basileuterusen el noroeste argentino. Hornero 22:23–28
CHATELLENAZ ML (2005) Aves del valle del Río Paranáen la Provincia del Chaco, Argentina: Riqueza,Historia Natural y Conservación. INSUGEO,Miscelánea 14:527–550
DUNHAM AE (1983) Realized niche overlap, resourceabundance and intensity of interspecific competi-tion. Pp. 261–280 en: HUEY RD, PIANKA ER YSCHOENER TW (eds) Lizard ecology. Studies of a modelorganism. Harvard University Press, Cambridge
ESKUCHE U (1984) Vegetationsgebiete von Nord-undMittelargentinien. Phytocoenologia 12:185–199
ESKUCHE U (2004) La vegetación de la vega del ríoParaná Medio superior, Argentina. Folia Botanica etGeobotanica Correntesiana 17:1–60
FITZPATRICK JW (1985) Form, foraging behaviour, andadaptive radiation in the Tyrannidae. OrnithologicalMonographs 36:447–470
FONTANA JL (1991) Las comunidades vegetales de unalaguna chaqueña del valle del Río Paraná. FoliaBotanica et Geobotanica Correntesiana 6:1–17
FORSTMEIER W Y KEßLER A (2001) Morphology andforaging behaviour of Siberian Phylloscopus war-blers. Journal of Avian Biology 32:127–138
LEVINS R (1968) Evolution in changing environments:some theoretical explorations. Princeton UniversityPress, Princeton
MAGURRAN AE (1989) Diversidad ecológica y su medi-ción. Ed. Vedrà, Barcelona
MARINI MA Y CAVALCANTI RB (1993) Habitat andforaging substrate use of three Basileuterus warblersfrom Central Brazil. Ornitología Neotropical 4:43–57
MENDOÇA-LIMA A, HARTZ SMY KINDEL A (2004) Forag-ing behavior of the White-browed (Basileuterusleucoblepharus) and the Golden-crowned (B.culicivorus) warblers in a semidecidual forest insouthern Brazil. Ornitología Neotropical 15:5–15
OLROG CC (1979) Nueva lista de la avifauna argentina.Opera Lilloana 27:1–324
ORFEO O (1996) Geomorfología del sistema fluvialParaguay-Paraná en el área de su confluencia.Pp. 131–147 en: ASOCIACIÓN GEOLÓGICA ARGEN-TINA (ed) Actas del XIII Congreso GeológicoArgentino y III Congreso de Exploración de Hidro-carburos. Tomo 4. Asociación Geológica Argen-tina e Instituto Argentino del Petróleo, BuenosAires
DELA PEÑA MR (1999) Aves argentinas. Lista y distribu-ción. LOLA, Buenos Aires
PIANKA ER (1986) Ecology and natural history of desertlizards. Princeton University Press, Princeton
POPOLIZIO E (1970) Algunos rasgos de la geomor-fología del nordeste argentino. Boletín de la SociedadArgentina de Botánica 11:17–35
RAKOTOMANANA H (1998) Negative relationshipbetween relative tarsus and wing lengths in Mala-gasy rain forest birds. Japanese Journal of Ornithology47:1–9
REMSEN JV Y ROBINSON SK (1990) A classificationscheme for foraging behavior of birds in terrestrialhabitats. Studies in Avian Biology 13:144–160
RICHARDS OW Y DAVIES RG (1984) Tratado de ento-mología Imms. Volumen 2. Clasificación y biología. Ed.Omega, Barcelona
ROUGÉS M Y BLAKE JG (2001) Tasas de captura y dietasde aves del sotobosque en el Parque Biológico Sie-rra de San Javier, Tucumán. Hornero 16:7–15
SCHUBART O, AGUIRRE AC Y SICK H (1965) Contribuçãopara o conhecimento da alimentação das avesbrasileiras. Arquivos de Zoologia 12:95–249
SHORT LL (1975) A zoogeographic analysis of theSouth American Chaco avifauna. Bulletin of theAmerican Museum of Natural History 154:163–352
SICK H (1985) Ornitologia brasileira. Uma introduçao. Ed.Universidade de Brasilia, Brasilia
SILVA WR (1991) Padrões ecológicos, bioacústicos,biogeográficos e filogenéticos do complex Basileuterusculicivorus (Aves, Parulidae) e demais espécies brasileirasdo gênero. Tesis de Doctorado, Universidad deCampinas, San Pablo
STILES G, SKUTCH A Y GARDNER D (1998) Guía de aves deCosta Rica. Instituto Nacional de Biodiversidad,Heredia

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.