842 BIOTROPICA 32(4b): 842–850 2000 Frugivory by Toucans (Ramphastidae) at Two Altitudes in the Atlantic Forest of Brazil 1 Mauro Galetti 2 Plant Phenology and Seed Dispersal Research Group, Departamento de Ecologia, Universidade Estadual Paulista (UNESP), C.P. 199, 13506-900, Rio Claro, Sa˜ o Paulo, Brazil Rudi Laps and Marco A. Pizo 3 Departamento de Zoologia, UNICAMP, C.P. 6109, 13081-970, Campinas, Sa˜ o Paulo, Brazil ABSTRACT Toucans are prominent components of the tropical American avifauna. Although these birds are very conspicuous, there are few ecological studies focusing on them. In this study, the diets of four sympatric toucans (Ramphastos vitellinus, R. dicolorus, Selenidera maculirostris, and Baillonius bailloni) were assessed by recording feeding bouts at two altitudes in the Atlantic Forest of southeast Brazil. Our results show that toucans are predominantly frugivorous birds (96.5% of the 289 feeding bouts were on fruits). In the lowlands (70 m elev.), only fruits (48 species, 27 families) were recorded, while in the highlands (700 m elev.), toucans were observed feeding on fruits (25 species, 22 families), flowers, leaves, and insects. Non-fruit items were recorded only in the highlands, most of them eaten by B. bailloni. Cecropia glaziovii and Euterpe edulis, two abundant plants in the highland and lowland sites, respectively, and Virola oleifera, a plant that produces lipid-rich arillate fruits, were eaten heavily by the toucans. The number of feeding bouts recorded for R. vitellinus in the lowlands was positively correlated with lipid content of the fruits eaten. The diameters of fruits eaten by toucans varied greatly (range = 0.4–25.0 mm). While the large Ramphastos species not only ate tiny fruits (e.g., Hyeronima alchorneoides) but also large ones (e.g., Virola gardneri), the toucanets ate piecemeal the large fruits that exceeded their gape width, suggesting that gape size did not limit the use of any fruit by the toucans at our study sites. RESUMO Os tucanos formam um importante grupo de aves americanas pelo papel que desempenham como dispersores de sementes. Embora sejam conspı ´cuas, ha´ relativamente poucos estudos ecolo´ gicos sobre estas aves. Neste estudo, a dieta de quatro espe´cies simpa´tricas de tucanos (Ramphastos vitellinus, R. dicolorus, Selenidera maculirostris, and Baillonius bailloni) foi investigada atrave´s do registro de eventos de alimentac¸a˜o em duas a´reas localizadas em diferentes altitudes da Mata Atlaˆntica do sudeste do Brasil. Os resultados mostraram que os tucanos sa˜o aves predoninantemente frugı ´voras (96.5% dos 289 eventos de alimentac¸a˜o registrados foram em frutos). Na a´rea de baixada (700 m a.n.m.), somente frutos (48 espe´cies, 27 famı ´lias) foram registrados na dieta, enquanto na a´rea montana (700 m a.n.m.) os tucanos foram observados alimentando-se de frutos (25 espe´cies, 22 famı ´lias), flores, folhas e insetos. Itens alimentares diferentes de frutos foram registrados somente na a´rea montana, a maioria deles foram consumidos por B. bailloni. Cecropia glaziovii e Euterpe edulis, duas espe´cies de plantas abundantes nas a´reas montana e de baixada, respectivarnente, e Virola oleifera que produz frutos arilados ricos em lipı ´deos, foram altamente consumidos pelos tucanos. 0 nu´ mero de eventos de alimentac¸a˜o registrado para R. vitellinus na a´rea de baixada esteve positivamente correlacionado com o conteu´ do lipı ´dico dos frutos consumidos. Os diaˆmetros dos frutos consumidos pelos tucanos variou consideravelmente (0,4–25,0 mm). Enquanto as espe´cies de maior porte (Ramphastos spp.) consumiram na˜o somente frutos pequenos (e.g., Hyeronima alchomeoides) mas tambe´m frutos grandes (e.g., Virola gardneri), as espe´cies menores (S. maculirostris e B. bailloni) comeram aos pedac¸os os frutos cujos diaˆmetros excederam a largura de seus bicos, mostrando que a largura do bico em si na˜o limita o consumo de nenhum fruto pelos tucanos nas a´reas estudadas. Key words: Atlantic Forest; frugivory; gape size; Ramphastidae; seed dispersal; toucan. 1 Received 13 August 1998; revision accepted 25 Febru- ary 1999. 2 Corresponding author. E-mail: mgaletti@rc.unesp.br 3 Present address: Plant Phenology and Seed Dispersal Research Group, Departamento de Botaˆnica, Universi- dade Estadual Paulista (UNESP), C.P. 199, 13506-900, Rio Claro, Sa˜o Paulo, Brazil. E-mail: pizo@rc.unesp.br RAMPHASTIDAE (TOUCANS AND TOUCANETS) IS AMONG THE OLDEST AVIAN LINEAGES with living descendants (Sibley & Ahlquist 1990), and is the symbol of the tropical American forests. Since naturalists first vis- ited the tropics, toucans have attracted attention due to their large body size, flamboyant colors, and long and bizarre beaks (Bates 1863, Goeldi 1894, Van Tyne 1929, Gould & Rutgers 1972). In spite