ABSTRACT
We studied stomachs contents of 50 specimens of four common cuckoo species (Cuculidae) from southern Brazil: Guira guira (Gmelin, 1788) (n = 21), Coccyzus melacoryphus (Vieillot, 1817) (n = 8), Crotophaga ani (Linnaeus, 1758) (n = 11), and Piaya cayana (Linnaeus, 1766) (n = 10). We measured stomach volume and prey were identified and quantified based in their dimensions. The size of the prey was associated with bill width and body mass. Diet items were analyzed and identified to the lowest possible taxonomic level, based on literature, scientific collection data, and specialists. The diet of the four species was composed by 100% animal species, with invertebrate dominance. Only in G. guira stomachs the presence of vertebrates was observed more than once (amphibian, reptile, and bird). C. ani, which had similar diet, ingested a large number of Arachnida and Orthoptera. Piaya cayana ate mostly Hemiptera. The predominance of caterpillars (Lepidoptera), suggested in the literature was not observed in the diet of C. melacoryphus. There was a statistically significant difference in bill width and body mass among the bird species, and there was no correlation between bill width and the proportion of medium and large-sized prey.
ABSTRACT
We studied stomachs contents of 50 specimens of four common cuckoo species (Cuculidae) from southern Brazil: Guira guira (Gmelin, 1788) (n = 21), Coccyzus melacoryphus (Vieillot, 1817) (n = 8), Crotophaga ani (Linnaeus, 1758) (n = 11), and Piaya cayana (Linnaeus, 1766) (n = 10). We measured stomach volume and prey were identified and quantified based in their dimensions. The size of the prey was associated with bill width and body mass. Diet items were analyzed and identified to the lowest possible taxonomic level, based on literature, scientific collection data, and specialists. The diet of the four species was composed by 100% animal species, with invertebrate dominance. Only in G. guira stomachs the presence of vertebrates was observed more than once (amphibian, reptile, and bird). C. ani, which had similar diet, ingested a large number of Arachnida and Orthoptera. Piaya cayana ate mostly Hemiptera. The predominance of caterpillars (Lepidoptera), suggested in the literature was not observed in the diet of C. melacoryphus. There was a statistically significant difference in bill width and body mass among the bird species, and there was no correlation between bill width and the proportion of medium and large-sized prey.
ABSTRACT
The importance of Lauraceae fruits has been reported on the diet of several birds, mainly from the Ramphastidae, Cotingidae and Trogonidae families. The objectives of this study were to determine which birds consume the fruits of Nectandra megapotamica (Spreng.) Mez (Lauraceae) in a deciduous seasonal forest and, based on the analysis of some of the qualitative and quantitative dispersal components, infer which birds can act as dispersers of the seeds. The study was carried out at the Campo de Instrução de Santa Maria (CISM) (29º43'S, 53º42'W), in the vicinity of Santa Maria, in Rio Grande do Sul State, Brazil. In a total of 70 hours of focal observation, 726 visits of 21 bird species were registered. The birds considered as potential dispersers of N. megapotamica were Turdus albicollis Vieillot, 1818, T. rufiventris Vieillot, 1818, Pitangus sulphuratus (Linnaeus, 1766) and T. amaurochalinus Cabanis, 1850 among the residents, and Tyrannus savanna Vieillot, 1808 and Myiodynastes maculatus (Müller, 1766) among the migratory ones. Generalist birds seemed to enhance the dispersal of N. megapotamica, since they consumed the entire fruits, realized short visits (shorter than 3 minutes) and presented high frequency of visits which, in turn, is related to a higher rate of fruit removal. Nectandra megapotamica shows features that allow it to be included in the generalist dispersal system, except for the high nutritional level of its seeds.
A importância dos frutos de Lauraceae tem sido relatada na dieta de muitas aves, principalmente das famílias Ramphastidae, Cotingidae e Trogonidae. Os objetivos deste estudo foram determinar quais espécies de aves consomem os frutos de Nectandra megapotamica (Spreng.) Mez (Lauraceae) numa área de Floresta Estacional Decidual e, com base na análise de alguns dos componentes qualitativos e quantitativos da dispersão, inferir quais aves podem atuar como dispersores de suas sementes. O estudo foi desenvolvido no Campo de Instrução de Santa Maria (CISM) (29º43'S, 53º42'W), município de Santa Maria, Rio Grande do Sul. Num total de 70 h de observação focal, foram registradas 726 visitas de 21 espécies de aves. As aves consideradas como potencialmente dispersoras de N. megapotamica foram Turdus albicollis Vieillot, 1818, T. rufiventris Vieillot, 1818, Pitangus sulphuratus (Linnaeus, 1766) e T. amaurochalinus Cabanis, 1850 entre as residentes, e Tyrannus savanna Vieillot, 1808 e Myiodynastes maculatus (Müller, 1766) entre as migratórias. As aves com dieta generalista pareceram favorecer a dispersão de N. megapotamica, pois consumiram os frutos inteiros, realizaram visitas curtas (menos de 3 minutos) e apresentaram maior freqüência de visitação que, por sua vez, está relacionada a uma maior remoção dos frutos. Nectandra megapotamica possui características que a incluem no sistema de dispersão generalista, exceto pelo alto valor nutritivo dos seus frutos.
ABSTRACT
The importance of Lauraceae fruits has been reported on the diet of several birds, mainly from the Ramphastidae, Cotingidae and Trogonidae families. The objectives of this study were to determine which birds consume the fruits of Nectandra megapotamica (Spreng.) Mez (Lauraceae) in a deciduous seasonal forest and, based on the analysis of some of the qualitative and quantitative dispersal components, infer which birds can act as dispersers of the seeds. The study was carried out at the Campo de Instrução de Santa Maria (CISM) (29º43'S, 53º42'W), in the vicinity of Santa Maria, in Rio Grande do Sul State, Brazil. In a total of 70 hours of focal observation, 726 visits of 21 bird species were registered. The birds considered as potential dispersers of N. megapotamica were Turdus albicollis Vieillot, 1818, T. rufiventris Vieillot, 1818, Pitangus sulphuratus (Linnaeus, 1766) and T. amaurochalinus Cabanis, 1850 among the residents, and Tyrannus savanna Vieillot, 1808 and Myiodynastes maculatus (Müller, 1766) among the migratory ones. Generalist birds seemed to enhance the dispersal of N. megapotamica, since they consumed the entire fruits, realized short visits (shorter than 3 minutes) and presented high frequency of visits which, in turn, is related to a higher rate of fruit removal. Nectandra megapotamica shows features that allow it to be included in the generalist dispersal system, except for the high nutritional level of its seeds.
A importância dos frutos de Lauraceae tem sido relatada na dieta de muitas aves, principalmente das famílias Ramphastidae, Cotingidae e Trogonidae. Os objetivos deste estudo foram determinar quais espécies de aves consomem os frutos de Nectandra megapotamica (Spreng.) Mez (Lauraceae) numa área de Floresta Estacional Decidual e, com base na análise de alguns dos componentes qualitativos e quantitativos da dispersão, inferir quais aves podem atuar como dispersores de suas sementes. O estudo foi desenvolvido no Campo de Instrução de Santa Maria (CISM) (29º43'S, 53º42'W), município de Santa Maria, Rio Grande do Sul. Num total de 70 h de observação focal, foram registradas 726 visitas de 21 espécies de aves. As aves consideradas como potencialmente dispersoras de N. megapotamica foram Turdus albicollis Vieillot, 1818, T. rufiventris Vieillot, 1818, Pitangus sulphuratus (Linnaeus, 1766) e T. amaurochalinus Cabanis, 1850 entre as residentes, e Tyrannus savanna Vieillot, 1808 e Myiodynastes maculatus (Müller, 1766) entre as migratórias. As aves com dieta generalista pareceram favorecer a dispersão de N. megapotamica, pois consumiram os frutos inteiros, realizaram visitas curtas (menos de 3 minutos) e apresentaram maior freqüência de visitação que, por sua vez, está relacionada a uma maior remoção dos frutos. Nectandra megapotamica possui características que a incluem no sistema de dispersão generalista, exceto pelo alto valor nutritivo dos seus frutos.