CONICET | Buscador de Institutos y Recursos Humanos

We studied the feeding biology of the Dark-Billed Cuckoo (Coccyzus melacoryphus), a summer resident in the Paraná River floodplain. The trophic spectrum, circadian rhythm of feeding activity, food selection, feeding efficiency, prey size and habitat selection are provided. Thirty five stomachs were flushed and their contents identified and quantified to different taxonomic levels. The spectrum was constituted by 19 taxonomic entities, of which one was vegetal. The values obtained by the relative importance index applied were: seed = 3723, Lepidoptera = 3648, Coleoptera = 972, Orthoptera = 946 y Hemiptera = 510. The overall trophic diversity was 1.85. The value of the correlation obtained was not significant, rs = 0.29 and feeding efficiency was 99.36. The circadian rhythm of feeding activity had it´s highest activity at midday. The habitat preference index was applied only at gallery forest and woodland obtaining a value of high selection for both, the gallery forest (0.5) and woodland (0.46). Prey size ranged from 3 to 40 mm, being more frequent in the 0-10 mm interval class, in reference to seeds, and in the 30-40 mm class that correspond to the burning bug (Hylesia nigricans) larvae. According to the obtained results we can conclude that the Dark-Billed Cuckoo is a summer resident with an omnivore diet and wide trophic spectrum, with a restricted area correspond to the gallery forest and woodland.