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Vocal behavior in tropical hummingbirds is a new area of study. Here, we present findings on the vocalizations and associated behaviors of two species: Sombre Hummingbird (Aphantochroa cirrhochloris) and Rufous-breasted Hermit (Glaucis hirsutus). These are the only hummingbirds in which the brain areas activated by singing have been demonstrated. They are also among the basal species of their respective subfamilies, Trochilinae and Phaethornithinae and, thus, represent early stages in the evolution of hummingbird vocal communication. We found that the two species exhibit distinctive vocalizations and behaviors. Sombre Hummingbird calls had more modulation and were often used during agonistic interactions, whereas Rufous-breasted Hermit calls had higher pitch and purer tones and were produced in less aggressive interactions. Sombre Hummingbird song was highly stereotyped in syllable structure and syntax, whereas Rufous-breasted Hermit song was highly variable. Comparative analysis points to consistent similarities in use of vocalizations by the Sombre Hummingbird and other trochilines, and by the Rufous-breasted Hermit and other phaethornithines. We hypothesize that differences in vocal behavior between hummingbird lineages arise as adaptations to their foraging strategies. Key words: Aphantochroa cirrhochloris, Glaucis hirsutus, Rufous-breasted Hermit, Sombre Hummingbird, syntax, territorial, vocal learners. El comportamiento vocal de los picaflores tropicales es un area de estudio nueva. Aqui presentamos los hallazgos sobre las vocalizaciones y los comportamientos asociados de dos especies: Aphantochroa cirrhochloris y Glaucis hirsutus. Estos son los unicos picaflores en los que se ha demostrado que algunas areas del cerebro se activan con el canto. Ellos estan tambien entre las especies basales de sus respectivas subfamilias, Trochilinae y Phaethornithinae y, por ende, representan estados tempranos en la evolucion de la comunicacion vocal de los picaflores. Encontramos que las dos especies exhiben vocalizaciones y comportamientos distintivos. Las llamadas de Aphantochroa cirrhochloris presentaron mas modulaciones y fueron usualmente empleadas durante interacciones agonisticas, mientras que las llamadas de G. hirsutus presentaron frecuencias mas altas y tonos mas puros y fueron producidas durante interacciones menos agresivas. El canto de Aphantochroa cirrhochloris fue muy estereotipado en la estructura de silabas y en la sintaxis, mientras que el canto de G. hirsutus fue muy variable. Los analisis comparativos senalan similitudes consistentes en el uso de las vocalizaciones por parte de A. cirrhochloris y otros Trochilinae, y de G. hirsulus y otros Phaethornithinae. Hipotetizamos que las diferencias en el comportamiento vocal entre los linajes de picaflores aparecen como adaptaciones a sus estrategias de forrajeo.

Serial induction of stimuli in the fingers changes the neuronal specificity and somatosensory maps of the hand surface in adult owl monkey, trained to respond to particular stimulus sequence events. Synchronous application of remodelling stimuli to the fingers causes their integration whereas, asynchronous induction of stimuli causes their segregation. A terminal electrophysiological neuronal response mapping analysis reveals that conditioned monkeys have multiple-digit receptive fields.