Navegando por Autor "Lanna, Lucas L."
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Item Feeding behavior by hummingbirds (Aves: Trochilidae) in artificial food patches in an Atlantic Forest remnant in southeastern Brazil.(2017) Lanna, Lucas L.; Azevedo, Cristiano Schetini de; Claudino, Ricardo Marcelino; Oliveira, Reisla Silva de; Itabaiana, Yasmine AntoniniDuring flight, hummingbirds achieve the maximum aerobic metabolism rates within vertebrates. To meet such demands, these birds have to take in as much energy as possible, using strategies such as selecting the best food resources and adopting behaviors that allow the greatest energy gains. We tested whether hummingbirds choose sources that have higher sugar concentrations, and investigated their behaviors near and at food resources. The study was conducted at Atlantic forest remnant in Brazil, between June and December 2012. Four patches were provided with artificial feeders, containing sucrose solutions at concentrations of 5%, 15%, 25% and 35% weight/volume. Hummingbird behaviors were recorded using the ad libitum method with continuous recording of behaviors. The following species were observed: the Brazilian ruby Clytolaema rubricauda (Boddaert, 1783), Violet-capped woodnymph Thalurania glaucopis (Gmelin, 1788), Scale-throated hermit Phaethornis eurynome (Lesson, 1832), White-throated hummingbird Leucochloris albicollis (Vieillot, 1818), Versicoloured emerald Amazilia versicolor (Vieillot, 1818), Glittering-bellied emerald Chlorostilbon lucidus (Shaw, 1812) and other Phaethornis spp. C. rubricauda, P. eurynome and Phaethornis spp. visited the 35%-sucrose feeders more often, while the T. glaucopis visited the 25%-sucrose feeders more often. L. albicollis and A. versicolor visited more often solutions with sugar concentration of 15%. C. lucidus visited all patches equally. Three behavioral strategies were observed: 1) C. rubricauda and T. glaucopis exhibited interspecific and intraspecific dominance; 2) the remaining species exhibited subordinance to the dominant hummingbirds, and 3) P. eurynome and Phaethornis spp. adopted a hide-and-wait strategy to the dominant hummingbird species. The frequency of aggressive behaviors was correlated with the time the hummingbird spent feeding, and bird size. Our results showed that hummingbirds can adopt different strategies to enhance food acquisition; that more aggressive species feeding more than less aggressive species; and that the birds, especially if they were dominant species, visited high quality food resources more often.Item Perch usage by hummingbirds in a fragment of Atlantic Forest in Brazil.(2016) Lanna, Lucas L.; Azevedo, Cristiano Schetini de; Claudino, Ricardo Marcelino; Oliveira, Reisla Silva de; Itabaiana, Yasmine AntoniniWe investigated if there are aspects of perches that are more attractive for hummingbirds, such as perch height, diameter, and distance from a food patch. The study was conducted in a fragment of Atlantic Forest of the Itacolomi State Park, in Minas Gerais, Brazil, with artificial feeders simulating a rich food patch. Characteristics of perches used by the recorded hummingbirds, such as height, diameter and distance from the food patch, were measured. From the six hummingbird species recorded visiting the artificial feeders, two preferentially used perches with certain characteristics: Thalurania glaucopis used more perches at a height of 0.51–1.0 m (intermediary high), and Leucochloris albicollis used more perches located 1.1–2.0 m distance from the food patch. T. glaucopis was territorial and defended the food patch; L. albicollis was subordinate and did not defend the food patch. The other species seemed to use perches randomly. Our results suggest that hummingbirds used perches according to their social status. Territorial species use perches primarily as platforms for defense and observation of the territory, as well as places of rest between feeding events; subordinate species use perches mainly as resting places during feeding bouts in the absence of the dominant species.