Nesting behavior of the swallow-tailed hummingbird, Eupetomena macroura (Trochilidae, aves)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The dawn lek of the Swallow-tailed Hummingbird

We studied the lek behavior of the Swallow-tailed Hummingbird (Eupetomena macroura) in an urbanized area in S (a) over tildeo Paulo state, Southeastern Brazil. During the 22-month study we identified a total of 26 lekking territories in one lek that covered an area of approximately 12 ha. The lek was active throughout the year; the number of singing males per morning ranged from 6-15. The abandonment of territories and the establishment of new ones caused continuous rearrangement of lek boundaries. Lekking territories had a mean size of 217 m(2) and were separated from each other by 24-120 m. on average, males started singing 27 min before sunrise and kept singing for 17 min. At the end of this period and after a few minutes of silent perching, they abandoned their lekking territories until the next morning. During the singing period. males spent 72-100% of the time inside their territories. The lek behavior of E. macroura is unusual compared to other lekking hummingbirds because of the short daily period of lekking, restricted to just before Sunrise. Since males and females of E. macroura possibly defend feeding territories throughout the rest of the day, the short lekking period may represent a tradeoff between two different time budget pressures from lekking and feeding activities.

Functional aspects of floral nectar secretion of Ananas ananassoides, an ornithophilous bromeliad from the Brazilian savanna

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Behavior at a nest of Amazilia lactea (Aves, Trochilidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Phoretic dispersal on bumblebees by bromeliad flower mites (Mesostigmata, Melicharidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Polinização entomófila em pessegueiro (Prunus persica L.)

Este experimento, realizado na região de Jaboticabal (SP), utilizou uma cultura de pêssego (Prunus persica L.), durante a sua florada com a finalidade de verificar a atuação dos insetos visitantes nas flores na produção de frutos. A concentração média de açucares no néctar e a quantidade média produzida por dia de néctar é de 27,9% e de 3,2 mg, respectivamente. O peso médio das anteras por flor foi de 1,59 mg. A abelha Apis mellifera (73%) foi o principal inseto visitante seguida da Trigona spinipes (17%) e Xylocopa sp (4%). Observou-se a presença de beija-flores (6%), coletando néctar. A freqüência máxima das abelhas A. mellifera, para coleta de néctar e pólen, ocorreu as 12 horas. O número de frutos resultantes do tratamento em que as flores recebiam as visitas foi 14% maior que no tratamento em as flores não eram visitadas. do total de frutos colhidos no tratamento coberto (sem visitas), 82% apresentaram-se perfeitos, com boa formação e simetria. No tratamento descoberto, 90,2% apresentaram-se com boa formação, havendo diferença estatística entre os dois tratamentos.

Band sizes of southeastern Brazilian hummingbirds

Aluminum numbered bands have been used to mark Brazilian hummingbirds since 1993 to obtain biological data as well as ascertain movements and longevities. Bands should be made as narrow as possible by cutting close to the numbers because of the short length of the hummingbird tarsus. Different band lengths should be determined for different species.

Torpor in three species of Brazilian hummingbirds under semi-natural conditions

We measured body temperatures in three species of Brazilian hummingbirds, the Versicolored Emerald (Amazilia versicolor; body mass 4.1 g), the Black Jacobin (Me lantrochilus fuscus; body mass 7.7 g) and the Swallow-tailed Hummingbird (Eupetomena macroura; body mass 8.6 g), during overnight exposure to natural conditions of photoperiod and ambient temperatures. All three species entered torpor. In both A. versicolor and E. macroura, individuals entered torpor even if they had access to feeders up to the time of sunset. In contrast, M. fuscus was less prone to enter torpor and did so mainly if it had been fasting for more than two hours before sunset. Furthermore, M. fuscus often spent the whole night in torpor, whereas the two other species entered torpor for a variable, often short, period of the night. We observed more than one torpor bout during a single night in all three species. We suggest that multiple nocturnal torpors result from interruption of the normal torpor pattern by some (unknown) external stimuli. Any interrupted torpor was always followed by a new entry into torpor, supporting the view that there is a body mass threshold below which the hummingbirds must enter torpor Our data also indicate that these hummingbird species might use torpor even if they are not energetically stressed.

Affinities of the Saw-billed Hermit (Ramphodon naevius) determined by cytochrome-b sequence data

We sequenced 912 bp of the cytochrome-b gene to examine phylogenetic relationships of the enigmatic Saw-billed Hermit (Ramphodon naevius), a large and distinctive hummingbird endemic to tropical forests of southeastern Brazil. Bootstrapped maximum parsimony and maximum likelihood analyses of sequence data from 11 hummingbirds and several outgroups (two swifts, one goatsucker) support: (a) monophyly of the traditional hermit (Phaethornithinae) and nonhermit (Trochilinae) subfamilies, (b) placement of Ramphodon among hermits, and (c) a sister relationship between Ramphodon and an exemplar of the widespread polytypic hermit genus Glaucis. The association of Ramphodon with derived hermit lineages is concordant with subfamilial patterns of wing anatomy and nest architecture. However, the unusual plumages (striped underparts) and male bills (long, serrated, hooked) shared by Ramphodon and the Tooth-billed Hummingbird (Androdon aequatorialis) appear to have evolved within separate hermit and nonhermit tooth-billed clades. Distal placement of the Ramphodon-Glaucis clade within hermits implies that even distinctive Brazilian endemics such as Ramphodon are derived forms that evolved relatively recently.

Partilha de néctar de Eucalyptus spp., territorialidade e hierarquia de dominância em beija-flores (Aves: Trochilidae) no sudeste do Brasil

Territorial behavior in hummingbirds minimizes competition through aggressive interactions, resulting in a dominance hierarchy among species and individuals. Interactions among seven hummingbird species visiting flowering eucalyptus in the Floresta Estadual near Rio Claro, São Paulo, in southeastern Brazil, were studied. Dominance was determined by weight and size with the largest species being the most dominant. Time spent in defense and the number of aggressive interactions were greater than recorded in literature, perhaps due to the relatively greater density of hummingbirds in the study area. Daily activity patterns differed among dominant and subordinate species, but were not correlated with either the quantity of available nectar or with nectar sugar concentration.