Riqueza y características morfométricas de aves de sotobosque en Varillal Alto Seco de la Reserva Nacional Allpahuayo Mishana, Perú

Se evaluaron las aves de sotobosque en el Varillal Alto Seco de la Reserva Nacional Allpahuayo Mishana (RNAM) entre enero y mayo de 2016 para determinar su riqueza y características morfométricas mediante conteo por puntos aplicando observación directa, reconocimiento auditivo y captura con redes de neblina. Se registró una riqueza de 12 órdenes, 18 familias y 122 especies, donde el orden de Passeriformes registró 13 familias y Thamnophilidae con 23 especies. La riqueza de especies entre varillales varió entre 85 especies (varillal B) y 51 especies (varillal C). Los índices no paramétricos indican que la riqueza específica de aves observadas (122 especies) siempre estuvo por debajo de lo esperado (CHao 1 con 130 especies; CHao 2 con 133 especies; Bootstrap con 136 especies y Jackknife 1 con 149 especies) y la misma tendencia se observó con la curva de Clench con 166 especies esperadas, mientras que los índices de diversidad de Simpson variaron entre 0.96 y 0.98, Shannon-Winner entre 3.69 y 4.30 y Margalef entre 10.31 y 16.93, indicando una alta diversidad de aves. Los datos morfométricos de las especies capturadas muestran baja variabilidad con respecto a lo reportado para otros lugares, excepto Geootrygon montana, Celeus elegans, Pithys albifrons, Schistocicla leucostigma, Xiphorhynchus elegans, Attila spadiceus y Manacus manacus que presentan una mayor variabilidad. Se concluye que el sotobosque del Varillal Alto tiene una riqueza de aves alta en la RNAM.

Structure of Lekking Courts of Male White-Bearded Manakins (Manacus Manacus) Is Linked to Their Attractiveness

Male White-bearded Manakins (Manacus manacus) perform courtship displays on individual courts in close proximity of each other, while females visit them to choose potential mates. These displays represent a sequence of physiologically demanding movements, including rapid hops between saplings on the court. Our observations of courtship behavior and court characteristics of eight males suggest that the structure of the court may be an important factor in courtship: we found regularities in the inter-sapling distances on the courts of males that attracted females. We hypothesize that sexual selection by females may favor those males that have courts providing an optimal platform for their courtship display.Estructura de escenarios de lek de saltarines barbiblancos (Manacus manacus) es conectada a su atractivoResumen: Los saltarines barbiblancos (Manacus manacus) machos realizan despliegues de cortejo en “escenarios” individuales cercanos los unos a los otros, mientras las hembras los visitan para escoger su pareja potencial. Estos despliegues representan una secuencia de movimientos fisiológicamente arduos, que incluyen saltos rápidos entre los palos o plantones del escenario. Nuestras observaciones de comportamiento nupcial y de las características de los escenarios de ocho machos sugieren que la estructura del escenario puede ser importante para cortejo: habían regularidades en distancias entre los palos de los escenarios de los machos que atrajeron hembras. Formulamos la hipótesis que la selección sexual realizada por las hembras favorece los machos con escenarios que proporcionan una plataforma óptima para sus despliegues de cortejo.

Seed dispersal by the lek-forming white-bearded manakin (Manacus manacus, Pipridae) in the Brazilian Atlantic forest

The movement patterns of males, females and juveniles of lekking species often differ due to differences in the commitment to lek activities, which may lead to differences in the spatial distribution and dispersal distances of seeds they eat. By sampling seeds in three lek and non-lek areas of the white-bearded manakin (Manacus manacus), we tested whether this lekking species increased the abundance and species richness of seeds in lek areas and, at a finer scale, in 21 displaying courts within lek areas. Combining data on seed defecation or regurgitation rates by free-ranging individuals, the number of seeds in droppings or regurgitations of mist-netted birds, and the distances travelled by birds equipped with radio-transmitters, we estimated the potential spatial distribution of seeds generated by six resident males and six females or juveniles during the morning peak of lek activity and when lek activity decreased in the afternoon. There was no difference in the species richness (46 and 44 morphospecies, respectively) and abundance of seeds (15.4 ± 7.3 seeds and 14.0 ± 1.1 seeds, respectively) between lek and non-lek areas. Within leks both parameters increased in courts (45 spp., 17.6 ± 14 seeds) compared with non-court sites (22 spp., 1.9 ± 1.8 seeds), likely as a consequence of the longer time spent by resident males in perches in or near display courts. Distances moved by juveniles and females per 60-min period (183 ± 272 m) were greater than resident males (42.6 ± 22.0 m) in the mornings, while the opposite happened in the afternoons (55.2 ± 40.7 m and 157 ± 105 m, respectively). We conclude that the spatial aggregation of seeds in lek areas of M. manacus occurs at the court level, and the spatial distribution of deposited seeds varies with manakin lekking status and the daily period of foraging.

Frugivory by the White-bearded Manakin (Manacus manacus, Pipridae) in restinga forest, an ecosystem associated to the Atlantic forest

Manakins (Pipridae) are one of the most abundant fruit-eaters and seed dispersers in the understory of neotropical forests. We describe the fruit diet of the White-beaded Manakin (Manacus manacus) based on a two-year study of its foraging behavior on fruiting plants, collecting seeds from feces and regurgitations of trapped individuals, and from lekking males' courts in restinga forests at the southern coast of the state of São Paulo, Brazil. Manacus manacus consumed 58 species of fruits from 30 different plant families. Fruits were taken at 3.5 ± 1.9 m height and 1.5 ± 1.6 m below the forest canopy using mainly sally-strike and glean manoeuvres. Most of the fruits were berries ranging from 3.1 to 17 mm in diameter and containing from 1 to 86 seeds. Fruits up to 12 mm in diameter were swallowed whole. Ripe and unripe fruits were equally consumed. Our results corroborate with the great variety of small fruits consumed by manakin species, and indicate that M. manacus is an important seed disperser, potentially contributing to recruitment of plants in restinga.