Neotropical mixed-species bird flocks in a community context.

Mixed-species flocks are an important component of bird communities, particularly in the Neotropics, where flocks reach their highest diversity. The extent to which mixed-species flocks represent unique functional or ecological roles within communities, and how these attributes change over environmental gradients, however, is not well understood. We use a trait-based approach to examine functional aspects of flocking assemblages as they relate to those observed in the larger avian community across a 3000 m elevational gradient.

Floral phenology of an Andean bellflower and pollination by buff-tailed sicklebill hummingbird.

The Andean bellflowers comprise an explosive radiation correlated with shifts to specialized pollination. One diverse clade has evolved with extremely curved floral tubes and is predicted to be pollinated exclusively by one of two parapatric species of sicklebill hummingbirds (). In this study, we focused on the floral biology of , a bellflower thought to be specialized for pollination by , in a montane cloud forest site in southeastern Peru.

Plant-Pollinator Specialization: Origin and Measurement of Curvature.

AbstractA feature of biodiversity is the abundance of curves displayed by organs and organisms. Curvature is a widespread, convergent trait that has important ecological and evolutionary implications. In pollination ecology, the curvature of flowers and pollinator mouthparts (e.

A meta-analysis of global avian survival across species and latitude.

Tropical birds are purported to be longer lived than their temperate counterparts, but it has not been shown whether avian survival rates covary with latitude worldwide. Here, we perform a global-scale meta-analysis of 949 estimates from 204 studies of avian survival and demonstrate that a latitudinal survival gradient exists in the northern hemisphere, is dampened or absent for southern hemisphere species, and that differences between passerines and nonpasserines largely drive these trends. We also show that while extrinsic factors related to climate were poor predictors of apparent survival compared to latitude alone, the relationship between apparent survival and latitude is strongly mediated by intrinsic traits - large-bodied species and species with smaller clutch size had the highest apparent survival.

Composition and distribution of lice (Insecta: Phthiraptera) on Colombian and Peruvian birds: New data on louse-host association in the Neotropics.

The diversity of permanent ectoparasites is likely underestimated due to the difficulty of collecting samples. Lice (Insecta: Phthiraptera) are permanent ectoparasites of birds and mammals; there are approximately 5,000 species described and many more undescribed, particularly in the Neotropics. We document the louse genera collected from birds sampled in Peru (2006-2007) and Colombia (2009-2016), from 22 localities across a variety of ecosystems, ranging from lowland tropical forest and Llanos to high elevation cloud forest.

The Manú Gradient as a study system for bird pollination.

Background: This study establishes an altiudinal gradient, spanning from the highland Andes (2400 m) to lowland Amazon, as a productive region for the study of bird pollination in Southeastern Peru. The 'Manú Gradient' has a rich history of ornithological research, the published data and resources from which lay the groundwork for analyses of plant-bird interactions. In this preliminary expedition we documented 44 plants exhibting aspects of the bird pollination syndrome, and made field observations of hummingbird visits at three sites spanning the Manú Gradient: 2800 m (Wayqecha), 1400 m (San Pedro), and 400 m (Pantiacolla).

Squeezed at the top: Interspecific aggression may constrain elevational ranges in tropical birds.

Tropical montane species are characterized by narrow elevational distributions. Recent perspectives on mechanisms maintaining these restricted distributions have emphasized abiotic processes, but biotic processes may also play a role in their establishment or maintenance. One historically popular hypothesis, especially for birds, is that interspecific competition constrains ranges of closely related species that "replace" each other along elevational gradients.

Urban mockingbirds quickly learn to identify individual humans.

Practically all animals are affected by humans, especially in urban areas. Although most species respond negatively to urbanization, some thrive in human-dominated settings. A central question in urban ecology is why some species adapt well to the presence of humans and others do not.

Beta diversity along environmental gradients: implications of habitat specialization in tropical montane landscapes.

1. Understanding how species in a diverse regional pool are spatially distributed with respect to habitat types is a longstanding problem in ecology. Tropical species are expected to be specialists along environmental gradients, and this should result in rapid compositional change (high beta diversity) across landscapes, particularly when alpha diversity is a small fraction of regional diversity.