Abstract How are rainforest birds faring in the Anthropocene? We use bird captures spanning > 35 years from 55 sites within a vast area of intact Amazonian to reveal reduced abundance terrestrial and near‐ground insectivores absence deforestation, edge effects or other direct anthropogenic landscape change. Because undisturbed forest includes far fewer than it did historically, today’s fragments second growth more impoverished shown by comparisons with modern ‘control’ sites. Any goals...

Warming from climate change is expected to reduce body size of endotherms, but studies temperate systems have produced equivocal results. Over four decades, we collected morphometric data on a nonmigratory understory bird community within Amazonian primary rainforest that experiencing increasingly extreme climate. All 77 species showed lower mean mass since the early 1980s—nearly half with 95% confidence. A third concomitantly increased wing length, driving decrease in mass:wing ratio for...

ABSTRACT Accurately differentiating age classes is essential for the long-term monitoring of resident New World tropical bird species. Molt and plumage criteria have long been used to accurately temperate birds, but application age-classification models Neotropics has hindered because annual life-cycle events birds do not always correspond with nomenclature. However, recent studies shown that similar molt can be categorize into classes. We propose a categorical system based on identification...

Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying ecological affected by modification they provide metrics that quantify structure and function. Here, we examine large-scale alteration has among mixed-species flocking birds Amazonian rainforest....

Abstract Forests are being converted to agriculture throughout the Afrotropics, driving declines in sensitive rainforest taxa such as understorey birds. The ongoing expansion of cocoa agriculture, a common small‐scale farming commodity, has contributed loss 80% cover some African countries. farms may provide habitat for biodiversity, yet little is known about their suitability vertebrate fauna, or effect farm management on animal communities. Here, we report first in‐depth investigation into...

Stable understory microclimates within undisturbed rainforests are often considered refugia against climate change. However, this assumption contrasts with emerging evidence of Neotropical bird population declines in intact rainforests. We assessed the vulnerability resident rainforest birds to climatic variability, focusing on dry season severity characterized by hotter temperatures and reduced rainfall. Analyzing 4264 individual captures over 27 years, we found that harsher Amazonian...

The Congo Basin rainforest and adjacent Lower Guinea Forest constitute the second largest tract of lowland tropical in world. As with rest continent, human population is increasing rapidly forest degradation ubiquitous. through logging has pervasive negative effects on ecosystems, but selective considered less impactful than clearcutting. Recent research Afrotropical shows that certain avian species guilds are more affected by others (e.g., specialist insectivores such as followers Dorylus...

Avian diversity in fragmented Amazonian landscapes depends on a balance between extinction and colonization cleared disturbed areas. Regenerating forest facilitates bird dispersal within degraded may tip the favor of persistence habitat patches. Determining response birds to fragmentation be hindered because many species use adjacent second growth matrices thereby limiting applicability island biogeography predict loss; alternatively, countryside biogeographic framework evaluate value...

Nearctic-neotropic migrant birds need to replenish energy reserves during stopover periods successfully complete their semiannual movements. In this study we used linear models examine the habitat use of 11 species in northeastern Costa Rica better understand influence food and structural resources on presence periods. Our indicated that frugivorous migrants primarily abundance, while insectivorous chiefly vegetation structure as cues for stopover. addition models, documented fruiting plant...

We assessed the occupancy dynamics of 275 California Spotted Owl (Strix occidentalis occidentalis) territories in 4 study areas Sierra Nevada, California, USA, from 1993 to 2011. used Landsat data develop maps canopy cover for each area, which we then quantify annual territory-specific habitat covariates. modeled relationships between territory extinction and colonization using predictor variables habitat, disturbance (logging, fire), climate, elevation. found that forests with medium...

Habitat destruction and degradation are the leading causes of species declines extinctions in world. Human altered landscapes often leave fragments previously continuous habitat, which may be significant conservation value. We assessed effects habitat fragmentation on taxonomic diversity, community composition, nestedness avian communities before after fragment isolation at Biological Dynamics Forest Fragments Project research site Amazon rainforest. Species loss 10ha 100ha was significantly...

Patterns of habitat use directly influence a species' fitness, yet for many species an individual's age can patterns use. However, in tropical rainforests, which host the greatest terrestrial diversity, little is known about how classes different adjacent habitats varying quality. We long-term mist net data from Amazon rainforest to assess among adult, adolescent (teenage) and young understory birds forest fragments, primary secondary at Biological Dynamics Forest Fragments Project Brazil....

Detailed accounts of molt and breeding cycles remain elusive for the majority resident tropical bird species. We used data derived from a museum review 12 years banding to infer seasonality, patterns, age gender criteria 27 common landbird species in northeastern Costa Rica. Prealternate molts appear be rare, only occurring one (Sporophila corvina), while presupplemental were not detected. Most our study (70%) symmetrically replace flight feathers during absence migrant birds; molting this...

Abstract Many species of birds show distinctive seasonal breeding and nonbreeding plumages. A number hypotheses have been proposed for the evolution this dichromatism, specifically related to idea that may experience variable levels sexual selection relative natural throughout year. However, these not addressed selective forces shaped molt, underlying mechanism plumage change. Here, we examined relationships between life‐history variation, a dichromatism in New World warblers (Aves:...

Abstract Of the approximately 716 bird species that breed in North America, 386 (54%) are considered Nearctic–Neotropical migrants by U.S. Fish and Wildlife Service. In past 50 yr, scores of these migratory species, including some once common, have declined dramatically. normally spend 6–8 months tropical habitats, making identification, availability, management Neotropical habitats critical issues for their conservation. Yet, most complete nuanced information about use relative effects...

Climatic changes induced by the El Niño—Southern Oscillation (ENSO) commonly influence biological systems; however, climatic variability and multitrophic interactions within tropical latitudes remain poorly understood. We examined relationships between migrant condition ENSO during spring migration in Costa Rica. Our study is based on correlating an index with body-condition metrics of six Nearctic—Neotropic bird species stopover Rica over a 10-year period. This first to report correlations...

Survival estimates of tropical birds have been used to examine life‐history variation across latitudes and dietary guilds. Here, we provide apparent survival 31 rainforest species from central Amazonian Brazil compare our results with Ecuador, Peru (western Amazonia) French Guiana (eastern geographic in demography. Our averaged annual estimate for (ϕ= 0.59, SE = 0.10) was concordant previously published the western Amazon 0.58, 0.02), eastern 0.63, 0.06). Two predominate demographic patterns...

ABSTRACT Barred owls ( Strix varia ) are forest‐dwelling owls, native to eastern North America, with populations that expanded westward into the range of spotted owl occidentalis ). exert an overwhelmingly negative influence on thereby threatening population viability where species co‐occur. In this review, we provide overview barred owl's expansion and detail synthesize previously published literature within as related potential future outcomes for northern S. o. caurina We include research...