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 Approximately 20% of the Brazilian Amazon has now been deforested, and is currently experiencing highest rates deforestation in a decade, leading to large‐scale land‐use changes. Roads have consistently implicated as drivers ongoing may act corridors facilitate species invasions. Long‐term data, however, are necessary determine how ecological succession alters avian communities following whether established roads lead constant influx new species. We used data across nearly 40 years...

Abstract Loss of primary rainforest imperils species, communities, and ecosystem services. Secondary forests play a role in supporting forest making it important to assess how variation landscape composition, sample area, secondary age influence their value for maintaining biodiversity. We sampled bird communities three 16‐ha sites 31‐36‐year‐old (SF) adjacent (PF) at the Biological Dynamics Forest Fragments Project near Manaus, Brazil. SF were surrounded by vast, minimally broken PF....

Abstract The value of secondary forest for rain species remains an important question conservation in the 21st century. Here, we describe spatial behavior understory mixed‐species flocks a heterogeneous landscape central Amazonia. Understory represent diverse, highly organized component rich Amazonian avifauna. We recorded movements within 26 flock home ranges primary forest, interfaces between types, and fragments. frequency movement orientation relation to edges, patterns proportion use...

Although species lists from throughout Amazonia have become available, relatively complete inventories based on longterm work remain rare. Longitudinal comparisons at well-studied sites provide the best opportunities for describing communities and identifying changes in regional avifaunas. Within central Amazonia, no region has received as much consistent ornithological coverage terra firme forests north of Manaus, Brazil, Biological Dynamics Forest Fragments Project (BDFFP). Here we an...

Recent long-term studies in protected areas have revealed the loss of biodiversity, yet ramifications for ecosystem health and resilience remain unknown. Here, we investigate how understory birds, lowest stratum forest, affects avian biomass functional diversity Amazon rainforest. Across approximately 30 years Biological Dynamics Forest Fragments Project, used a historical baseline communities to contrast today's primary forest with those modern disturbed habitat. We found that rainforest,...

Proposed mechanisms for the decline of terrestrial and understory insectivorous birds in tropics include a related subset that together has been termed ‘microclimate hypothesis’. One prediction from this hypothesis is sensitivity to bright light environments discourages dimly lit rainforest interior using edges, gaps, or disturbed forest. Using hierarchical Bayesian framework capture data across time space, we tested by first determining vulnerability based on differences within‐species...

The climate variability hypothesis posits that an organism's exposure to temperature determines the breadth of its thermal tolerance and has become important framework for understanding variation in species' susceptibilities change. For example, ectotherms from more thermally stable environments tend have narrower tolerances greater sensitivity projected warming. Among endotherms, however, relationship between physiology is less clear, particularly with regard microclimate...

The Kangean islands are a biologically poorly known archipelago situated in the Java Sea, Indonesia, approximately 120 km directly north of Bali. These host an avifauna comprising at least 13 endemic subspecies, two which have by some sources recently been considered species. We combine historical published literature with our own surveys 2007–2008, 2010 and 2023 to produce complete list islands’ birds (n=140 species) their distribution across islands. evaluate more detail conservation...

Abstract ∙ The Variegated Antpitta (Grallaria varia) is the largest member of terrestrial insectivores guild within its Amazonian range. Despite bird’s large size and loud vocalizations, however, basic aspects G. varia’s natural history remain poorly understood. In this study, we conducted intensive tracking one individual in a nature reserve state Amazonas, Brazil, describing ‐ for first time with radio telemetry space use, movement patterns, roosting sites varia. Over course 50 days July...

Although the duration of biological rhythms varies from milliseconds to decades, daily cycles are especially widespread for individual organisms. These circadian synchronized by light–dark cycles, which govern predictable changes in other microclimate variables. Despite fixed, regular nature these abiotic at low latitudes, little is known about how different animals structure activity along gradients. We used 25 years capture–recapture data and ~ 000 unique captures characterize ‘activity'...

Abstract How species interact with human‐disturbed environments is a central focus of conservation biology. Within disturbed landscapes, regenerating forests have potential to provide habitat for forest species, especially as increasing amounts primary are lost. As secondary regenerates beside forest, it increases heterogeneity. However, relatively little known about the influence heterogeneity on space use. In this study, we analyzed topography and vertical vegetation structure small...

Although lowland tropical rain forests were once widely believed to be the archetype of stability, seasonal variation exists. In these environments, seasonality is defined by rainfall, leading a predictable pattern biotic and abiotic changes. Only full annual cycle reveals niche breadth, yet most studies organisms ignore seasonality, thereby underestimating realized conditions. If human-modified habitats display more stress than intact habitats, then ignoring will have particularly important...

Abstract Twenty percent of the Brazilian Amazon has now been deforested, and deforestation rates are increasing. This compels us to evaluate conservation potential human-modified landscapes; yet ecological value regenerating fragmented Amazonian forests remains poorly understood. To date, most faunal studies in disturbed have examined metrics derived from presence or abundance. Although valuable, these data cannot tell how old-growth species using forests. In this study, we complement with...

Isthmohyla picadoi is a Neotropical hylid frog found in upper humid montane forests of Costa Rica and Panama. The species particular interest because it continues to persist an area which the amphibian community has otherwise been decimated by pathogenic fungus, Batrachochytrium dendrobatidis. Ground search, ladder climbing, tree climbing techniques were used locate 32 individuals; including adult males females, juveniles, metamorphosing frogs. majority frogs bromeliads, although some...

Abstract Aim One of the oldest and most powerful ways for ecologists to explain distinct biological communities is invoke underlying environmental differences. But in hyper‐diverse systems, which often display high species richness low abundance, these sorts community comparisons are especially challenging. The classic view Amazonian birds posits that riverine barriers habitat specialization determine local regional composition. We test tacit, complementary assumption similar bird should...

Abstract Woodcreepers (Dendrocolaptinae) represent a remarkably uniform group of brownish birds that move by hitching up tree trunks as they forage for arthropod prey. Despite these superficial similarities, we were able to uniquely differentiate the niches all 13 species north Manaus integrating morphological traits (e.g., mass and bill size) with behavioral sociality, stratum use, foraging maneuvers). The 5 ant-following (myrmecophilous) species, their larger bodies heavier bills,...

Orange-fronted Plushcrown Metopothrix aurantiaca is a unique, but easily overlooked, small furnariid found in the midstorey and canopy of riverine areas Amazon. The species' previously published distribution includes parts southernmost Colombia, eastern Ecuador, Peru, northern Bolivia western Brazil. In easternmost part its (Brazil), M. occurs states Acre, Amazonas Rondônia, east to 64°W. We present nine new records species Brazil, all them known together extending range by c.750 km. These...

Abstract Rainforest loss threatens terrestrial insectivorous birds throughout the world’s tropics. Recent evidence shows these to be declining in undisturbed Amazonian rainforest, possibly due climate change. Here, we first addressed whether insectivores were exposed change using 38 years of data. We found that has changed central Amazonia, especially dry season, which was ∼1.3°C hotter and 21% drier 2019 than 1981. Second, test actively avoided hot conditions, used field sensors identify...