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The goal of this study is to provide a taphonomic analysis of bone fragments found in harpy eagle nests in the Brazilian Amazonia, utilizing the largest sample of prey remains collected to date. Harpy eagle kill samples were collected from nine nests, between June 2016 and December 2020 in Mato Grosso, Brazil. We identified the specimens, calculated the number of identified specimens (NISP) and minimum number of individuals (MNI). These metrics were used to estimate bone survivability and fragmentation. A total of 1661 specimens (NISP) were collected, representing a minimum number of 234 individuals (MNI). We identified at least nine species of primates, which represent 63.8% of the individuals in the kill sample. Harpy eagles preyed mostly on the medium‐sized capuchin and bearded saki monkeys (28.2% of the MNI), and two‐toed sloths (17.7% of the MNI). The large woolly monkeys also represented a significant portion of the sample (11.5% of the MNI). Three distinct patterns of bone survivability were found, one characterizing two‐toed sloths, another characterizing medium‐sized monkeys, and a third typical of woolly monkeys. We conclude that harpy eagle predation leaves an identifiable signature on the prey with a bone survivability pattern specific to each taxon. The intertaxon variations observed in the taphonomic signatures of harpy eagle kills should be taken into account when evaluating the potential influence of these raptors as accumulators of bone material in both paleontological and neontological assemblages. Research highlights: Harpy eagles are major accumulators of primate bones.Harpy eagle prey remains can be distinguished from those of other accumulators.Bone survivability shows three distinct patterns depending on the prey species.Taphonomic signature of harpy eagle prey remains are similar to other large raptors that consume primates. [ABSTRACT FROM AUTHOR]

Quantifying resource partitioning between co‐occurring species can provide insight into processes facilitating coexistence by closely related species, a fundamental question in ecology. We tested whether the habitat requirements of two closely related Neotropical forest eagles, the Crested Eagle Morphnus guianensis and Harpy Eagle Harpia harpyja, differ at fine and coarse resolutions across their shared geographical range. Using landcover and topographical covariates, we quantified potential resource overlap first using higher resolution (30 arc‐s, ~ 1‐km2 data) generalized linear models (GLMs), and secondly using coarser‐grain (2.5 arc‐min, ~ 4.5‐km2 data) environmental ordination to capture the potential effect of scale on habitat overlap. The distribution of both eagles was largely explained by canopy tree species richness and canopy structural complexity, with peak suitability of 60–80% evergreen forest cover. Both eagles were negatively associated with mosaic forest and cultivated areas. From the GLMs, habitat overlap was >93% in geographical space but was reduced to 73% when considering environmental space, a proxy for resource overlap. From ordination (principal component analysis), resource overlap was 67% in environmental space, with randomization tests supporting equivalent environmental space for both eagles. Our results suggest that at the continental scale, Crested and Harpy Eagles share identical environmental space when quantified at fine and broad scales, with little difference in distribution and habitat use. At the continental scale used here, both eagles can coexist, presumably with sufficient habitat heterogeneity for coexistence when they occur in close proximity. Therefore, further research is required at the local level to capture fully where coexistence at the local scale is facilitated more by fine‐scale habitat selection, or difference in diet between two species with indistinguishable habitat use. [ABSTRACT FROM AUTHOR]

Aim: A current biogeographic paradigm states that climate regulates species distributions at continental scales and that biotic interactions are undetectable at coarse‐grain extents. However, advances in spatial modelling show that incorporating food resource distributions are important for improving model predictions at large distribution scales. This is particularly relevant to understand the factors limiting the distribution of widespread apex predators whose diets are likely to vary across their range. Location: Neotropical Central and South America. Methods: The harpy eagle (Harpia harpyja) is a large raptor, whose diet is largely comprised of arboreal mammals, all with broad distributions across Neotropical lowland forest. Here, we used a hierarchical modelling approach to determine the relative importance of abiotic factors and prey resource distribution on harpy eagle range limits. Our hierarchical approach consisted of the following modelling sequence of explanatory variables: (a) abiotic covariates, (b) prey resource distributions predicted by an equivalent modelling for each prey, (c) the combination of (a) and (b), and (d) as in (c) but with prey resources considered as a single prediction equivalent to prey species richness. Results: Incorporating prey distributions improved model predictions but using solely biotic covariates still resulted in a high‐performing model. In the Abiotic model, Climatic Moisture Index (CMI) was the most important predictor, contributing 76% to model prediction. Three‐toed sloth (Bradypus spp.) was the most important prey resource, contributing 64% in a combined Abiotic‐Biotic model, followed by CMI contributing 30%. Harpy eagle distribution had high environmental overlap across all individual prey distributions, with highest coincidence through Central America, eastern Colombia, and across the Guiana Shield into northern Amazonia. Main Conclusions: With strong reliance on prey distributions across its range, harpy eagle conservation programmes must therefore consider its most important food resources as a key element in the protection of this threatened raptor. [ABSTRACT FROM AUTHOR]

Climate change is expected to have a profound impact on species distributions, contracting suitable climate space. Biodiversity areas are important to mitigate these negative effects but are static by design and thus do not account for future projections of species distributions. The Harpy Eagle Harpia harpyja has a broad range across lowland Neotropical forests and thus its distribution could be negatively affected by climate change when combined with current rates of habitat loss. To test this hypothesis, we use spatial point process models fitted with climatic, topographical and landcover covariates to identify the current distribution. We then project to 24 future climate scenarios, using three General Circulation Models (GCMs) and two emission scenarios between the years 2021 and 2100 averaged over four, 20‐year periods. Our current model identified a core range across Amazonia and the Guiana Shield, with evergreen forest (71%), mean diurnal temperature range (13%) and elevation (6%) the most important predictors. Reclassifying the current model to a binary prediction estimated a range size of ~ 7.6 million km2, with the Important Bird and Biodiversity Area (IBA) network covering 18% of habitat (~ 1.4 million km2) within this range. By 2090, range size was predicted to decrease on average by 14.4% under a higher emissions scenario, and 7.3% under a lower emissions scenario. The IBA network would cover 14% less area under a higher emissions scenario, and 3.3% less distribution area under a lower emissions scenario by 2090. Southern Amazonia is predicted to have the greatest reduction in range size and subsequently highest loss of Harpy Eagle habitat within the IBA network. Our work demonstrates that the combination of climate change and subsequent habitat loss may result in substantial losses in distribution for this raptor across the southern edge of its range. [ABSTRACT FROM AUTHOR]

Understanding species–environment relationships is key to defining the spatial structure of species distributions and develop effective conservation plans. However, for many species, this baseline information does not exist. With reliable presence data, spatial models that predict geographic ranges and identify environmental processes regulating distribution are a cost‐effective and rapid method to achieve this. Yet these spatial models are lacking for many rare and threatened species, particularly in tropical regions. The harpy eagle (Harpia harpyja) is a Neotropical forest raptor of conservation concern with a continental distribution across lowland tropical forests in Central and South America. Currently, the harpy eagle faces threats from habitat loss and persecution and is categorized as Near‐Threatened by the International Union for the Conservation of Nature (IUCN). Within a point process modeling (PPM) framework, we use presence‐only occurrences with climatic and topographical predictors to estimate current and past distributions and define environmental requirements using Ecological Niche Factor Analysis. The current PPM prediction had high calibration accuracy (Continuous Boyce Index = 0.838) and was robust to null expectations (pROC ratio = 1.407). Three predictors contributed 96% to the PPM prediction, with Climatic Moisture Index the most important (72.1%), followed by minimum temperature of the warmest month (15.6%) and Terrain Roughness Index (8.3%). Assessing distribution in environmental space confirmed the same predictors explaining distribution, along with precipitation in the wettest month. Our reclassified binary model estimated a current range size 11% smaller than the current IUCN range polygon. Paleoclimatic projections combined with the current model predicted stable climatic refugia in the central Amazon, Guyana, eastern Colombia, and Panama. We propose a data‐driven geographic range to complement the current IUCN range estimate and that despite its continental distribution, this tropical forest raptor is highly specialized to specific environmental requirements. [ABSTRACT FROM AUTHOR]