Apex predators are threatened globally, and their local extinctions are often driven by failures in sustaining prey acquisition under contexts of severe prey scarcity. The harpy eagle Harpia harpyja is Earth’s largest eagle and the apex aerial predator of Amazonian forests, but no previous study has examined the impact of forest loss on their feeding ecology. We monitored 16 active harpy eagle nests embedded within landscapes that had experienced 0 to 85% of forest loss, and identified 306 captured prey items. Harpy eagles could not switch to open-habitat prey in deforested habitats, and retained a diet based on canopy vertebrates even in deforested landscapes. Feeding rates decreased with forest loss, with three fledged individuals dying of starvation in landscapes that succumbed to 50–70% deforestation. Because landscapes deforested by > 70% supported no nests, and eaglets could not be provisioned to independence within landscapes > 50% forest loss, we established a 50% forest cover threshold for the reproductive viability of harpy eagle pairs. Our scaling-up estimate indicates that 35% of the entire 428,800-km2 Amazonian ‘Arc of Deforestation’ study region cannot support breeding harpy eagle populations. Our results suggest that restoring harpy eagle population viability within highly fragmented forest landscapes critically depends on decisive forest conservation action.

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While taxonomic and biogeographical biases are often acknowledged, those for certain biological responses and species traits are routinely overlooked, generating major gaps in knowledge and conservation of biodiversity. Biases in research on birdsan over-sampled, diverse vertebrate classmay be readily detectable, and wetlands are important species-rich ecosystems in which to identify biases and research gaps for birds. The Pantanal, one of the world's largest wetlands, is globally relevant for bird conservation. In this wetland, we determined spatial, temporal, taxonomic and biological response-related biases in ornithological studies to guide future research in this ecosystem and, ultimately, in major global wetlands. Avian research was geographically biased, with 61 studies conducted in the Brazilian Pantanal and only one in Bolivia. Most studies were concentrated near urban centres, with poorly explored areas in the central Pantanal. Research was also over-represented during the dry season when field conditions are more favourable, but such temporal bias may hamper migration studies. Considering their richness, some families were studied disproportionately more (e.g. Jacanidae) or less (e.g. Tyrannidae). Some species (e.g. Wood Stork Mycteria americana and Yellow-billed Cardinal Paroaria capitata) were included in > 25% of studies, whereas a relatively low number of threatened bird species were studied. Behaviour was the most studied response, followed by abundance and reproduction, which were considered for > 65% of species studied. We conclude that further research needs to be focused on unexplored areas and periods, less detectable species, and ecological processes (e.g. interspecific interactions). Additionally, our results can provide useful information to better address future work and bird conservation actions in other large wetlands. For example, major gaps detected here constitute a primary roadmap to guide research in under-sampled regions, such as the Canadian peatlands and Tonlé Sap Lake. Specifically, more studies on waterbirds in highly diverse wetlands from low-income countries (e.g. Okavango and Sundarban Delta) may help to disentangle the essential functional role provided for these species and to prioritize conservation actions in regions with limited research capacity.

Acoustic communication is particularly important in environments such as dense tropical forests, where the dim light constrains the efficacy of visual signals. In these environments, complex species interactions could promote the evolution of acoustic signals and result in intriguing patterns of mimicry and convergence. In the Neotropical region, Neomorphus ground‐cuckoos frequently associate with herds of collared peccaries and white‐lipped peccaries. Bill clacking behavior in ground‐cuckoos closely resembles the sound of teeth clacking in peccaries and these acoustic signals are used in agonistic and foraging contexts in both species. Here we demonstrate that the acoustic characteristics of bill clacking in ground‐cuckoos are more similar to teeth clacking of peccaries than to bill clacking of the more closely related Geococcyx roadrunner. We propose that two hypotheses may explain the evolution of the clacking behavior in these taxa. First, because peccaries are known to successfully ward off attacks from large predators to defend their herds, mimicking their clacking can deceive predators, either by triggering clacking from nearby peccaries, or making it appear to the predators that peccaries are present when they are not. Second, ground‐cuckoos and peccaries could mutually benefit from the use of similar signals to alert each other of the presence of predators. In this context, ground‐cuckoos could serve as sentinels while peccaries could confer protection. We also discuss alternative explanations for this striking acoustic resemblance. Ground‐cuckoos and peccaries provide an interesting opportunity to study how an ecological association could foster the evolution of acoustic mimicry.

Migratory birds are implicated in dispersing haemosporidian parasites over great geographic distances. However, their role in sharing these vector-transmitted blood parasites with resident avian host species along their migration flyway is not well understood. We studied avian haemosporidian parasites in 10 localities where Chilean Elaenia, a long-distance Neotropical austral migrant species, spends part of its annual cycle to determine local parasite transmission among resident sympatric host species in the elaenia's distributional range across South America. We sampled 371 Chilean Elaenias and 1,818 birds representing 243 additional sympatric species from Brazilian wintering grounds to Argentinian breeding grounds. The 23 haemosporidian lineages found in Chilean Elaenias exhibited considerable variation in distribution, specialization, and turnover across the 10 avian communities in South America. Parasite lineage dissimilarity increased with geographic distance, and infection probability by Parahaemoproteus decreased in localities harbouring a more diverse haemosporidian fauna. Furthermore, blood smears from migrating Chilean Elaenias and local resident avian host species did not contain infective stages of Leucocytozoon, suggesting that transmission did not take place in the Brazilian stopover site. Our analyses confirm that this Neotropical austral migrant connects avian host communities and transports haemosporidian parasites along its distributional range in South America. However, the lack of transmissive stages at stopover site and the infrequent parasite lineage sharing between migratory host populations and residents at breeding and wintering grounds suggest that Chilean Elaenias do not play a significant role in dispersing haemosporidian parasites, nor do they influence local transmission across South America.

In a revision of the generic classification of the tanagers, Burns et al. (2016) proposed the name Islerothraupis with type species Tanagra cristata Linnaeus, 1766 (long known as Tachyphonus cristatus); however, they overlooked a previous designation of that species as the type of a genus. In 1821, Feliks Pawel Jarocki, in the second volume of Zoologiia czyli Zwiérzętopismo Ogólne podług Naynowszego Systematu ułożone (“Zoology, or general natural history account according to the newest arranged system”), page 133, specified Tanagra cristata as the type of a proposed subgenus Loriotus. The original text in Polish is available at the website www.rcin.org.pl, the Digital Repository of Scientific Institutes, which has made a wide diversity of scholarship in Polish available over the Internet. The original description of Loriotus, in parallel with other names Jarocki introduced in his Zoologiia, is minimal: “Dziób ostro kończysty, cokolwiek zgięty. Żuchwy sczęki spodniey przy nasadzie bardzo mało zgrubiałe.” (Bill ending in a point, somewhat curved. Lower mandible slightly thickened at base.)

The puffbirds (Bucconidae) are relatively poorly studied birds whose intrafamilial relationships have not yet been explored within a phylogenetic framework in a published study. Here, we performed a parsimony analysis of osteological data obtained following the examination of all the genera and 32 out of the 36 species recognized in Bucconidae currently. The analysis yielded eight equally parsimonious trees (426 minimum steps). Ambiguous relationships were observed only in Notharcus ordii, Malacoptila fusca, and Nonnula rubecula. Notably, Bucco was polyphyletic, leading to the resurrection of Cyphos and Tamatia. In addition, the osteological data provided a well-resolved phylogeny (topological dichotomies) and the support indices indicated that most of the nodes were robust at all hierarchical levels. We thus propose the first revised classification of the Bucconidae.

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