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The forest inventory surveys in the bird area were initiated in 1981 and transects were made permanent in 1991. The inventory is representative of approximately 2.5 km-squared of mid elevation northern hardwood forest. It consists of a total inventory of all trees >=10 cm dbh, within each of four 10 m wide belt transects. The parallel transects are placed approximately 200 m apart and run roughly in an east-west direction for 2200 to 2900 m. In 1991, each live stem >=10 cm dbh was tagged with a unique number. Tree vigor is assessed every two years and diameter is remeasured every ten years. Every two years, new tags are placed on stems that have grown into the 10 cm diameter class. A survey of smaller trees (>=2 to <10 cm dbh) was first taken in 1991 and is resurveyed every ten years. This dataset includes the initial inventory values measured in 1981. The full timeline of tree inventory data for this site is available at https://doi.org/10.6073/pasta/58dfdebfd1b6440510def2394ab92c53 These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

Ecological niches are pivotal in addressing questions of species richness gradients like the Latitudinal Diversity Gradient (LDG). The Hutchinsonian niche hypervolume model and derivatives are some of the most proven tools. Accordingly, species occupy mathematically convenient spaces in relation to functional, especially trophic, relationships, as well as the physical environment. In one application, the number of species in a community is a function of average niche sizes, overlaps, and total niche volume. Alternatively, the number of coexisting species derives from invasibility criteria in relation to species-interaction modules. The daunting complexity of tropical communities begs the question of how well these ecologically inspired paradigms accommodate present knowledge of species interactions and functional relationships. Recent studies of hyperdiverse tropical insectivorous bird species suggests reevaluating the applicability of such concepts. Here I review Neotropical, arthropod-feeding bird species interactions needed to explain these species’ trophic relationships, including their diets, feeding substrates, and behavioral and morphological traits relevant to resource acquisition. Important emergent generalizations include extraordinary specializations on both prey resource locations (substrates) and behaviors, rather than on particular resourcesper se, and a preponderance of adaptations to exploit the anti-predator traits of prey, traits evolved in response to other predators. These specializations and implicit arms races necessitate evolutionary approaches to niches necessary to understand the relevant natural history and ecology, how these species compete interspecifically, and even how these predator species interact with preyviaevolutionary enhancements. These findings, compared and contrasted with prevailing concepts and findings, suggest expanding niche concepts to accommodate both the large temporal and regional geographic scales to understand the accumulated species richness of the mainland Neotropics. These trophic specializations also highlight why many of these birds are so sensitive to human disturbances, especially habitat loss, fragmentation, and degradation. 

Abstract  The Puerto Rican Tody’s scientific name Todus mexicanus prompts the question of how an endemic Puerto Rican species acquired such a confusingly inappropriate name. Here we address the nomenclatural history of this species to address how and when this misnomer arose, and we use this case study to discuss the pros and cons of changing scientific names. We argue that a variety of circumstances warrant changing mexicanus to borinquensis, despite strong opposition based on International Commission on Zoological Nomenclature rules discouraging changes of toponyms (names based on geographical locations). We discuss several alternatives for the change, emphasizing the potential role of Puerto Ricans. Keywords  conservation, International Commission on Zoological Nomenclature, Latin names, nomenclatural history, Puerto Rican Tody, Todidae, Todus mexicanus Resumen  El San Pedrito de Puerto Rico (Todus mexicanus): ¿Qué hay en un nombre? • El nombre científico del San Pedrito de Puerto Rico, Todus mexicanus, plantea la pregunta de cómo una especie endémica de Puerto Rico adquirió un nombre tan confusamente inapropiado. Aquí abordamos la historia nomenclatural de esta especie para entender cómo y cuándo surgió este error de denominación, y utilizamos este estudio de caso para discutir los pros y los contras de cambiar los nombres científicos. Argumentamos que una variedad de circunstancias justifican cambiar mexicanus a borinquensis, a pesar de la fuerte oposición basada en las reglas de la Comisión Internacional de Nomenclatura Zoológica que desaconsejan los cambios de topónimos (nombres basados en ubicaciones geográficas). Discutimos varias alternativas para el cambio, destacando el papel potencial de los puertorriqueños. Palabras clave  Comisión Internacional de Nomenclatura Zoológica, conservación, historia nomenclatural, nombres científicos, San Pedrito de Puerto Rico, Todidae, Todus mexicanus Résumé  Le Todier de Porto Rico (Todus mexicanus) : qu’est-ce qu’un nom ? • Le nom scientifique du Todier de Porto Rico Todus mexicanus soulève la question de savoir comment une espèce endémique portoricaine a pu acquérir un nom aussi inapproprié qui prête à confusion. Nous abordons ici l’histoire nomenclaturale de cette espèce afin de déterminer comment et quand cette erreur de nom est apparue, et nous utilisons cette étude de cas pour discuter des avantages et des inconvénients d’un changement de nom scientifique. Nous soutenons que plusieurs considérations justifient le changement de mexicanus en borinquensis, malgré une forte opposition fondée sur les règles de la Commission internationale de nomenclature zoologique décourageant les changements de toponymes (noms basés sur des emplacements géographiques). Nous examinons plusieurs possibilités de changement, en insistant sur le rôle potentiel des Portoricains. Mots clés  Commission internationale de nomenclature zoologique, conservation, histoire nomenclaturale, Todidae, Todier de Porto Rico, Todus mexicanus 

Abstract The extent to which interspecific competition structures species interactions and coexistence within communities, and the relevant mechanisms, are still debated. We focus on New World wood warblers (Parulidae), beginning with Robert MacArthur’s iconic 1958 paper in which he shows how subtle foraging behaviors, purportedly linked to dietary differences, within spruce trees contribute to the coexistence of 5 spruce-woods warbler species. MacArthur coined the phrase “resource partitioning”, and profoundly impacted the field of Ecology for subsequent decades in diverse ways. To understand what MacArthur got right and what he missed, we reviewed both ecological and evolutionary approaches to questions of the origin and coexistence of competing species in the context of diet. We argue that an important, underappreciated, mechanism of competition among coexisting migratory warbler species, particularly in winter, is diffuse exploitation competition, based in part on our own studies of warbler diets in relation to foraging behavior, substrate use, bird morphology, and other traits. Our review and synthesis of interspecific competition and coexistence in warblers have important consequences, including our questioning of the importance and effectiveness of resource partitioning in birds. We also suggest a novel hypothesis for the success of warblers today in the Caribbean and other habitats, beginning with their relatively recent adaptive radiation and the ecological opportunity on Caribbean islands. 

Epigraph: “The house is burning. We do not need a thermometer. We need a fire hose.” (P. 102, Janzen and Hallwachs,2019). Insectivorous birds are declining widely, and for diverse reasons. Tropical insectivorous birds, more than 60% of all tropical birds, are particularly sensitive to human disturbances including habitat loss and fragmentation, intensive agriculture and pesticide use, and climate change; and the mechanisms are incompletely understood. This review addresses multiple, complementary and sometimes synergistic explanations for tropical insectivore declines, by categorizing explanations into ultimate vs. proximate, and direct versus indirect. Ultimate explanations are diverse human Anthropocene activities and the evolutionary history of these birds. This evolutionary history, synthesized by the Biotic Challenge Hypothesis (BCH), explains tropical insectivorous birds' vulnerabilities to many proximate threats as a function of both these birds' evolutionary feeding specialization and poor dispersal capacity. These traits were favored evolutionarily by both the diversity of insectivorous clades competing intensely for prey and co-evolution with arthropods over long evolutionary time periods. More proximate, ecological threats include bottom-up forces like declining insect populations, top-down forces like meso-predator increases, plus the Anthropocene activities underlying these factors, especially habitat loss and fragmentation, agricultural intensification, and climate change. All these conditions peak in the lowland, mainland Neotropics, where insectivorous bird declines have been repeatedly documented, but also occur in other tropical locales and continents. This multiplicity of interacting evolutionary and ecological factors informs conservation implications and recommendations for tropical insectivorous birds: (1) Why they are so sensitive to global change phenomena is no longer enigmatic, (2) distinguishing ultimate versus proximate stressors matters, (3) evolutionary life-histories predispose these birds to be particularly sensitive to the Anthropocene, (4) tropical regions and continents vary with respect to these birds' ecological sensitivity, (5) biodiversity concepts need stronger incorporation of species' evolutionary histories, (6) protecting these birds will require more, larger reserves for multiple reasons, and (7) these birds have greater value than generally recognized. 

Abstract Identifying the composition of avian diets is a critical step in characterizing the roles of birds within ecosystems. However, because birds are a diverse taxonomic group with equally diverse dietary habits, gaining an accurate and thorough understanding of avian diet can be difficult. In addition to overcoming the inherent difficulties of studying birds, the field is advancing rapidly, and researchers are challenged with a myriad of methods to study avian diet, a task that has only become more difficult with the introduction of laboratory techniques to dietary studies. Because methodology drives inference, it is important that researchers are aware of the capabilities and limitations of each method to ensure the results of their study are interpreted correctly. However, few reviews exist which detail each of the traditional and laboratory techniques used in dietary studies, with even fewer framing these methods through a bird-specific lens. Here, we discuss the strengths and limitations of morphological prey identification, DNA-based techniques, stable isotope analysis, and the tracing of dietary biomolecules throughout food webs. We identify areas of improvement for each method, provide instances in which the combination of techniques can yield the most comprehensive findings, introduce potential avenues for combining results from each technique within a unified framework, and present recommendations for the future focus of avian dietary research. 

Although both interspecific competition and coexistence mechanisms are central to ecological and evolutionary theory, past empirical studies have generally focused on simple (two‐species) communities over short time periods. Experimental tests of these species interactions are challenging in complex study systems. Moreover, several studies of ‘imperfect generalists’, consistent with Liem's Paradox, raise questions about the ability of evolved species differences to partition niche space effectively when resources vary considerably across the annual cycle. Here we used a recently developed theoretical framework to combine past research on population‐level processes with observational data on resource use to test for ongoing interspecific competition and understand the nature of resource overlap. We compared species diet overlaps and differences in several distinctive communities centred on a focal species, the American RedstartSetophaga ruticillareplicated both spatially and seasonally, in combination with documentation of population regulation to assess the ability of similar species to partition dietary niche space and limit interspecific competition. Our results document high dietary overlap in most of the communities studied, with only subtle differentiation consistent with known species differences in foraging behaviour and morphology. These findings are largely consistent with species foraging as imperfect generalists. However, in contrast to past studies, the high diet overlaps observed here during times of inferred resource scarcity were driven by low‐value prey taxa (e.g. small ants) and did not involve truly ‘private’ resources. All of these factors increase the potential negative impacts of interspecific competition, and limit the ability of these birds to avoid competition if food availability deteriorates further than observed in our study, either seasonally or at longer intervals. 

ABSTRACT MotivationHere, we make available a second version of the BioTIME database, which compiles records of abundance estimates for species in sample events of ecological assemblages through time. The updated version expands version 1.0 of the database by doubling the number of studies and includes substantial additional curation to the taxonomic accuracy of the records, as well as the metadata. Moreover, we now provide an R package (BioTIMEr) to facilitate use of the database. Main Types of Variables IncludedThe database is composed of one main data table containing the abundance records and 11 metadata tables. The data are organised in a hierarchy of scales where 11,989,233 records are nested in 1,603,067 sample events, from 553,253 sampling locations, which are nested in 708 studies. A study is defined as a sampling methodology applied to an assemblage for a minimum of 2 years. Spatial Location and GrainSampling locations in BioTIME are distributed across the planet, including marine, terrestrial and freshwater realms. Spatial grain size and extent vary across studies depending on sampling methodology. We recommend gridding of sampling locations into areas of consistent size. Time Period and GrainThe earliest time series in BioTIME start in 1874, and the most recent records are from 2023. Temporal grain and duration vary across studies. We recommend doing sample‐level rarefaction to ensure consistent sampling effort through time before calculating any diversity metric. Major Taxa and Level of MeasurementThe database includes any eukaryotic taxa, with a combined total of 56,400 taxa. Software Formatcsv and. SQL. 

Abstract Understanding the geographic linkages among populations across the annual cycle is an essential component for understanding the ecology and evolution of migratory species and for facilitating their effective conservation. While genetic markers have been widely applied to describe migratory connections, the rapid development of new sequencing methods, such as low‐coverage whole genome sequencing (lcWGS), provides new opportunities for improved estimates of migratory connectivity. Here, we use lcWGS to identify fine‐scale population structure in a widespread songbird, the American Redstart (Setophaga ruticilla), and accurately assign individuals to genetically distinct breeding populations. Assignment of individuals from the nonbreeding range reveals population‐specific patterns of varying migratory connectivity. By combining migratory connectivity results with demographic analysis of population abundance and trends, we consider full annual cycle conservation strategies for preserving numbers of individuals and genetic diversity. Notably, we highlight the importance of the Northern Temperate‐Greater Antilles migratory population as containing the largest proportion of individuals in the species. Finally, we highlight valuable considerations for other population assignment studies aimed at using lcWGS. Our results have broad implications for improving our understanding of the ecology and evolution of migratory species through conservation genomics approaches.