Following habitat fragmentation, species are predicted to go locally extinct from remnant patches in a predictable order due to differential extinction vulnerabilities. This selective species loss will result in nested distributions of species such that species found in depauperate patches will also tend to be found in larger, more speciose patches. Therefore, it should be possible to determine the relationship between species-specific characteristics and extinction vulnerability by comparing the order in which species are nested [i.e. nestedness ranking (NR)] with various natural history characteristics available from the literature and/or collected in the field. In this study, we investigate the relationship between the NRs of 41 resident forest-interior bird species inhabiting recently isolated landbridge islands in Lago Guri, Venezuela, with a large number of natural history characteristics collected from the literature (regional abundance, body length, habitat specificity, trophic guild, sensitivity to disturbance, range size) and from the field (local population density). In a comparison of the best regression models generated using just variables available through the literature (i.e. no local population density) with the best model generated using all possible variables, we found that the inclusion of field-based data significantly improved the amount of variation explained. The best overall model (r 2 = 0.40, Po0.001) included body size, habitat specificity, zoogeographic distribution (a measure of range size) and local population density as predictors of NR. Understanding the factors that influence extinction vulnerability has important implications for conservation and could be used to help direct management efforts.

Accurate maps of species ranges are essential to inform conservation, but time-consuming to produce and update. Given the pace of change of knowledge about species distributions and shifts in ranges under climate change and land use, a need exists for timely mapping approaches that enable batch processing employing widely available data. We develop a systematic approach of batch-processing range maps and derived Area of Habitat maps for terrestrial bird species with published ranges below 125,000 km2 in Central and South America. (Area of Habitat is the habitat available to a species within its range.) We combine existing range maps with the rapidly expanding crowd-sourced eBird data of presences and absences from frequently surveyed locations, plus readily accessible, high resolution satellite data on forest cover and elevation to map the Area of Habitat available to each species. Users can interrogate the maps produced to see details of the observations that contributed to the ranges. Previous estimates of Areas of Habitat were constrained within the published ranges and thus were, by definition, smaller—typically about 30%. This reflects how little habitat within suitable elevation ranges exists within the published ranges. Our results show that on average, Areas of Habitat are 12% larger than published ranges, reflecting the often-considerable extent that eBird records expand the known distributions of species. Interestingly, there are substantial differences between threatened and non-threatened species. Some 40% of Critically Endangered, 43% of Endangered, and 55% of Vulnerable species have Areas of Habitat larger than their published ranges, compared with 31% for Near Threatened and Least Concern species. The important finding for conservation is that threatened species are generally more widespread than previously estimated.

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Article impact statement: Conservation triage is not necessary for species conservation. Adequate resources exist; even species with small populations can recover.

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