The Mariana Crow Corvus kubaryi is a species of forest crow originally found only on the adjacent islands of Guam and Rota in the Mariana Islands of the western Pacific Ocean. Rapid and continuing declines led to it being listed by IUCN as "Critically Endangered" in 2008. Using 97 birds marked and resighted over the course of a 21 year period, we showed there was a rapid decline in first-year (fledgling to one year old) survival from 0.7 to 0.4 between 1990 and 2010, representing a doubling in mortality, and a smaller reduction in adult survival from 0.86 to 0.82 over the same period. A population model based on Leslie matrices incorporated the effects of catastrophic events, such as typhoons and human nest removal for captive breeding. All simulations predicted a precipitous decline in future populations and the inclusion of nest removals only shortened the life of the wild population by a few years. Identifying the underlying processes behind the decline in survival is the key research priority and, given the inevitable likelihood of a continuing rapid decline, conservation action should focus on securing the future of the species through captive breeding or captive rearing of wild-born chicks and ensuring that an adaptive management conservation programme is focused on countering the factors (e.g. predation) that are currently thought to impact first-year survival and productivity. Future research may identify other causes behind the Mariana Crow's decline and the conservation programme should be flexible enough to adapt to changing needs.

Island species typically exist in pathogen and predator sparse environments before human settlement, and are particularly vulnerable to the impacts of invasive species. In this study, we used the variable circular-plot method to estimate the density of birds in the highlands of Floreana Island, Galápagos Archipelago, where introduced parasites, predators, and habitat degradation are a known threat to endemic species. We recorded the number of birds seen and heard at 15 locations near Cerro Pajas Volcano in 2004 and 2008, an area that harbours the largest expanse of highland Scalesia forest on Floreana Island. We estimated the change in population density for nine bird species, including five species of Darwin’s finches. We specifically address changes in population density for the locally endemic Medium Tree Finch Camarhynchus pauper, which only occurs on Floreana Island and has a small population size. Comparing 2004 and 2008, our study found lower population density in the Medium Tree Finch, but stable population density in Small Tree Finch C. parvulus and Large Tree Finch C. psittacula. Based on data from three additional highland sites surveyed in 2008, we estimate that the maximum size of the Medium Tree Finch population is 1,620 individuals. In addition to the survey data, we observed breeding males in 2006 and 2008. We found: (1) low nesting success (six out of 63 nests produced fledglings) and high Philornis downsi parasite intensity, and (2) a biased age structure of the breeding population. No breeding males were one year old in 2006, and no males were five years old in either study year, indicating low reproductive success as well as limited lifespan. This research has contributed to the recent re-evaluation by IUCN, which has changed the Red List status of the Medium Tree Finch from ‘Vulnerable’ to ‘Critically Endangered’.

A rapidly developing tourism industry, concentrated in coastal regions, is suspected to seriously impact upon biodiversity in the global conservation priority of the insular Caribbean. In St Lucia, construction of tourism infrastructure in the coastal dry forest threatens the Endangered White-breasted Thrasher Ramphocinclus brachyurus. Long-term protection of habitat is vital, but design of such conservation action is constrained by lack of data on the species' distribution and population responses to habitat change and fragmentation. Distance sampling surveys were conducted in 2006 and 2007 to estimate numbers and map the distribution of the two remaining sub-populations. White-breasted Thrashers in St Lucia were estimated to number around 1,200 individuals, with roughly 1,050 birds occupying just over 600 ha of dry forest in the Mandelé area. We demonstrate that tourist development companies will likely soon own land constituting around 40% of the species' extent of occurrence on St Lucia, and nearly 35% globally, and that ongoing and planned tourist developments threaten around one third of the St Lucian White-breasted Thrasher population. Given the size of these potential impacts, it is vital that patches of dry forest to the west and north of a development site in the Mandelé area are safeguarded. These sites support White-breasted Thrashers at high density and are contiguous with an existing forest reserve. Other important conservation measures include preserving stands of connected mature dry and riparian forest inside the tourist development sites, alongside invasive predator control.

The marooning of populations on offshore islands can be used as a conservation technique for species threatened by introduced predators, but post-release breeding success is not always as high as expected. Following the release of Mauritius Fodies onto a partially restored islet of regenerating forest, supplementary food and control of nest parasites through the application of insecticide were used as precautionary measures to aid the establishment of a population. Nests were continuously monitored in the first three breeding seasons to inform future management decisions. The fodies built nests in taller, more mature vegetation and younger females were more likely to abandon nests before incubation started. Eggs were laid between July and February and nests made earlier in the season were more likely to fledge young. Treating nests with the insecticide carbaryl increased the probability of success, but the distance of the nest from the supplementary feeding aviaries had no effect. The number of young per female decreased each breeding season and nesting success was similar to that of fodies using exotic plantation trees on the mainland between 2002 and 2006. Future research using population models and adaptive management could lead to the withdrawal or reduction of support measures for the released population and/or the harvest of individuals to establish populations on other offshore islands.

Recently recognised as specifically distinct, the Príncipe Thrush Turdus xanthorhynchus is endemic to the island of Príncipe in the Gulf of Guinea, West Africa. Formerly treated as conspecific with the more abundant T. olivaceofuscus from the nearby island of São Tomé, the Príncipe Thrush is considered rare and likely to be restricted to primary rainforest. A 2007 survey of Príncipe comprising 177 point transect locations covering 13 sites under different land uses (six in primary forest, three in secondary forest and four in plantations) encountered 18 individuals. Thrushes were found only in primary rainforest, where overall densities were 0.10 birds ha−1, equating to a population size of 435 individuals (95% confidence intervals: 208–913). We adjusted this estimate to take into account the fact that the highest density (0.22 birds ha−1) only occurred above 600 m, giving a final estimated population size of only 364 birds (95% confidence intervals: 186–887). In light of evidence of recent declines, possibly driven by hunting pressure, in the number of mature individuals and the limited area of occurrence of the species, the IUCN Red List category for the Príncipe Thrush should be ‘Critically Endangered’ under both criteria B1a+b(iii and v) and C2a(ii). The recent designation of the primary forests of southern Príncipe as a protected area (Parque Natural d’Obô do Príncipe) provides an opportunity for the conservation of this newly described species, which we recommend is used as a flagship for the forests as a whole.

Donald (2007) showed that the adult sex ratios of wild bird populations tended to be male-biased, and that this bias was stronger in threatened species than in those of least concern. Here we show that, in 2004, the world population of the Critically Endangered Raso Lark was 65 individuals, 70% of which were male (adult sex ratio 0.70). In 2008, the population numbered approximately 175 (including juveniles) and the adult sex ratio was 0.58. Both ratios were significantly different from parity. All adult females were observed to be both paired and holding a territory. The observations therefore support Donald’s (2007) suggestion that a shortage of females can be an important constraint on the growth of threatened bird populations, a constraint that needs attention in conservation planning.

The Atiu Swiftlet Aerodramus sawtelli is endemic to the Cook Island of Atiu and has an estimated total population of less than 400, rendering it one of the world’s most globally endangered bird species. Over a series of five visits to Atiu, we collected data on the distribution of foraging swiftlets on the island, and their foraging and echolocation behaviour. The bird favours forests, agriculturally developed areas such as croplands, and populated sections of the island (e.g. gardens) but avoids the dry, upraised coral ring (makatea) of Atiu. It appears able to readily exploit new insects after they have immigrated to Atiu and may act as a natural control agent on pest species (e.g. Xyleborus perforans and Atrichopogon jacobsoni). We reanalysed the swiftlets’ echolocation calls within one of their roost caves in conjunction with new recordings. The calls do not contain ultrasonic components and are uniquely single clicks compared to the echolocation vocalisations of other swiftlet species. The minimal impact of human disturbance on the remote nesting caves of this bird suggests that its numbers, although small, represent a stable population.

We tested the hypothesis that endemic bird species of the Brazilian Atlantic forest are more sensitive to forest fragmentation than non-endemics in a fragmented landscape in northern Paraná state of southern Brazil. Levels of sensitivity (high, medium, and low) were previously determined in the landscape based on the occurrences of bird species in 14 forest fragments. We evaluated 112 forest bird species and found that endemic species were more sensitive than non-endemics. Among the endemic species, highly sensitive species tended to have smaller geographic ranges. In a second analysis, we determined that birds at the edges of their geographic ranges in northern Paraná were more vulnerable to forest fragmentation. Combining both factors we found that endemic birds at the edge of their ranges were the most sensitive to fragmentation. Our results suggest that endemics and species at the edges of larger ranges might need larger tracts to ensure their continued existence within that region. Our results, however, also indicate that even small forest fragments may have considerable value for non-endemics and for species closer to the centres of their ranges.

The ability of birds to move through the landscape is a key parameter for ecological and conservation studies. We studied bird movements among natural vegetation patches surrounded by native grassland and tested the effect of inter-patch distance on bird movements/hour and assessed the distances travelled for species of different body mass. We made observations of 1,138 bird movements among 11 forest patches and banded 368 birds obtaining 69 recaptures (42 recaptures in the same patch where the birds were banded and 27 recaptures in other patches). We used seven patches as observation points and capture sites in the Pantanal wetland, Brazil during one year. Movements/hour decreased significantly with inter-patch distance. Median or maximum distance travelled increased significantly with body mass. Small-bodied Passeriformes, however, did not increase the distance travelled with body mass, since they seldom moved more than 286 m. The majority of forest dependent or semi-dependent birds seem able to adapt to natural fragmented landscapes. However, small forest patches may be inappropriate habitat for many large-bodied species, and it is more difficult for small-bodied species to use more isolated forest patches. Thus, size and spatial arrangement of habitat patches may act as a filter in which large and close fragments seem to protect the highest number of bird species. The findings of this study indicate that stepping stones provide a viable alternative to continuous biological corridors if the latter are not available. However, the type of species in an area and the size and distance between vegetation patches are all critical factors that must be considered in projects that aim to use forest patches as stepping stones to increase or maintain local bird biodiversity.

The current ranges of many tropical species of conservation concern are poorly known, yet this information is critical for assessing their conservation status against the IUCN Red List criteria and implementing species-level management. Antpittas in the genera Grallaria and Grallaricula are elusive, ground-foraging insectivores, highly susceptible to a range of threats. For these genera, we combine environmental niche modelling with expert knowledge in order to predict species’ geographic distributions, and we use current estimates of deforestation to evaluate their conservation status in Ecuador. We use BIOCLIM to generate a first pass geographic prediction, which was further aided by expert knowledge of their natural history. This methodology allowed us to assess the conservation status of each species, revising previous assessments at the national level and making recommendations for revision of global IUCN Red List categories. Based on inferred rates of population decline, derived from estimates of loss of suitable habitat, we suggest ranking three species as ‘Endangered’ in Ecuador, one as 'Vulnerable', and three as ‘Near Threatened’. Predicted national ranges vary in size from 56.05 km2 to 112,745 km2. Patterns of range loss were different for each Andean slope, with higher deforestation on the western slope. The combination of niche modelling and knowledge of habitat loss can be a powerful tool to aid conservation efforts in the face of a poor understanding of population demographics, as is the case for many Neotropical taxa. We hope the methodology and results provided here will increase our understanding, and focus future attention on the conservation of this poorly known avian group.

Deforestation, fragmentation and habitat disturbance may alter the relationship between pathogens and hosts. We tested, apparently for the first time, whether habitat fragmentation and degree of dependence on forests affect the prevalence of avian blood parasites. We estimated the prevalence of Plasmodium, Haemoproteus and Trypanosoma through the inspection of 925 blood smears from 109 species captured in six pairs of small (< 30 ha) and large (> 1,000 ha) Brazilian Atlantic Forest fragments. Prevalence of the three types of parasites did not differ between small and large forest patches. Forest-independent birds were usually more infected with Plasmodium and Haemoproteus than other birds, but forest-dependent birds were more infected with Trypanosoma. Parasite richness on birds was not affected by patch size.

The Taita Apalis Apalis fuscigularis (IUCN category: Critically Endangered) is a species endemic to south-eastern Kenya. We assessed population size and habitat use in the three forest sites in which it is known to occur (Ngangao, Chawia and Vuria, totalling 257 ha). The estimate of total population size, derived from distance sampling at 412 sample points, ranged from 310 to 654 individuals, with the northern section of Ngangao fragment having 10-fold higher densities than Chawia (2.47–4.93 versus 0.22–0.41 birds ha−1). Ngangao north alone hosted 50% of the global population of the species. The highly degraded Vuria fragment also had moderately high densities (1.63–3.72 birds ha−1) suggesting that the species tolerates some human disturbance. Taita Apalis prefers vegetation with abundant climbers, but the predictive power of habitat use models was low, suggesting that habitat structure is not a primary cause for the low density of the species in Chawia. Protecting the subpopulation in the northern section of Ngangao is a priority, as is identifying factors responsible of the low abundance in Chawia, because ameliorating conditions in this large fragment could substantially increase the population of Taita Apalis.