Setting Favourable Reference Values (FRVs) can assist the definition of the conservation status of a species. FRVs may consider population, habitat, and range. FRVs can indicate a range of values for different parameters, which should allow the long-term persistence of a species/population. We propose a method for the definition of reference values for the habitat (FRV-H or HRV) of breeding bird species. HRV should cover habitat extent and quality, both required to ensure long-term persistence. Extent HRV should express a measure of suitable area, whereas quality HRV could be defined as the range of values for habitat variables known to affect habitat quality. To define an extent HRV, we built species distribution models (SDMs) and set extent HRV as the extent of potentially suitable habitat under a conservative approach. Quality HRV should refer to environmental determinants/correlates of occurrence and breeding success, and should be defined by the identification of the habitat factors affecting occurrence and reproduction. When habitat selection is adaptive, habitat suitability may approximate habitat quality, being correlated with breeding success. In that case, fine-scaled habitat/distribution models may be used to identify determinants/correlates of reproductive output, and such species-habitat relationships may help define quality HRV. We show examples using the Red-backed Shrike Lanius collurio as a model. The use of habitat selection models, which can be made spatially explicit generating distribution models, may assist the definition of both extension and quality HRVs. Species-habitat models can allow the individuation of factors and relative values affecting species occurrence/reproduction (quality HRV), and the definition of the spatial distribution and quantity of potentially suitable habitat (extent HRV). Our approach is one of the possible ones, aiming at finding a “suitable” trade-off between affordable data and scientific precision. HRVs should be used together with population and range FRVs to assess the status of a species/population.

Populations of three vulture species of the genus Gyps, the Egyptian Vulture Neophron percnopterus and Red-headed Vulture Sarcogyps calvus have declined markedly on the Indian subcontinent since the mid-1990s and all are now Critically Endangered or Endangered. Gyps vultures have been killed by the widely used non-steroidal anti-inflammatory drug diclofenac, ingested when they feed on carcasses of domesticated ungulates treated with the drug shortly before death. However, it is not known whether Egyptian Vulture and Red-headed Vulture are also sensitive to diclofenac. Veterinary use of diclofenac was banned in India in 2006. Since then, the prevalence and concentration of diclofenac in domesticated ungulates carcasses has decreased and population declines of Gyps vultures have slowed or reversed. Here, we examine counts of Egyptian and Red-headed Vultures obtained on road transects in and near protected areas between 1992 and 2011. We found indications that the declines in both species appear to have slowed and possibly increased after the ban was introduced, though the small numbers of birds counted make this conclusion less robust than that for the Gyps species. These results suggest that both species may have been adversely impacted by diclofenac and that government bans on this drug, which are beginning to take effect, may benefit a wider range of vulture species in the Indian subcontinent than was previously thought.

Three Critically Endangered Gyps vultures endemic to South Asia continue to decline due to the use of diclofenac to treat livestock. High nephrotoxicity of diclofenac to Gyps vultures, leading to death, has been established by experiment and observation, in four out of five Gyps vulture species which occur in South Asia. Declines have also been observed in South Asia’s four other non-Gyps vulture species, but to date there has been no evidence about the importance of diclofenac as a potential cause. Neither is there any evidence on the toxicity of diclofenac to the Accipitridae other than vultures. In this study, gross and microscopic lesions and diclofenac tissue levels in Steppe Eagles Aquila nipalensis found at a cattle carcass dump in Rajasthan, India, show evidence of the toxicity of diclofenac for this species. These findings suggest the possibility that diclofenac is toxic to other accipitrid raptors and is therefore a potential threat to much wider range of scavenging species in South Asia.

The “Critically Endangered” Beck’s Petrel Pseudobulweria becki has been recorded regularly in the Bismarck Sea during the past five years, but its nesting grounds are yet to be located. Previously, over 70 years elapsed between the collection of the original specimens in 1928 and 1929, and the next confirmed observations in 2007. We evaluate over 40 documented records of the species as well as recorded survey effort within the Bismarck Archipelago and Solomon Islands and we assess potential breeding areas as well as land and sea priority search areas. On current evidence, southern New Ireland, within the Bismarck Archipelago, remains the highest priority area to search for nesting colonies but other parts of the region also warrant further investigation. The species’s distribution, population size and trends, ecology and threats are all poorly known, so prescribing conservation actions is difficult. As a starting point we identify the most important research actions to advance current knowledge, recognising that locating the nesting grounds of the Beck’s Petrel remains the prime conservation priority for this species.

The Black Woodpecker Dryocopus martius is the largest woodpecker of the Palearctic Region and it has been recognised as a keystone species whose presence provides critical resources to secondary cavity-users in European forest ecosystems. Here we investigate cavity tree and foraging-habitat selection of Black Woodpecker in three natural parks located in the central and eastern Italian Alps and included in the Natura 2000 network. A total of 94 cavity trees were identified, showing a minimum diameter of 35 cm and a mean diameter of 51 cm. We counted 30 active nests, but only 40% were newly excavated. Silver fir Abies alba and larch Larix decidua were preferred as cavity trees, with silver fir also associated with habitat surrounding the cavity trees. Norway spruce Picea abies and Silver fir were found to be positively associated with the surroundings of feeding sites. Logistic regression models identified the average diameter at breast height and the average tree crown height as significant predictors, positively associated with both cavity trees (AUC: 0.988) and cavity tree plots (AUC: 0.866). Also, the total volume of dead logs and the percentage of understorey cover turned out to be significant predictors of feeding sites, showing a positive and a negative association, respectively (AUC: 0.708). Cross validation of logistic regression models indicated that only cavity tree models can be considered useful tools in conservation practice. Overall, our results indicated that the Black Woodpecker behaves like an opportunist when choosing feeding sites. On the other hand, our results also indicate that the Black Woodpecker clearly behaves as a demanding species when it selects cavity trees, showing a hierarchical pattern in habitat selection and a marked preference for large trees with high crown height. We discuss the implications of our results for the conservation of the Black Woodpecker in Natura 2000 alpine sites.

The accurate estimation of key demographic parameters is invaluable for making decisions about the management of endangered wildlife but such estimates are often difficult to obtain. Parameters such as species-specific apparent survival rates are an important component in understanding population ecology and informing management decisions. The Maui Parrotbill Pseudonestor xanthophrys is a ‘Critically Endangered’ Hawaiian honeycreeper endemic to the Island of Maui. We used an 18-year encounter history dataset comprising 146 marked individuals to estimate apparent survival between sexes and age classes (juvenile, adult). A difference in survival rates between sexes was strongly supported; 0.72 ± 0.04 for adult females and 0.82 ± 0.03 for adult males. This difference may be a reflection of either reproductive costs or additional risks of incubation and brooding, such as depredation. We also found support for age-biased survival, but limited information for juveniles did not provide a well-supported model fit for our data (juvenile survival = 0.17 ± 0.15; adults = 0.78 ± 0.02). However, apparent adult survival was similar to that of other Hawaiian passerines (mean 0.78 ± 0.03, n = 16). These results suggest that efforts to prevent the extinction of this species may benefit from future management strategies focused on increasing female survival such as predator reduction.

Source-sink dynamics are easily overlooked when formulating recovery objectives for threatened species. This could lead to unrealistic criteria imposed on sink populations, which in turn might restrict an entire metapopulation from being delisted. Therefore, an understanding of the viability of subpopulations within the context of a metapopulation is needed to develop appropriate recovery objectives. Consequently, we used 11 years of mark-recapture, productivity, and movement data to analyse the viability of a small, geographically isolated population of the Snowy Plover Charadrius nivosus, a shorebird listed as threatened under the U.S. Endangered Species Act. Simulations confirmed that the focal population in northern California is a sink that relies upon immigrants from neighbouring populations. Furthermore, these source populations will increase within the next 50 years and are likely to achieve the delisting requirements. However, the northern California population is unlikely to reach the delisting criteria given the current vital rate estimations. Management scenarios demonstrated that lethal predator removal and reducing human disturbance facilitate population recovery and may partially alleviate the reliance upon immigration. However, the use of nest exclosures reduced population growth because they are known to compromise adult survival. These results highlight the importance of maintaining viable source populations and re-evaluating the recovery objectives of metapopulations with active sinks.

Breeding dispersal subsequent to nest failure is hypothesised to be a behavioural response to danger posed by nest predators. We used histories and locations of male and female Snowy Plover Charadrius nivosus nests in northern California over a 10-year period to examine effects of nest fate, mate fidelity, residency, predator exclosures, and age on dispersal distance. Within years, females moved a median distance of 2.2 km after changing mates; males moved a median of 0.9 km. Between years, plovers moved the shortest distances when they retained a mate from the prior year and were successful in hatching eggs (males = 0.2 km, females = 0.3 km). Both females (13.0 km) and males (2.6 km) dispersed farther when mate change coincided with nest failure in the prior year. The observation that most plovers did not disperse far enough to move away from sites where predators are abundant and have strong effects on plover reproductive success suggests that effective predator management will be challenging.

Following a recent assessment of the distribution and habitat use of Gurney’s Pitta in Myanmar (Burma), further extensive surveys were undertaken in 2010, 2011 and 2012. These have extended the species’ known altitudinal limit to between 250 m and 300 m asl and its latitudinal limit to above 12.5°N, around 80 km north of the northernmost historical record, although the species was recorded far less frequently at higher altitudes and latitudes. Birds were recorded in a range of forested habitats, from intact primary forest to secondary and bamboo forest, with no significant difference between major forest types in the likelihood of occurrence. Niche envelope modelling (MaxEnt) suggested a total range size in Myanmar of 3,379 km2, and did not identify any potentially suitable areas in adjacent parts of Thailand. The species’ preference for warmer, wetter areas on flat ground, conditions ideal for growing oil palm and rubber, suggest that its distribution is likely to contract in the near future. The entire range of Gurney’s Pitta in Myanmar falls within the part of the country most suitable for commercial oil palm production, although the projected yields within its range are low to moderate. Field surveys found evidence of rapid recent deforestation and high levels of hunting and trapping in many parts of the region. The species’ range in Myanmar does not overlap with any protected areas. The protection of southern Myanmar’s biodiversity will require substantial investment by foreign conservation interests, sympathetic land-use planning and the strengthening of environment legislation. Protection of extensive tracts of lowland forest within the range of Gurney’s Pitta, particularly the proposed Lenya National Park and the adjacent Ngawun and Htaung Pru Reserve Forests, is urgently needed. Conserving these areas will also protect populations of other globally threatened bird and mammal species.

Despite the recent rapid decline of many grassland bird species, the relative importance of habitat configuration to population persistence is unclear. We used Southeastern American Kestrels Falco sparverius paulus in north-central Florida as a model system to explore the relative influence of landscape structure components on site occupancy patterns at two spatial scales, and for two different time periods. We focused on the dynamic processes of site-level population expansion or contraction. We modelled the occupancy of 131 American Kestrel nest boxes with Bayesian state-space dynamic occupancy models that considered both the partially observed process of true occupancy and the probability of detection of occupancy. We used reversible jump Markov chain Monte Carlo (RJMCMC) algorithms to identify variables that described the continued occupancy of nest boxes, or ϕ, and the probability of colonisation of nest boxes between time periods, or γ3. Changes in open habitat patch isolation at a fine scale, as estimated by the variability of nearest neighbour distance, predicted site colonisation between decades, and patch shape variability was related to ϕ during the early time period (1992–93). We found no strong effects of landscape structure on ϕ during the later time period (2008–2010). We also found no evidence for effects of loss of open habitat on box occupancy or colonization. Our results indicate that continued habitat fragmentation would be deleterious for this threatened subspecies. Additionally, certain land cover management practices recommended for the Florida sandhills, such as frequent low-intensity controlled burns, will likely help conservation attempts.

Pallas’s Fish Eagle Haliaeetus leucoryphus (PFE) is sparsely distributed across a vast swathe of central, eastern and southern Asia, and is classified as ‘Vulnerable’ by IUCN on the basis of population size and reports of declines in many areas. Mongolia has long been considered a breeding stronghold for the species, but evidence to support this is unclear. Our objective was to assess the current distribution and status of the PFE in Mongolia to enable a more accurate assessment of the species’ conservation status, through collation of existing information from the historical literature, and a contemporary survey of historical sites and potential PFE breeding habitat. Thirty-four traceable locations were identified in the historical literature, of which breeding activity had been recorded in seven. Field surveys were conducted at a total of 77 sites throughout the study period (2005–2011) between April and October, including 21 of the historical PFE locations. PFE were observed at eight sites, all of which were historical PFEs locations, and no evidence of breeding activity was recorded. These findings suggest that Mongolia is not (and may never have been) a breeding stronghold for the PFE. The lack of eagles at 13 of 21 historical sites surveyed, coupled with a lack of sightings of birds at alternative locations is suggestive of a decline in site occupancy. Observations of juvenile eagles within one month of the spring thaw suggests that at least a proportion of Mongolian PFEs are breeding at southern latitudes, and future studies to establish these migratory linkages are warranted. These findings, coupled with evidence of declines in other parts of the PFE range indicate a need to re-evaluate the species’ conservation status, and in particular to determine the number of mature PFEs present in suitable habitat in the Indian Subcontinent and Myanmar between November and March.

The Red-fronted Macaw Ara rubrogenys is endemic to Bolivia, where it is listed as “Critically Endangered” due to its reduced population size and persisting threats. This species is known to breed exclusively on steep cliffs in arid inter-Andean valleys. However, during a survey of the whole distribution, we noted a previously overlooked population breeding in stands of the also endemic and globally endangered palm Parajubaea torallyi. We observed five adult pairs and confirmed at least three active nests. Nests were in holes 14–20 m above the ground in dead palms, at 2,580–2,700 m asl. The scarcity of breeding habitat and current nest poaching were identified as the major threats for this population. This discovery broadens our understanding of the breeding ecology and widens the scope of action for the monitoring and conservation of the species.