The island of Buru in Maluku province, Indonesia was visited in November and December 1989. Using a point count method, we assessed the conservation status of the island's restricted-range lowland birds by examining their abundance and habitat associations. Thirteen of Buru's 19 lowland restricted-range species were recorded during the fieldwork. Of these we assign nine (White-eyed Imperial Pigeon Ducula perspicillata, Moluccan Red Lory Eos bornea, Bum Racquet-tail Prioniturus mada, Black-tipped Monarch Monarcha loricatus, White-naped Monarch Monarcha pileatus, Dark-grey Flycatcher Myiagra galeata, Flame-breasted Flowerpecker Dicaeum erythrothorax, Bum Yellow White-eye Zosterops buruensis and Black-faced Friarbird Philemon moluccensis) to IUCN's Safe/Low risk category of threat, on the basis of their large populations, widespread occurrence on Bum and association with non-pristine habitats. We recommend that the remaining six of the recorded species remain Data-deficient but some of these (e.g. Blue-fronted Lorikeet Charmosyna toxopei and Bum Cuckoo-shrike Coracina fortis) may be Vulnerable. While data on the birds which we did not record are obviously needed, we suggest that the amount of forest remaining, the abundance of many species and their tolerance of selectively logged forests bodes well for the immediate future of the bulk of Buru's lowland avifauna.

We evaluated the abundance and distribution of low-elevation forest birds on windward Hawai'i Island during August 1993-February 1994, and present evidence of changes in the species composition of the forest bird community since 1979. Endemic Hawaiian birds occurred in native-dominated forests as low as 120 m elevation. Non-native species were detected at all survey locations. We observed non-native Saffron Finch Sicalis flaveola, previously unrecorded in Puna. Variable circular plot surveys of Kahauale'a Natural Area Reserve indicated the disappearance of two native species ('I'iwi Vestiaria coccinea and 'O'u Psittitostra psittacea), and two non-native additions (Red-billed Leiothrix Leiothrix lutea and Kalij Pheasant Lophura leucomelana) to the study area since the Hawai'i Forest Bird Survey conducted in 1979. We present evidence that native 'Elepaio Chasiempsis sandwichensis has experienced a decrease in population density and an elevational range contraction since 1979. Surveys indicate Puna's forest bird community has had increasing aliens and declining native species since 1979. The persistence of some native bird species within the range of avian disease vectors such as Culex quinquefasciatus in forests below 1,000 m elevation presents an important enigma that requires additional study.

Birds that are long-distance migrants partition their annual cycle among a number of locations over a large spatial range. The conservation of these species is particularly complex because it requires attention to a number of different and distant habitats based on knowledge of migratory phenology, routes and staging areas. In the case of the globally threatened Aquatic Warbler Acrocephalus paludicola, a habitat specialist that breeds in Europe and spends the boreal winter in sub-Saharan Africa, non-breeding staging areas were widely unknown until recently. We applied light-level geolocators to adult male Aquatic Warblers at breeding sites in Belarus and Ukraine. Data from eight retrieved geolocators confirmed a south-west and then westward migration route through Europe via the northern Mediterranean with staging sites on the Iberian Peninsula and occasionally France and north-west Africa. In sub-Saharan Africa, final staging areas were in Mali, either in the Inner Niger Delta or at (presumably) small water bodies in the desert, with one bird most likely staying in the north of Ivory Coast south of the previously assumed range. The birds probably stayed in the final staging areas for most of the non-breeding season, but the logger on only one bird provided data throughout the entire migration cycle. Pre-nuptial migration of the latter was by a more easterly route than the southward migration. Our study suggests that conservation strategies for Aquatic Warbler north of the Sahara should include consideration of unknown staging sites in the northern Mediterranean as well as on the Iberian Peninsula and in north-west Africa. South of the Sahara, our study demonstrates the importance of the Sahel for the conservation of the Aquatic Warbler, including both the major floodplains of the Niger River and small Sahelian wetlands that are under pressure from human development.

We examined the influence of forest fragmentation and resource availability on the abundance and distribution of Sumba Hornbill Aceros everetti, a large, canopy-dwelling bird endemic to Sumba Island, Indonesia. Hornbill numbers were estimated monthly from August 1998 to September 1999. Estimates were made in three large (≥1,000 ha) and three small (<1,000 ha) forest fragments, using a standard line transect method. Phenological patterns of canopy trees were assessed in 10 × 50 m plots. Our data indicated that forest patch size may be a better predictor of Sumba Hornbill abundance and distribution than overall resource availability. Hornbills occurred at higher densities in large forests (6/km2) than small forests (2.4/km2). Small forests produced more fruit/ha per month but lacked a number of important hornbill food species. Monthly fruit availability in large and small forest fragments had no significant effect on fluctuations in hornbill density. However, hornbill densities were significantly higher in forests with high densities of strangling figs, after controlling for patch size, and in larger forests hornbill densities correlated with the abundance of ripe figs. We hypothesize that small patches still have conservation value if they are within hornbill ranging distance, and speculate that Sumba's forests are in a dynamic phase before the full impact of fragmentation has been expressed.

Habitat loss and degradation are critical threats for the globally threatened White-naped Crane Grus vipio. We estimated the size of the area used per day and the time budgets of parental and non-parental White-naped Crane pairs in north-eastern Mongolia during 2000 and 2001. Six parental crane pairs used an area of 11–155 ha per day. The maximum distance of a focal parental crane from the roosting-site was 3,030 m. Habitat conservation measures for breeding White-naped Cranes need to be targeted to within at least 3 km of the roosting-site or nest-site. Parental cranes spent 79.6 ± 4.8% of the daylight period foraging and had reduced preening and resting behaviour to 4.4 ± 1.9%. Pairs without juveniles showed a pronounced period of resting and preening behaviour during midday, which was absent in parental cranes. This indicates that parental cranes may be time-stressed. We conclude that increases in feeding-related activities (e.g. caused by a decrease in food availability) are likely to be at the expense of parental vigilance. Conversely, increases in vigilance (due to e.g. increased disturbance) may have a negative impact on feeding-related activities. Both increases can potentially negatively affect reproductive success in this Vulnerable species.

The largely deforested island of Cebu, Philippines, hosts a forest-dwelling hawk-owl identified in the literature as Ninox philippensis spilonota but which is in fact a Cebu island endemic species, soon to be named. To determine the current distribution and habitat requirements of this hawk-owl, the five largest of 11 remaining forest patches on Cebu were surveyed between March and June 2011, involving 64 post-sunset 500-m walked transects with playback and habitat assessments. Radio-telemetry studies were also conducted on 10 owls but only for 3–5 days per owl as they removed the transmitters. A total of 52 owls were located across all five forests (at 16 sites two owls responded together to playback) but only the largest forest, Alcoy, contained enough transects for analyses of habitat in relation to owl distribution. Alcoy stands on steep-sided hills and some planting of exotic species occurs within it. Owls were detected in forest interior, forest edge and forest-plantation mix in Alcoy, and on ridges and in gullies despite lower tree densities and greater proximity to clearings in the gullies. However, parts of Alcoy experience strong winds, and owl occupancy decreased significantly with increasing wind speed. Home ranges for the 10 radio-tagged owls were estimated to cover ∼10 ha, although given the short tracking periods this may be an underestimate. Suitable forest studied covers roughly 1,670 ha, with six unstudied forests totalling 250 ha, so assuming a pair every 10 ha would give a tentative global population estimate of ∼ 200 pairs of Cebu Hawk-owls, and even fewer if home ranges are larger than estimated. This, coupled with continuing habitat degradation, triggers the IUCN Red List category ‘Endangered’. Tree cavities suitable for nests may be limiting, and nest-box provision could be explored, provided this does not increase predator pressure on other rare species.

Swainson’s Warbler Limnothlypis swainsonii is a secretive species of high conservation concern with an estimated global breeding population of 90,000 individuals sparsely distributed across 15 states in the south-eastern United States. Its status as one of the rarest songbirds in North America has been attributed to the scarcity of breeding and wintering habitat. Although the warbler was once thought to be a habitat specialist of lowland canebrakes, it is now known to breed in a wide spectrum of broadleaf forest habitats linked by the common denominator of high stem densities and visual screening in the understorey stratum. Scattered instances of a fundamental habitat expansion into early seral stages of even-aged pine plantations were first observed in east Texas in 1992. Here I report that the colonisation of pine plantations is not only locally extensive in Texas but that it is widespread on the coastal plain eastward to south-eastern Virginia. During two decades of field surveys, breeding territories (n = 297) were documented in young pine plantations in 95 counties and parishes in 10 states. Occupied plantations were mostly 6–12 m tall (median = 7.5 m), corresponding to 8–15 years after planting. Soil type and the presence of interspersed broadleaf vegetation may be important co-factors in plantation occupancy. The chronology of this breeding niche expansion is poorly known but it appears to have occurred after the 1970s, most likely catalysed by the rapid growth of pine plantation silviculture after World War II. As late as 2001, it was believed that > 90% of the breeding population occurred in broadleaf floodplain forest. The recent range-wide colonisation of pine plantations changes the calculus. If the current trend continues, forest lands managed for short-rotation pine plantations will support the majority of breeding populations by the end of the 21st century.

Since 2010, Jankowski’s Bunting Emberiza jankowskii has been listed as ‘Endangered’ on the IUCN Red List of Threatened Species. However, because no comprehensive surveys had been conducted, it was not known whether undiscovered populations existed elsewhere, so the population status of the species could not be assessed accurately. The aim of this study was to assess the breeding distribution and population size of Jankowski’s Bunting in China. Fifty sites in Inner Mongolia, and Jilin, Heilongjiang, Liaoning and Hebei Provinces were surveyed to locate suitable habitat and breeding populations of Jankowski’s Bunting. The surveyed sites included historical breeding distribution areas, wintering sites, and regions adjacent to historical breeding distribution areas. We confirmed that Jankowski’s Bunting has disappeared from most of its former breeding distributions, with the exceptions of Dagang, Xiergen and Tumiji. Additionally, 13 new breeding sites were discovered in Inner Mongolia. All currently known populations breed in Mongolian steppe-vegetation zones, with shrubs dominated by the natural Siberian apricot Prunus sibirica, indicating that this type of habitat is crucial for the survival of the species. Based on remote sensing, the suitable breeding habitat for Jankowski’s Bunting is estimated to be approximately 280 km2. The population size of Jankowski’s Bunting could range between 9,800 and 12,500 individuals, which is much higher than the numbers estimated in previous reports that were based on partial surveys. The suitable habitat remaining in Inner Mongolia would highly benefit from the implementation of the National Key Public Forest Protection Project. The population size of Jankowski’s Bunting is larger than previously estimated, but it is still threatened by habitat degradation and fragmentation, and our survey results reinforce the need for more research. The status of Jankowski’s Bunting in China still meets the IUCN criteria B2ab for an ‘Endangered’ species.

Spix's Macaw Cyanopsitta spixii has always been a very poorly known species from the arid interior of north-east Brazil. Previous views that its habitat is buriti palm swamp appear mistaken, as the most recent field observations and the testimony of local people suggest that Tabebuia caraiba gallery woodland along seasonal creeks is a critical habitat component. Owing to widespread destruction of such woodland, during a survey in June/July 1990 only three good patches were found, all failing to regenerate; one held a single bird, and another held birds up to last year.

A Ararinha-azul Cyanopsitta spixii sempre foi uma espécie pouco conhecida no interior árido do nordeste do Brasil. Opiniōes anteriores que o seu habitat é buritizais parecem erradas porque as observações de campo mais recentes e o testimônio dos habitantes locais sugestem que matas de Tabebuia caraiba ao longo de riachos estacionais são um crítico componente do habitat. Devido à destruição extensa deste tipo de mata, durante um levantamento em junho/julho 1990 somente tres áreas boas foram achadas, todas sem regeneração; uma abrigava um único pássaro, e uma outra abrigava pássaros até o ano passado.

In this study I present data suggesting altitudinal movements of some species of foliage-gleaning insectivorous birds and related species of an oak-pine woodland of western Mexico. These movements can be regarded as short-distance or local migrations because the species involved breed in the woodlands and forests of the Sierra Madre Occidental highlands and winter in the tropical forests of the Pacific lowlands. Nine species of insectivorous birds out of 17 breed at the study site in the mountains of southern Durango and move to the lowlands in the winter; these can be regarded as short-distance or local migrants. In Mexico tropical deciduous and semi-deciduous forests are distributed mostly in the Pacific lowlands in the states of Sinaloa, Durango, Nayarit and Jalisco. Tropical forests of the Pacific lowlands are very important as wintering grounds for both North American and local west-Mexican migrants; however, there is only one protected area in western Mexico which to some degree includes these two types of tropical forests, and it is not located in the Sierra Madre Occidental, the most important mountain range in Mexico in terms of length and area covered. In addition, these tropical forests are the northern limit of the range for many tropical species. At present, these habitats are not threatened seriously by human activities (mainly forestry and cattle-raising) but this might change at any moment. At the study site the temperate highlands of southern Durango are already under the protection of “La Michilía” Biosphere Reserve, but a proposal to enlarge the area of the reserve to include the valley of the Río Mezquital and the western slope of the valley will increase the diversity of habitats, both temperate and tropical. As a consequence more bird species, as well as other taxa, will be protected in their natural environments. Such a proposal must be supported by field evidence on actual habitat use both during the breeding and wintering season, by local and long-distance migrants, in order to assess accurately the importance of this area as a representative place of western Mexico.

The Maleo Macrocephalon Maleo is a megapode bird endemic to Sulawesi, Indonesia, that lays large eggs at communal nesting grounds in naturally-heated sands or soils. It is classified as ‘Endangered’ and many populations have been extirpated due to overexploitation of eggs and loss of connectivity between forest and nesting grounds. The distribution and status of nesting grounds across Northern and Central Sulawesi are relatively well-established, but almost nothing is known about potential Maleo populations of South-east Sulawesi. In this study we used previously established methods to formally assess the status of three Maleo nesting grounds in Buton, South-east Sulawesi, and interviewed egg collectors at these three sites to determine the trends of populations and threats over time. All nesting grounds were severely threatened and can be expected to be abandoned in the near future due to extensive harvest of eggs and deforestation. Eggs were collected both for the wildlife trade (intensively harvested and sold as luxury items to people from distant cities) and local use (opportunistically harvested and both eaten and sold locally). All egg collectors remarked on an increase in illegal logging around nesting grounds over the previous decade. Though the Maleo’s current situation is dire, previous case studies show that collaborative grassroots initiatives supported by government and NGOs can protect nesting grounds and reverse population declines.

Determining the efficacy of using indicator species to predict the spatial location of biodiversity hotspots is one way of maximising the conservation of biodiversity in already threatened habitats. Recent evidence from Europe suggests raptors can play such an indicator role, so we tested this approach with a globally threatened southern hemisphere species, the Black Harrier Circus maurus. We asked if this species, found in South Africa’s mega-diverse Cape Floral Kingdom, breeds in habitat fragments that were more diverse in terms of small mammals, birds and plants than unoccupied fragments of similar size. Renosterveld is a highly fragmented habitat that has lost > 90% of its original extent and remains only on privately-owned lands. Surveys of small mammals, birds and plants undertaken in 20 fragments in the Overberg region, South Africa, revealed nine with breeding harriers and 11 without harriers. Harrier-occupied fragments were associated with a 3.5 fold higher number of bird species and higher small mammal species richness than unoccupied ones. There was a lower abundance of most plants in occupied patches, except for red grass Themeda triandra which is an indicator of pristine renosterveld. Vegetation structure was significantly different, with harriers nesting on patches with taller, more open vegetation. While the diversity trends were not statistically significant, a positive trend between the presence of harriers and higher abundance of red grass – as an indicator of the more pristine state of the patch, suggests that harriers might allow biodiversity managers a heuristic approach for selecting the remaining patches of pristine renosterveld. The need for intensive sampling of several taxa leads to small samples and a lack of clear-cut trends for these top predators as indicators of plant diversity.

Since the mid-1980s, exhausted pastures in Ecuador have been increasingly abandoned, allowing forest regeneration. At approximately 2,200 m in the Tandayapa valley I surveyed four abandoned pastures to evaluate their use by birds. Each former pasture represented a different age of vegetation maturity. The number of bird species recorded in each successively older abandoned pasture increased but only half the number of species recorded in the undisturbed forest site was recorded in the most mature pasture. However, at least four restricted-range bird species were recorded in a single pasture. As pastures rapidly convert to secondary forest, more bird species and rarer bird species use them, even in highly disturbed areas where surrounding pristine forest constitutes less than 10% of local forest cover. Conservation efforts should then be directed toward them.

Searches were made for the Colombian Grebe Podiceps andinus in 1981 in the wetlands in the Eastern Andes of Colombia. The studies also included surveys of other waterbirds and recorded the general conditions of these wetlands, once the stronghold for waterbirds in the northern Andes. The Colombian Grebe was apparently last seen in 1977 in Lake Tota, and is probably extinct, although a flock may have been moving around outside Lake Tota and could have settled outside the former breeding area. The primary reason for the decline must be draining of wetlands and eutrophication and siltation which destroyed the open submergent Potamogeton vegetation, where this grebe may have been feeding on a large diversity of arthropods. Introduction of exotic fish and hunting may also have played a role.

Durante 1981 se han realizado varias expedidones en busca de Podiceps andinus en las zonas húmedas de los Andes Orientales de Colombia. Durante estos estudios también se censaron otras aves acuáticas y se tomaron notas sobre el estado general de éstas zonas húmedas, que en el pasado fueron el principal enclave para las aves acuáticas en los Andes del Norte. Aparentemente Podiceps andinus fué visto por última vez en 1977 en el Lago Tota, y está probablemente extinguido, aunque podría haber un bando en las inmediaciones de dicho lago que se hay a establecido fuera de la antigua área de cría. La razón fundamental del declive debe ser el drenaje de las zonas húmedas y la eutrofización y salinización que ha destruido la vegetatión sumergida de Potamogeton, donde ésta especie se alimentaba de una gran variedad de artrópodos. La introducción de peces exóticos y la caza pueden haber influido también.

Cercomacra carbonaria and Synallaxis kollari are passerine birds endemic to the gallery forests of Roraima state in northernmost Brazil and adjacent Guyana. The IUCN Red List of Threatened Species lists both as Vulnerable but they have been removed from Brazil's list of threatened species because of data deficiency. They are poorly known, reflecting both Roraima state's distance from Brazil's main population centres and the inaccessibility of their habitat. In 2004 and 2005, we conducted bird surveys along the major rivers that provided previous sightings, and expanded records from only a handful to several dozens. We found C. carbonaria at 29% of the points surveyed, and estimated its local population density at approximately 80 individuals km−2 and total population size to exceed 15,000 individuals. The species has 723 km2 of available habitat, 8% of which is inside conservation units. We found S. kollari at 44% of the points surveyed, and estimated its local population density as approximately 60 individuals km−2, with an estimated total population size exceeding 5,000 individuals. It has 206 km2 of available habitat, none of which is inside conservation units. We recommend that C. carbonaria be down-listed on the IUCN Red List to the Near Threatened category, and that S. kollari be listed as Endangered. Both species live in areas vulnerable to habitat loss. We also recommend that both species re-enter the Brazilian list of threatened species and highlight the importance of indigenous reserves to their conservation.

Resumo

Cercomacra carbonaria e Synallaxis kollari são aves passeriformes das matas de galeria do Estado de Roraima em sua parte mais ao norte do Brasil e da Guiana adjacente. Ambas as espécies são catalogadas como “Vulneráveis” pela lista vermelha de espécies ameaçadas da IUCN, mas foram excluídas da lista de espécies ameaçadas do Brasil devido è insuficiência de dados. Estas espécies são pouco conhecidas, refletindo tanto a distância do Estado de Roraima dos principais centros urbanos quanto a inacessibilidade do seu hábitat. Em 2004 e 2005, realizamos censos de aves anteriormente avistadas ao longo de rios maiores, aumentando assim os registros de apenas alguns poucos números para diversas dezenas. Encontramos C. carbonaria em 29% dos pontos amostrados e estimamos sua densidade local em ∼80 indivíduos km−2 e o tamanho populacional total em mais de 15.000 indivíduos. A espécie possui 723 km2 de habitat disponível, 8% do qual está incluído em unidades de conservação. Encontramos S. kollari em 44% dos pontos amostrados e estimamos sua densidade populacional local em ∼60 indivíduos km−2, com uma estimativa de tamanho populacional total em mais de 5,000 indivíduos. Esta espécie tem 206 km2 de habitat disponível, nenhum dos quais incluído em unidades de conservação. Recomendamos que C. carbonaria seja rebaixada para a categoria ‘Quase Ameaçada’ e S. kollari categorizada como ‘Ameaçada’ na lista vermelha da IUCN. Ambas as espécies vivem em áreas vulneráveis em relação è perda de seu hábitat. Recomendamos, também, que ambas as espécies sejam re-incluídas na lista de espécies ameaçadas do Brasil, destacando a importância das reservas indígenas para a sua conservação.

Gull-billed Tern Gelochelidon nilotica is classed as Endangered in Europe (Tucker and Heath 1994, Hagemeijer and Blair, 1997), but there have been no detailed studies of the trends in the different populations occurring in Europe and Africa. Here we study the status and trends of the species in Europe and north and north-east Africa. We estimate the total population at 10,500–12,900 breeding pairs, and recognize two biogeographical populations in this region. The western population, comprising colonies in northern Europe (Denmark, Netherlands, Germany), France, Italy, Spain, and north and north-east Africa, consists of at most 6,200 pairs, 1,800 of which are in African colonies. The eastern population, comprising colonies in the Balkan Peninsula, Greece, shores of the Black Sea and Sea of Azov, and Turkey, consists of at most 6,800 pairs. Two trends were observed: a first phase from 1900 up to the mid-1970s in which the northern European populations practically disappeared; and a second phase of stabilization, or even increase, in some of the western colonies, while the eastern population continued to decline. There is a marked concentration of the species in just a few localities in the countries of the Mediterranean basin.

Safeguarding threatened species in captivity is a promising management approach, but evaluating the performance of captive programmes is essential to assess reintroduction potential. The eastern population of the Northern Bald Ibis, Geronticus eremita, used to be a locally common migratory bird species, but catastrophic population declines throughout the past century have resulted in a single population in southern Turkey that forages freely during summer but only survives in captivity during winter. We examined whether breeding success of this semi-wild colony was comparable to breeding success of previous wild populations, and to what extent breeding success was influenced by supplementary feeding and wild foraging in habitats near the breeding station. Average productivity from 2009 to 2015 was 1.12 fledglings per nesting pair (range 0.96–1.19). In 2013 and 2014, there was no correlation between attendance at supplementary feeding events and productivity, and breeding birds attended on average only 35% of supplementary feeding events. Birds that were frequently observed at a local tree nursery raised fewer offspring, while birds observed more frequently in poldered cultivation, and in particular in mint crops or in fields covered with manure, raised on average more offspring. Foraging success was highest in meadows and cropland, particularly in mint crops and fields covered in manure, and lowest at the tree nursery. We speculate that selection of highly suitable wild foraging habitat such as mint crops or fields covered in manure allows the Northern Bald Ibis to raise more fledglings than exclusive reliance on supplementary food provided at the breeding station. Establishing a second breeding colony of this species in Turkey will therefore require a careful assessment of the suitability of wild foraging habitat in the vicinity of suitable nesting opportunities.

Many South American hotspots of bird endemism are found in Polylepis dominated forests. Although the avifauna of Polylepis forests has been relatively well studied in the tropical Andes, little is known in Argentina. In this study, we characterize the Argentine avifauna of Polylepis australis forests along their entire latitudinal gradient of distribution and provide a first systematic bird list and their conservation status. Fieldwork was carried out from 1,500 to 2,800 m a.s.l. in three study sites: North (Jujuy province), Centre (Tucumán province) and South (Córdoba province); we surveyed 30 point counts per site. We recorded 543 individuals belonging to 50 bird species; two subspecies are endemic to the South site and four species are typical Polylepis forest birds of the North and Centre sites. We identified four species of conservation concern; one globally threatened and three declining at regional level. Bird richness and abundance decreased with latitude; and equitability showed an inverse pattern. Sorenson's similarity index ranged from 12% to 40% showing a large latitudinal turnover in avian communities. Disturbance-sensitive species were the most diverse group in the North site. Variations in species richness, evenness and guild composition may be a response to latitude, but also to differences in habitat complexity and food availability, which appear to be a consequence of forest degradation at the South site. We recommend: (1) the enlargement of Calilegua National Park to include the Polylepis australis belt to assure the conservation of many disturbance-sensitive species which could decline or disappear in degraded areas; (2) management of Quebrada del Condorito National Park to increase the forest structure complexity and therefore provide habitat for disturbance-sensitive species.

The Little Bustard Tetrax tetrax is a Near Threatened grassland bird that is fully migratory within its eastern population, wintering in large numbers across the south Caucasus and northern parts of Iran. The species’ habitat selection has been comprehensively studied in its western European range, but very limited information is available for its eastern population. Surveys carried out between 2010 and 2015 show a considerable population increase and probable range expansion in the region. We modelled the suitability of potential winter habitat for the species and found that distance to country border, land cover and altitude were the most important variables in predicting habitat suitability. There is still considerable hunting pressure in Iran and distance to border is likely to be related to strict hunting prohibition along the border belt imposed for military purposes. This represents an opportunity for the conservation of the species, where management efforts should aim at ensuring the maintenance of suitable land cover.

Modelling the distribution of species of conservation concern is an important issue in population ecology. Classically, logistic regression analyses are conducted to estimate species’ distributions from detection/non-detection data in a sample of sites and to test for the significance of several environmental variables in predicting the probability of occurrence. These modelling approaches assume that species detection probability is constant and equals one in all sampled sites, which is critical, notably in the case of rare, shy and cryptic species. The capture-recapture-like approach developed by Mackenzie et al. (2002, 2003) provides a reliable tool that accounts for imperfect detection when estimating species occurrence, as well as for assessing the relevance of site features as predictors of species occurrence probability. The aim of this study was to explore the possibility of using this approach in the context of Houbara Bustard Chlamydotis undulata in southern Tunisia. Our results show once more the low detectability of this emblematic species and stress the need to take this factor into account when estimating Houbara spatial distribution. The distribution of Houbara in southern Tunisia is more likely to be shaped by human-related than by habitat factors. In particular, Houbara occurrence was positively associated with site remoteness and camel numbers. Houbara seemed to avoid areas with high human presence and shared the most remote and agriculture-free zones with free-ranging camels.