The urgent global objective of developing sustainable tropical forestry management practices, which also target biodiversity conservation, requires rapid comparative studies that address both biogeography and logging practices. This paper examines avifaunal implications (focusing on species diversity and composition) of forest fragmentation and selective logging, by comparing 15 selected reserved forests in south-west Ghana. The regeneration time since last logging varied from 0 (logging continuing) to 21 years, with one unlogged site as control. Extraction levels ranged between 0.20 and 3.75 trees per ha (mean 0.90). Bird sampling involved understorey mist-netting and standardized line-transect walks, which respectively accumulated 8,348 captures and 22,452 single records of 147 species. Mist-net data showed that understorey bird diversity was positively correlated with logging intensity up to c. 3 trees per ha, reflecting increased influx of open-land species and a persistence of forest obligates during the first 5 years after logging. The overall abundance of forest interior species tended to decrease 5–10 years after logging, but recovered fairly well thereafter. Canopy birds were generally more logging-resilient. Rare forest obligates with high conservation importance were found to be equally abundant in virgin and logged, large forests, whereas these birds were poorly represented in small heavily logged forests. The results are compared with findings from other regions, and conservation implications and constraints are discussed in a global perspective. Finally, recommendations on size-related sustainable extraction levels and regeneration time are presented for the Upper Guinea Forest.

Post-fledging survival plays a vital role in the dynamics of bird populations and yet is the least-studied avian life-stage. Habitat requirements post-fledging may have important implications for behaviour and survival, especially for declining populations in landscapes that have undergone wide-scale anthropogenic modification, resulting in an altered distribution and composition of habitats. The European Turtle Dove is a widespread but rapidly declining species both within the UK and across Europe. Reduced seed food availability is thought to influence breeding success of this species, but it is not known whether post-fledging survival may also be influenced by seed availability. Here, we use leg-ring radio-tag attachments to monitor post-fledging survival and movements in 15 Turtle Dove nestlings from eight nests monitored during 2014 as part of a wider autecological study. Fledglings remained in close proximity to their nest for three weeks post-tagging, spending more than half their time in the immediate vicinity (within ∼20 m) of the nest. 95% of foraging trips during this period were within 329 m of the nest and fledglings selected seed-rich habitat (semi-natural grassland, low-intensity grazing, fallow and quarries). Fledglings that were heavier and in better body condition at seven days old were more likely to survive for 30 days post-fledging, and the proportion of available seed-rich habitat was a strong predictor of nestling weight and condition at seven days old. Whilst our sample size is modest, this study highlights the crucial role of food availability in juvenile survival, both while adults are feeding nestlings, and to recently fledged young, and the potential for agri-environment schemes providing foraging and nesting habitats in close proximity to provide important benefits.

The Montserrat Oriole Icterus oberi is endemic to the Caribbean island of Montserrat where, prior to 1995, it was widely distributed across the island's three main interior mountain ranges: the Centre, Soufriere and South Soufriere Hills. In July 1995, a long-dormant volcano on Chances Peak in the Soufriere Hills began to erupt. Since then the forest habitat of the oriole on the Soufriere and South Soufriere Hills has been devastated by pyroclastic flows and surges, heavy ash eruptions and rock falls. The Montserrat Oriole populations that inhabited these two mountain ranges have probably been lost. In December 1997, a census of the remaining Centre Hills population was undertaken to assess its status in the face of the heavy ash fall that occurred earlier the same year. To do this, a systematic grid of 140 sample points was overlaid on an area of 1,437.5 n a encompassing the Centre Hills, and a 10-minute count of all bird species was undertaken at 137 of these points during an eight-day survey period. The distance from the point to each oriole detected was measured and records of all other species were allocated to one of five distance bands radiating out from the point. Distance sampling was used to model densities, and thus to estimate population sizes, of eight bird species in the study area. It was estimated that 4,000 (95% CIs 1,500–7,800) Montserrat Orioles remain in the Centre Hills and thus the world. Although the probability of pyroclastic flows and surges overrunning the Centre Hills is considered rerrtote, it is recommended that the Montserrat Oriole be classified as Globally Threatened (Endangered) under the revised IUCN threat categories because of its loss of breeding habitat since 1995.

The coastal and offshore waters of Southwest Greenland are internationally important winter quarters for seabirds. We crudely estimate a minimum of 3.5 million seabirds using the region in winter, mainly from Arctic Canada, Greenland and Svalbard, with smaller numbers also from Alaska, Iceland, mainland Norway and Russia. The most numerous species are Common Eider Somateria mollissima, King Eider S. spectabilis, Brünnich's Guillemot Uria lomvia and Little Auk Alle alle. The most immediate threat to the seabirds in Southwest Greenland is hunting, and current levels of usage of the Greenland breeding populations of Brünnich's Guillemot and Common Eider are considered unsustainable. Conservation measures are required for these populations.

A five-month study of the Red-fronted Macaw Ara rubrogenys, endemic to Bolivia, yielded a population estimate of 2,000–4,000 individuals. The species is resident and locally common in, but restricted to, an area in the drainage systems of the Rio Grande, Rio Mizque and northern Rio Pilcomayo. One-third of the population was composed of juveniles some three months after the end of the breeding season. During the dry season, with food apparently short, more of the day was spent feeding than during the wet season. Semi-deciduous vegetation along the rivers produced fruits and seeds that sustained the macaws during the dry season, but the conversion of such areas to arable land forces the macaw to depend for some months on crops and weeds. Local farmers consider the macaw a serious pest on maize.

We studied foraging habitat selection by Lesser Kestrel Falco naumanni throughout the breeding period in south-west Spain by means of transects on which foraging observations were recorded. We focused on the effects of habitat and crop type, but also on the effect of vegetation structure and the presence of agricultural activities in the field on Lesser Kestrel use. We considered both the accumulated use of the foraging area during the breeding season and the instantaneous foraging habitat selection by kestrels. Foraging habitat selection was highly dynamic following crop development and agricultural activities. Almost all major arable crop types showed positive selection during some part of the breeding cycle. Accumulated use by kestrels demonstrated positive associations with wheat and cotton fields and negative selection of permanent habitat types, such as forested areas, woody crops and built-up areas that have no prey or are not used by the species due to unfavourable structure. Vegetation structure appears to play a major role in instantaneous foraging selection. Lesser Kestrels select fields with short vegetation and intermediate cover. They also forage on field margins and where agricultural activities such as ploughing or harvesting that facilitate access to prey are being conducted. Our results help to clarify apparent controversies among previous studies on the subject, highlighting the importance of the heterogeneity of agricultural landscapes around colonies (crops at different growth stages which provide variable vegetation height and cover during the breeding cycle) and the effect that agricultural activities have on facilitating access to prey. Beyond the species-specific approach, our work encourages further studies on habitat selection by farmland birds to account not only for human-based categorisation of habitats (e.g. crop type) but also on objective measures such as vegetation height and cover that influence access to prey and better reflect the high dynamism of agricultural landscapes.

The South African Fynbos biome, a global biodiversity hotspot with high endemism and species richness, has six endemic bird species. These are important not only intrinsically, but also for ecological functioning and as flagships for South Africa’s economically valuable avitourism sector. Little is known about population sizes or realised distribution ranges of these six species, but projected range modelling based on occurrence from the South African Bird Atlas Project (SABAP) has suggested these species are vulnerable to climate change. We estimate global population sizes for these six endemics based on densities calculated from two intensive biome-wide point count surveys in 2012. We modelled regions of suitable climatic space, from which we established that mean annual temperature and the temperature of the warmest quarter of the year appear to limit Cape Rock-jumper Chaetops frenatus and Protea Canary Serinus leucopterus ranges. Both species have seen an apparent > 30% decrease in range and reporting rates (a proxy for abundance) in the twenty years between SABAP atlas periods (1987–1991 and 2007–ongoing). The Cape Rock-jumper result is unexpected: encounter rates are higher in shorter vegetation, dry slopes and habitats with more recent occurrence of fire – all proxies for proximate causes of climate change on the Fynbos. Although coastal plains are highly transformed, mountain Fynbos is the best protected of all the world’s Mediterranean-climate habitats, with relatively little anthropogenic land transformation. Long term weather datasets from the Fynbos demonstrate significant warming since 1960. We conclude from these lines of evidence that these decreases are consistent with the loss of suitable climate space and inability of these species to adjust physiologically to increasing temperatures.

Until recently, Bermuda Petrel Pterodroma cahow (IUCN Category: ‘Endangered’) bred only in sub-optimal habitat on four small islets in north-east Bermuda. Although intensive management of the population since 1962 has led to a substantial increase in population size (now approaching 100 pairs), the nesting habitat on these four islets is being increasingly inundated, eroded and destroyed by high seas associated with hurricanes and storms. To ensure the long-term conservation of the species a decision was made to establish a new colony at a more secure site on nearby Nonsuch Island, where they once bred in large numbers. Between 2004 and 2008, 104 near-fledged nestlings were translocated to artificial burrows on Nonsuch Island, where they were hand-fed meals of fish and squid. All but three translocated birds fledged successfully, with the first returning to Nonsuch Island in February 2008. The first Bermuda Petrel egg on Nonsuch Island in more than 300 years was laid in January 2009, and the resultant fledgling departed in June of the same year. By the end of the 2009/10 breeding season, a total of 18 Bermuda Petrels have been recorded on Nonsuch Island, 17 were translocated as near-fledged nestlings, and one bird came from the existing colonies. A total of five eggs have been produced, resulting in two fledglings. The establishment of this new colony, at a site that is much more secure than the existing nesting sites, greatly enhances the conservation prospects of the species and demonstrates the importance of translocation as a tool for the conservation of threatened seabirds.

The global decrease of vulture populations has been attributed to several factors, such as food availability, poisoning, human disturbance, or habitat suitability. We studied the effect of factors that vary both spatially and temporally on the nest site distribution of the Griffon Vulture Gyps fulvus in northeast Portugal, and influence the population dynamics of these cliff-dwelling birds. Several demographic parameters were studied in the field, and the age structure of the population was determined. Additionally we investigated how food availability affected population fluctuations. The vulture population was most sensitive to juvenile mortality according to our model results. Our models showed that a decrease in the present food supply resulted in a decrease in vulture abundance and, moreover, negatively affected the spatial distribution of the species by decreasing the number of breeding pairs per colony. The total quantity of sheep and goat biomass, a greater distance to the nearest unpaved road, and the presence of Egyptian Vultures Neophron percnopterus at the breeding colonies showed a significant positive relationship to the numbers of Griffon Vulture breeding pairs. It is recommended that the available food supply in the most important foraging areas should be monitored and protected. Furthermore, to manage the community of cliff breeding raptors adequately, future research should identify and protect the most suitable breeding areas for each species. Human disturbance should be kept to a minimum by protecting breeding areas, especially in an area like Riba-Côa where species such as the Egyptian Vulture, Bonelli's Eagle Hieraaetus fasciatus and Griffon Vulture breed so close to each other.

Reintroduction projects usually attempt to re-establish a self-sustaining population of endangered species within their historical ranges through the release of captive-bred individuals into the wild. We studied the breeding biology and nesting success of a reintroduced population of Crested Ibis Nipponia nippon in Ningshan County on the south slope of the Qinling Mountains of Shaannxi Province, China. From May 2007 to October 2011, 56 captive-bred individuals, composed of 26 females and 30 males, were released into the area and monitored using radio-telemetry. The average age of individuals at release was 5.2 ± 2.5 years for females and 6.4 ± 2.9 years for males. Mean clutch size was 3.14±1.06 (range 1-5). Mean number of fledglings per active nest was 1.57 ± 1.03 and mean number of fledglings per successful nest was 2.00 ± 0.87. Most of the fledglings survived to complete their post-fledging dispersal. Mean annual survival rate was 0.552 ± 0.064 for all released birds, 0.815 ± 0.054 for breeders, and 0.515 ± 0.058 for first year fledglings. The average number of young produced/year/pair was 1.57 ± 1.03 and the growth rate (λ) of the reintroduced population was 1.2193. We confirmed that starvation and predation by King Rat Snake Elaphe carinata were the main causes of death of released individuals, nestlings and fledglings. This is the first attempt to reintroduce captive-bred Crested Ibis to former natural habitat. The ability of captive-bred ibis to survive and breed successfully bodes well for future releases of this and other endangered species.

Based on an extensive literature review for the 81 species of Falconiformes (excluding vultures) that breed primarily in Central and South America, I summarize the current state of our knowledge of the biology and conservation status of these birds. Most of what is known about the diurnal raptors in the region is based on studies carried out in the southern U.S.A., the Petén of Guatemala, extreme north-eastern South America (Venezuela through the Guianas) and Chile. The least-known species are residents of primary forest, especially in the genera Accipiter, Leucoptemis and Micrastur. Nests remain undescribed for 19 species, and less than five nests have been described for an additional 12 species. No prey data are available for six species and only anecdotal data have been published for a further 25 species. Breeding behaviour is unknown for 27 species and known only anecdotally for an additional 18. The migratory habits of 28 species are poorly understood. Available data permit a reasonable assessment of the conservation status for 39 species and a well-educated guess for another 31, but any assessment for the remaining 11 would be speculation at best.

Basado en un estudio muy extensivo de la literatura para 81 especies de Falconiformes(excluyendo Cathartidae) que se aparean principalmente en Centro y Sur América, hago un resumen de nuestro conocimiento más actual de la biologia y el estado de conservación en que se encuentran estas aves. La mayor parte de la información que se tiene sobre raptores diurnos de la región está basada en estudios que fueron llevados acabo en el sur de los Estados Unidos, el Petén en Guatemala, la parte noreste de América del Sur (Venezuela hasta las Guianas) y Chile. Las especies menos conocidos son residentes de bosque primario, especialmente de los géneros Accipiter, Leucoptemis y Micrastur. Falta describir nidos para 19 especies y menos de cinco nidos han sido descritos para 12 especies adicionales. No hay informacion sobre la alimentatión para seis especies y solamente información anecdotal ha sido publicada para 25 especies adicionales. Comportamiento de apareo se desconoce para 27 especies y solamente es conocido por anécdotas par 18 especies adicionales, Las costumbres migratorias de 28 especies se conocen muy poco. Información disponible permite juzgar razonablemente el estado de conservación para 39 especies y se puede estimarlo para 31 más, pero el juzgar de los 11 que restan seria solamente especulación.

A total of 390 bird species are known to occur in the Korup National Park (KNP) and the surrounding Korup Project Area (KPA). Although the avifauna of KNP is incompletely known, it is already among the most ornithologically diverse lowland forest sites i n Africa. The avian diversity of the KPA is increased by the montane forest bird species of the Rumpi Hills Forest Reserve (RHFR) and the Nta Ali Forest Reserve (NAFR). The lowland and montane forests of the KNP/KPA are very important to the conservation of African forest birds. Four species found in the Korup area are considered globally threatened, and four are considered near-threatened. In addition, 40 species were considered for threatened status, some of which are likely future additions to the threatened list. Twelve of Korup's 36 montane forest bird species are endemic to the montane areas of western Cameroon, eastern Nigeria, and Bioko (Fernando Po). The RHFR is especially important as a refuge for montane birds because much of the montane forest elsewhere in western Cameroon has been cleared for agriculture. Breeding phenology data are provided for many lowland forest species. Additionally, this report provides information on many rarely recorded species for western Cameroon, including several species not previously documented in the region. Kemp's Longbill Macrosphenus ketnpi was recorded for the first time in Cameroon. Because it is sympatric with the Yellow Longbill M. flavicans in Korup, additional evidence now exists for the contention that M. ketnpi and M.flavicans are separate species. The Yellow-chested Apalis Apalisflavidawas also documented for the first time in Cameroon.

Colin Bibby (1948–2004) was the quintessential bird conservation biologist. Over his career, he served as lead scientist at two of the world's largest bird conservation organizations, the Royal Society for the Protection of Birds, and BirdLife International. His contributions encompassed detailed autecological studies of rare bird species such as the Dartford Warbler Sylvia undata (e.g. Bibby 1978) and Fuerteventura Stonechat Saxicola dacotiae (e.g. Bibby and Hill 1987), a sweeping synthesis of the techniques of bird conservation science (Bibby et al. 1992, 2000), and pioneering contributions in conservation planning such as the Endemic Bird Areas concept (ICBP 1992).

Information on habitat requirements and spatial ecology is vital in conservation strategies and management of particular species. Little Owl Athene noctua is a highly threatened owl species whose populations have significantly decreased or are locally extinct in many European countries. In this study we report on spatial ecology and habitat selection of Little Owls during their breeding season in an agricultural landscape and discuss key management actions for its conservation. The mean home range size of radio-tracked Little Owls, determined by the kernel method, was 0.94 ha (SD = 0.95, 0.24–2.72 ha) and 4.30 ha (SD = 3.75, 0.88–11.70 ha) for 50% and 95% home range, respectively. The smallest home ranges were recorded in April–June (incubation and nesting period) with a significant increase in July–August (fledging season). The most important foraging habitat during the entire breeding season was grassland (especially pastures) reaching 90% for all locations. Vegetation height and cover were the main factors determining habitat selection: Little Owls significantly preferred sparse and short sward vegetation patches that enabled hunting of ground-dwelling prey. Conservation efforts for Little Owls should focus on the active management of prey-rich grassland habitats in the vicinity of breeding sites.

We studied the exploitation of crab-beds and fishing grounds by Olrog's Gulls Larus atlanticus in non-breeding areas along the coast of Buenos Aires province, Argentina. During 2004 and 2005, censuses were performed in different areas of Mar Chiquita coastal lagoon and Mar del Plata harbour. Additionally, from April to August 2005 the movements of five non-breeding individuals were studied by means of radio-telemetry. At both study sites the highest numbers of Olrog's Gulls were observed between June and August. A total of 278 radio-tracked locations (from 407 samples) were registered. All the tracked individuals showed strong site fidelity, with 96% of the radio signals registered in the vicinity of the lagoon's mouth, associated with both crab-beds and areas where sport-fishing activities took place. Conservation issues in non-breeding areas should be tackled in the near future, given the conservation status of this species (Vulnerable) and the fact that each year several Olrog's Gulls are being killed because of their interaction with sport-fishing activities.

Resumo

Se estudió la utilización de cangrejales y áreas de pesca por la Gaviota de Olrog durante el periodo no reproductivo. Durante los aãos 2004 y 2005 se realizaron censos en diferentes áreas de la Laguna Costera Mar Chiquita y el Puerto Mar del Plata, Provincia de Buenos Aires, Argentina. En ambos sitios de estudio el mayor número de individuos se observó entre los meses de junio y agosto. Adicionalmente entre los meses de abril y agosto de 2005 se estudiaron los movimientos de cinco individuos no reproductores mediante el uso de radio-transmisores. De un total de 407 muestras se obtuvieron 278 localizaciones. Todos los individuos instrumentados mostraron una alta fidelidad al sitio. El 96% de las localizaciones se registraron en cercanías de la desembocadura de la laguna, asociadas a cangrejales y areas de pesca deportiva. Considerando el estatus de conservación de la Gaviota de Olrog (‘Vulnerable’) y los efectos negativos de su interacción con la pesca deportiva, programas de conservación en áreas no reproductivas deben ser implementados.

The robust assessment of conservation status increasingly requires population metrics for species that may be little-researched, with no prospect of immediate improvement, but for which citizen science atlas data may exist. We explore the potential for bird atlas data to generate population metrics of use in red data assessment, using the endemic and near-endemic birds of southern Africa. This region, defined here as South Africa, Lesotho and Swaziland, is home to a large number of endemic bird species and an active atlas project. The Southern African Bird Atlas Projects (SABAP) 1 and 2 are large-scale citizen science data sets, consisting of hundreds of thousands of bird checklists and > 10 million bird occurrence records on a grid across the subcontinent. These data contain detailed information on species’ distributions and population change. For conservationists, metrics that guide decisions on the conservation status of a species for red listing can be obtained from SABAP, including range size, range change, population change, and range connectivity (fragmentation). We present a range of conservation metrics for these bird species, focusing on population change metrics together with an associated statistical confidence metric. Population change metrics correlate with change metrics calculated from dynamic occupancy modelling for a set of 191 common species. We identify four species with neither international nor local threatened status, yet for which bird atlas data suggest alarming declines, and two species with threatened status for which our metrics suggest could be reconsidered. A standardised approach to deciding the conservation status of a species is useful so that charismatic or flagship species do not receive disproportionate attention, although ultimately conservation status of any species must always be a consultative process.

There is a clear need for protection of the migration and wintering grounds of the Globally Threatened Aquatic Warbler Acrocephalus paludicola, but little is known about them and the threats they face. To narrow this gap, a desk study was performed between May 1998 and October 2004. Information on known wintering grounds was sought by means of questionnaires, personal communications, ringing data, publication and internet searches. Results show that the Aquatic Warbler has so far been recorded in nine African countries, but with recent records since 1980 from only five countries (Egypt, Ghana, Mauritania, Morocco and Senegal). All present data suggest that the Aquatic Warbler migrates through north-west Africa in autumn and spring, with the wintering grounds limited to wetlands of western sub-Saharan Africa, with verified records only from Mauritania, Mali, Senegal and Ghana during the months of August to April. The species was almost always found in habitats similar to that of its breeding grounds, i.e. in Carex, Juncus or Phragmites (sedge, rush and reed) associations, but also in dense grasses, shrubs and other vegetation found in freshwater marshes, flooded or wet meadows, and along the edges of backwaters, flood basins, lagoons, lakes, ponds, rivers and wadis. Recent research suggests that at least some Aquatic Warblers may actually winter further south than the present data suggest, in countries such as The Gambia, Guinea-Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo and Benin, or maybe even in so far unexplored wetlands in Central or East Africa. Because wetlands throughout Africa face imminent threats from agricultural and tourist development, more fieldwork is urgently needed to further pinpoint the migration and wintering grounds of the Aquatic Warbler.

Populations of Gouldian Finch Erythrura gouldiae, an estrildid endemic to northern Australia, declined markedly during the last two or three decades. A survey revealed the species in two areas of Northern Territory, with an estimated 2,000 individuals, including juveniles. Recaptures were low either because of mortality or dispersal. Gouldian Finches eat predominantly Sorghum spp. seeds, but consume other seeds before Sorghum ripens. Other finches declined as cattle increased. Gouldian Finches breed in tree hollows of predominantly two species of eucalypts that grow on rocky slopes. They require water within about 4 km of the nest site. There was no shortage of nesting hollows at the known breeding sites. Fires in the early to mid-dry season allow birds access to seed without damaging trees, but later fires can destroy trees with nest hollows and remove shade. Average clutch-size is 5.2. About 72% of eggs laid, and 63% of nests, fledged young. Pairs lay up to three clutches in a season (February-August), the length of which may depend on rainfall during the preceding wet season. Air-sac mite (Sternostoma tracheacolum), found in 62% of Gouldian Finches sampled, may be preventing the species recovering to former numbers. New colonies of Gouldian Finches should be identified, populations monitored, and habitat managed by effecting patchy burns by low-intensity fires early in the dry season.

Investigating habitat selection is a key step in improving the population conservation of forest species in areas managed for different purposes, from timber harvesting to hunting or recreation. Because economic resources allocated to conservation are limited, studies that assess cost-effective strategies are necessary, especially when concerning non-threatened species. We studied nest-site habitat selection of two raptor communities (totalling 245 nests from the five most common species: Short-Toed Eagle Circaetus gallicus, Goshawk Accipiter gentilis, Sparrowhawk A. nisus, Common Buzzard Buteo buteo and Booted Eagle Aquila pennata) in two pinewoods in central Spain separated by 200 km. Using a Generalised Linear Mixed Model for each species and with locality as a random factor, we obtained five models of habitat selection. We highlighted the common nesting patterns in order to facilitate an integrated management of forestry in relation to raptor nesting habitat selection. The most important variable for all species, with the exception of the Sparrowhawk was the nest-tree diameter at breast height, with raptors preferentially selecting nesting trees of large width. Tall trees and a high amount of tree cover around the nesting tree were also important habitat features for several species. Our results suggest that pinewoods should retain unharvested patches with moderate tree coverage (30–70%) containing not only several large trees (diameter at breast height > 40 cm) but also small ones. At the landscape level, open forests and heterogeneous habitats are preferred. These forest patches should be dispersed throughout the landscape.

We estimated the present population size of the Hooded Grebe Podiceps gallardoi and compared it with the population in 1985. During the breeding seasons 2009/2010 and 2010/2011 we monitored 251 lakes on the main plateaus of Santa Cruz province, southern Patagonia, Argentina, where the entire population of Hooded Grebes spends the breeding season. During 2009/2010 we monitored 131 lakes and observed 521 Hooded Grebes in 16 lakes, while during 2010/2011 we monitored 186 lakes and observed 535 individuals in 14 lakes. At both breeding seasons five lakes contained near 85% of the population. We only observed 6 breeding colonies, two in 2009/2010 and four in 2010/2011, totalling 242 nesting attempts. Nearly 90% of the nests failed during egg stage, mainly due to strong winds and depredation by American mink Neovison vison. Only 28 nests hatched chicks, but none of the young survived to independence due to low temperatures. We compared the results of our 2010/2011 survey with one conducted during 1984/1985 and detected that the population diminished by approximately 80%. This decline was observed on all but one plateau (“Buenos Aires”) where most breeding attempts occurred. Our results show that at present Hooded Grebes are highly dependent on a few suitable lakes where they congregate to breed. We analyse possible causes for the decline of the population and propose conservation actions to protect this species.