Showing papers in "Bird Conservation International in 2013"
TL;DR: Brazil’s rich biological and cultural diversity makes it an exceptional location for examining the commerce in live wild birds and its implications for conservation, but there is an urgent need for actions that can control these activities.
Abstract: Brazil’s rich biological and cultural diversity makes it an exceptional location for examining the commerce in live wild birds and its implications for conservation. This paper catalogues the live bird species being traded in Brazil, characterises the trade in these animals, and discusses the implications for avian conservation. In spite of being illegal, capturing and selling birds is still a very common practice in Brazil and involves many actors who make up part of a large commercial network that distributes wild animals to every corner of the country. Our survey revealed that at least 295 bird species are illegally sold as pets in Brazil, with estimates derived from this data pointing to a total of more than 400 species - about 23% of the number of extant bird species in the country. Of the bird species recorded, two were classified as “Critically Endangered”, nine as “Endangered”, six as “Vulnerable”, and 19 as “Near Threatened” according to the most recent IUCN Red List. Most of the species recorded in this study as being widely bought and sold (including on the international market) are not listed by CITES even though many of them are in fact threatened. In light of the widespread illegal trade in wild birds in Brazil and the conservation implications for the species involved, there is an urgent need for actions that can control these activities. Steps should be taken to address the illegal traffic directly and these must include monitoring, law enforcement, effective sentencing (including deterrent sentences), targeting end-users, captive breeding, and education at all levels, taking into account the cultural, economic, social, and ecological aspects of the human populations involved.
146 citations
TL;DR: In this paper, a power line in Sudan continues to cause mortality of Egyptian Vultures Neophron percnopterus, a problem that was first identified in 1984, and the authors suggest that this power line may have caused the death of sufficient number of birds to partially explain population declines in the Middle East, where the electrocuted birds may originate.
Abstract: Electrocution on poorly designed power poles is increasingly shown to pose a threat for the populations of many large raptors. Here we document that a power line in Sudan continues to cause mortality of Egyptian Vultures Neophron percnopterus, a problem that was first identified in 1984. We suggest that this power line may have caused the death of sufficient Egyptian Vultures to partially explain population declines in the Middle East, from where the electrocuted birds may originate. This report highlights the urgent need to plan and retro-fit power lines in Africa with non-lethal support structures.
86 citations
TL;DR: Wang et al. as mentioned in this paper analyzed the development of birdwatching in mainland China and its roles in bird study and conservation using a standard questionnaire and interviews, and predicted that with the continued development of China's economy, birdwatching will further develop and play an increasing role in China's conservation policies and practices.
Abstract: Summary Birdwatching is a popular activity in western countries where it has helped to integrate research into birds, bird conservation, and socio-economic development. We analysed the development of birdwatching in mainland China and its roles in bird study and conservation using a standard questionnaire and interviews. Birdwatching in mainland China began only recently (in the 1990s). The increased numbers of foreign birdwatchers visiting China promoted birdwatching there. As of 2010, a total of 36 local birdwatching societies had been established, and the number of birdwatchers exceeds 20,000. The development of birdwatching has been positively correlated with local economic conditions–that is, the number of birdwatchers is much greater in economically developed areas than in relatively undeveloped areas. Birdwatchers have not only contributed to a greater understanding of the population status of birds in China but also promoted bird conservation at the local level. Although China’s conservation policies are currently formulated and implemented in a top-down manner via government regulation, with little contribution from local individuals, the rapid development of birdwatching reflects an improved understanding of conservation by local communities and growing participation in conservation initiatives by local people and organisations. We predict that with the continued development of China’s economy, birdwatching will further develop and play an increasing role in China’s conservation policies and practices. This is important as China is a country with a high rate of endemism and many globally-threatened species
57 citations
TL;DR: In this article, the responses of migratory and wintering waterbirds to five artificial wetland habitats (aquaculture ponds, paddyfields, irrigation canals, open water reservoirs and saltpans) within a novel natural-artificial wetland landscape, Yellow River Delta (YRD), eastern China from October 2007 to May 2008.
Abstract: Summary Anthropogenic conversion of natural wetlands into artificial wetland habitats has produced complex wetland landscapes worldwide. In this study we investigated the responses of migratory and wintering waterbirds to five artificial wetland habitats (aquaculture ponds, paddyfields, irrigation canals, open water reservoirs and saltpans) within a novel natural-artificial wetland landscape, Yellow River Delta (YRD), eastern China from October 2007 to May 2008. The results showed that almost all bird community indicators in the YRD natural wetlands were higher than those in adjacent artificial wetlands. Across the landscape, natural wetlands remained most important for all waterbird guilds, and more than 90% of waterbird populations were dependent on these habitats. Artificial wetlands mainly provided a secondary role, supporting about 70% of waterbird species (including six species that reached 1% of their global or biogeographical flyway populations), but with distinctive functional capacity for specific waterbird guilds in different artificial wetlands. The conservation value of artificial wetlands is often ephemeral, mainly during autumn, for specific migratory waterbirds and complements that of remaining areas of natural wetlands. Therefore, the utilisation patterns of artificial wetlands are highly temporal and the majority of species are dependent on areas of natural wetland. A comprehensive study of the inter-seasonal and inter-annual variations in these different habitats and dependence by the various guilds in the YRD is required to enable the true value of these habitats to be understood. We suggest that the conservation of artificial wetlands should not be at the expense of natural wetlands, which should remain the priority for wetland landscape management. Management to maintain the existing artificial wetlands for migrating and wintering water birds should target habitat features that are absent or limited in natural wetlands thus increasing the carrying capacity of the YRD landscape.
55 citations
TL;DR: Wang et al. as mentioned in this paper investigated bird hunting and trade in Nanmao, a remote mountainous village of Hainan Island, China, during March-July 2003 and September-October 2005.
Abstract: In China, many bird species are generally thought to be threatened mainly, or at least partly, by hunting. However, there have been few studies of bird hunting at a local scale. Bird hunting and trade in Nanmao, a remote mountainous village of Hainan Island, China, was investigated during March–July 2003 and September–October 2005. In total, 86 households were visited, of which 43% reported that they engaged in hunting of birds while 91% of households were seen to have hunted birds or hunting tools. This indicated that hunting by village people was widespread. Most hunters were male, and were between 12 and 68 years old. A total of 78 bird species were hunted, including 2 First Class and 19 Second Class national protected species. This extreme level of hunting has changed from a more moderate subsistence hunting tradition since about 1980, when local urban markets for wild meat started to develop. We outline a strategic plan designed to conserve birds, other wildlife and their forest habitats, whilst improving the livelihoods and preserving the minority tribal traditions of the people of Nanmao forest.
39 citations
TL;DR: Gough Island’s formerly abundant petrel populations are greatly threatened by the impact of predatory house mice which can only be halted by the eradication of this species from the island.
Abstract: The predatory behaviour of introduced house mice Mus musculus at Gough Island is known to impact on albatross and petrels, resulting in the Tristan Albatross Diomedea dabbenena and Atlantic Petrel Pterodroma incerta being listed as “Critically Endangered” and “Endangered”, respectively. Although predation has been documented for two burrowing petrels and one albatross species, the impact of house mice on other burrowing petrels on Gough Island is unknown. We report burrow occupancy and breeding success of Atlantic Petrels, Soft-plumaged Petrels Pterodroma mollis, Broad-billed Prions Pachyptila vittata, Grey Petrels Procellaria cinerea and Great Shearwaters Puffinus gravis. With the exception of the Great Shearwater, breeding parameters of burrowing petrels at Gough Island were very poor, with low burrow occupancy (range 4–42%) and low breeding success (0–44%) for four species, and high rates of chick mortality in Atlantic Petrel burrows. Breeding success decreased with mass, suggesting that smaller species are hardest hit, and winter-breeding species had lower breeding success than summer breeders. The results indicate that introduced house mice are having a detrimental impact on a wider range of species than previously recorded and are likely to be causing population declines among most burrowing petrels on Gough Island. The very low values of burrow occupancy recorded for Soft-plumaged Petrels and Broad-billed Prions and greatly reduced abundance of burrowing petrels in comparison to earlier decades indicate that Gough Island’s formerly abundant petrel populations are greatly threatened by the impact of predatory house mice which can only be halted by the eradication of this species from the island.
37 citations
TL;DR: A large number of raptors were electrocuted on recently erected electricity distribution lines in the open landscapes of the Mongolian steppe and Qinghai-Tibetan plateau, China as mentioned in this paper.
Abstract: We report a large number of raptors electrocuted on recently erected electricity distribution lines in the open landscapes of the Mongolian steppe and Qinghai-Tibetan plateau, China. Upland Buzzards Buteo hemilasius and Saker Falcons Falco cherrug, characteristic raptors of these bioregions, were among those found to be electrocuted. Raptor electrocution was a consequence of poorly designed hardware configurations on anchor poles along surveyed lines on the Qinghai-Tibetan Plateau and, additionally, on line poles in the Mongolian steppe. The design flaws were upright pin-insulators on earthed crossarms and the use of jump wires that passed over crossarms via pin insulators on anchor poles. Targeted mitigation of anchor poles could significantly reduce the incidence of electrocution on the lines surveyed on the Qinghai-Tibetan Plateau, whilst all poles on the lines surveyed in the Mongolian steppe require remediation to make them safe for raptors. The Mongolian steppe and the Qinghai-Tibetan Plateau are bioregions that hold the largest breeding and wintering populations of the globally threatened Saker Falcon. The existing and growing network of dangerous electricity distribution lines in these regions may potentially impact the Saker Falcon population, thus we suggest that preventative and/or mitigation measures are implemented.
34 citations
TL;DR: The biology and distribution of the Javan Green Magpie is document based on hitherto unpublished historical data and on the own fieldwork, and a novel species delimitation test suggests that jefferyi and thalassina deserve to be classified as biological species because their phenotypic divergence exceeds that found in many sympatric species.
Abstract: The Short-tailed Green Magpie Cissa thalassina, a member of an Asian lineage of uniquely coloured corvids, is represented by two subspecies, thalassina and jefferyi, that occur on the islands of Java and Borneo, respectively. The distinct Javan nominate form is poorly described in the literature and next to nothing is published on its biology and occurrence in the wild. We here document the biology and distribution of this taxon based on hitherto unpublished historical data and on our own fieldwork. We also analyse vocal data of jefferyi, thalassina and two other Cissa species and show that jefferyi and thalassina are well-differentiated, and that thalassina is bioacoustically more similar to another Cissa species from the Asian mainland. We also demonstrate important and significant biometric differences between jefferyi and thalassina that may reflect divergent adaptations to the environment, as well as plumage differences that may serve signalling functions. Finally, the application of a novel species delimitation test to our data suggests that jefferyi and thalassina deserve to be classified as biological species because their phenotypic divergence exceeds that found in many sympatric species. The revised taxonomic status of Javan thalassina invites a reconsideration of its threat status. Based on its restricted range, extreme rarity and threats by bird trapping and habitat destruction, we consider the Javan Green Magpie as globally Critically Endangered.
32 citations
TL;DR: In this paper, the authors analyzed the results of a long-term research program into Cambodian vultures that was initiated in 2004 and found that the principal causes of vulture mortality were poisoning (73%), probably as an accidental consequence of local hunting and fishing practices, and hunting or capture for traditional medicine (15%).
Abstract: Summary Asian vultures have undergone dramatic declines of 90–99% in the Indian Subcontinent, as a consequence of poisoning by veterinary use of the drug diclofenac, and are at a high risk of extinction. Cambodia supports one of the only populations of three species (White-rumped Vulture Gyps bengalensis, Slender-billed Vulture G. tenuirostris and Red-headed Vulture Sarcogyps calvus) outside of South Asia where diclofenac use is not widespread. Conservation of the Cambodian sub-populations is therefore a global priority. This study analyses the results of a long-term research programme into Cambodian vultures that was initiated in 2004. Population sizes of each species are estimated at 50–200+ individuals, ranging across an area of approximately 300 km by 250 km, including adjacent areas in Laos and Vietnam. The principal causes of vulture mortality were poisoning (73%), probably as an accidental consequence of local hunting and fishing practices, and hunting or capture for traditional medicine (15%). This represents a significant loss from such a small population of long-lived, slow breeding, species such as vultures. Cambodian vultures are severely food limited and are primarily dependent on domestic ungulate carcasses, as wild ungulate populations have been severely depleted over the past 20 years. Local people across the vulture range still follow traditional animal husbandry practices, including releasing livestock into the open deciduous dipterocarp forest areas when they are not needed for work, providing the food source. Reducing threats through limiting the use of poisons (which are also harmful for human health) and supplementary food provisioning in the short to medium-term through ‘vulture restaurants’ is critical if Cambodian vultures are to be conserved.
30 citations
TL;DR: Artificial nests can enhance African Penguin breeding success, shielding them from both predation and extreme weather events, and controlling Kelp Gulls can also enhance penguin production, especially during years of low food availability when the vulnerability of chicks to predation is exacerbated.
Abstract: Summary Drastic recent decreases in numbers of the ‘Endangered’ African Penguin Spheniscus demersus highlight the need for conservation efforts to reverse this trend. Habitat reduction due to former guano scraping forces penguins to breed in surface nests, which are vulnerable to predation by Kelp Gulls Larus dominicanus and to extreme weather events. Here I compare gull predation and the success of penguins breeding in surface nests and two types of artificial nests, before (2009) and after (2010–2011), the removal of predatory gulls from Bird Island, South Africa. Both culling gulls and providing artificial nests improved penguin chick survival, but post-culling chick survival was lower in surface nests than in artificial nests, suggesting a major impact of weather on chick mortality. Success of artificial nests was design-dependent, with poor hatching success in fibreglass burrows (probably due to high ambient temperatures), but nests under 50 cm cement pipes cut in half had the highest breeding success. Therefore, appropriately designed artificial nests can enhance African Penguin breeding success, shielding them from both predation and extreme weather events. Where implementing such nests is constrained, controlling Kelp Gulls can also enhance penguin production, especially during years of low food availability when the vulnerability of chicks to predation is exacerbated. Such a strategy would, however, require ongoing management, as territories freed by culled gulls are constantly filled with new individuals. The alarming trend in African Penguin numbers justifies robust conservation strategies, although these should also be concomitant with limiting oil spills and increasing food availability around their colonies.
26 citations
TL;DR: The maximum entropy method is used to model distribution of the rare Boreal Owl Aegolius funereus and the Black Woodpecker Dryocopus martius, which excavates the nest-holes used by the owl for breeding and can represent priority areas for the conservation of forest birds in the Alps.
Abstract: Correlative species distribution models (SDMs) are increasingly widespread in the conservation literature. They can be used for a variety of purposes, including addressing practical conservation tasks on the basis of a spatially explicit assessment of environmental suitability for target taxa, which in turn allows for a transparent evaluation of needs and opportunities. Here we used the maximum entropy method (by means of the software MaxEnt) to model distribution of the rare Boreal Owl Aegolius funereus and the Black Woodpecker Dryocopus martius, which excavates the nest-holes used by the owl for breeding. We believe that monitoring surveys for Boreal Owl should consider areas suitable for both species as priority sites, whereas the provision of nest-boxes for the owl may be particularly desirable in habitat patches that are suitable for that species but not for the keystone species whose nest-holes represent the usual nest site for the owl. Finally, areas suitable for both species can represent priority areas for the conservation of forest birds in the Alps, as both species have been reported as umbrella and/or keystone species. Our example provides a possible framework to model management and monitoring opportunities in other species or species pairs, but such an approach can be used to infer the need for particular management options when both limiting factors and species distribution can be spatially modelled, and also to model the areas where different target species are more likely to overlap and interact. The use of distribution models as tools to address practical conservation tasks should also be encouraged in order to accomplish practical tasks according to sound knowledge and transparent methods.
TL;DR: Solitary Tinamou exhibited a crepuscular pattern of activity, with most records taken at 07h00 and 06h00, and it appears to be sensitive to forest clearance.
Abstract: Solitary Tinamou Tinamus solitarius is a threatened Brazilian bird, and very little is known about its ecology and behaviour. In this study we aimed to verify the use of habitats in different stages of plant succession and the circadian activity pattern of the species. The study was conducted in Santa Catarina state (27o43’S, 48o49’W). Six camera traps were used to record the species in three areas of different successional stages during a 12-month period. Traps remained at each sample site for two months, after which they were moved to a new site, a minimum distance of 100 m apart. A total of 76 independent records of Solitary Tinamou were obtained, and its habitat use was found to be different within the three successional stages (P = 0.02). The majority of 54 independent records were obtained in the secondary forest; not one photo of the species was taken in the most degraded area. Solitary Tinamou exhibited a crepuscular pattern of activity, with most records (n = 38) taken at 07h00 and 06h00, and it appears to be sensitive to forest clearance.
TL;DR: In this paper, the authors studied woodpeckers and dead wood abundance in coniferous stands of the Bialowieza Forest, Poland, and found that woodpecker indices were highest in primeval, unmanaged stands (BNP), partially managed nature reserve (RES), and heavily managed stands (MAN).
Abstract: Many woodpecker species are known to be sensitive to the removal of dead wood. In 1999–2001 and 2007–2009 woodpeckers and dead wood abundance were studied in coniferous stands of the Bialowieza Forest, Poland. Transects (3.9–6 km long) were established in three zones of different types of management: 1) primeval, unmanaged stands (BNP); 2) partially managed nature reserve (RES); 3) heavily managed stands (MAN). Woodpeckers were counted along transects three times per season, and tree stand measurements (number of standing and fallen trees, diameter at breast height, volume of fallen logs) were made once every three years. Woodpecker indices were highest in BNP and lowest in RES in both three-year study periods. The highest number of species (seven) was recorded in RES. Indices of four woodpeckers including two focal species (Three-toed Woodpecker Picoides tridactylus and White-backed Woodpecker Dendrocopos leucotos ) were dependent on the basal area of dead standing trees. The same relation was found for the whole woodpecker assemblage. The highest indices were recorded in BNP, where the highest density of dead standing trees was recorded, and the lowest in the MAN transect with the lowest density of dead trees. However in the RES plot the amount of dead wood was much lower than in the national park. We recommend that the management regulations in Polish nature reserves be changed. In coniferous reserves, it would be best to leave at least 2 m 2 ha -1 (basal area) of freshly killed spruce Picea sp. after each bark beetle outbreak.
TL;DR: In this article, the authors assessed the potential impact of changes in future climate on the Sokoke Scops Owl using predictive niche modelling and found that the future conservation prospects of this species are bleak.
Abstract: Climate change is predicted to have serious impacts on the conservation status of numerous species of birds, particularly low-density, range-restricted species occupying narrow habitats. One such species is the globally "Endangered" Sokoke Scops Owl Otus ireneae that currently survives in just two or three small pockets of forest in coastal Kenya and north-eastern Tanzania. We assessed the potential impact of changes in future climate on this species using predictive niche modelling. Distributional data were obtained from various published and unpublished sources, and field surveys. Maximum Entropy (Maxent) was used to model the current distribution of Sokoke Scops Owl. A general circulation model was used to predict the distribution of this species in 2080. This scenario predicts a southward shift in the future distribution of this species in Kenya and a complete disappearance from the Usambara mountains in Tanzania, with a concomitant 64% reduction in areas of high environmental suitability. Considering the isolated nature of the forest fragments in which this owl survives and the sea of inhospitable human-modified habitat which surrounds these fragments, the future conservation prospects of this species are bleak. Close monitoring of the species is strongly recommended and potential conservation interventions are discussed.
TL;DR: In this paper, the authors found closed-canopy Afromontane forest with an abundance of Podocarpus latifolius and little human disturbance and recorded 89 bird species, 56 in or adjacent to forest and including all 20 priority taxa and a significant population of the Endangered Swierstra's Francolin Pternistis swierstrai.
Abstract: Afromontane forest is the most localised and threatened habitat type in Angola. For the past 40 years the estimate of the area covered by this habitat in Angola has been c.200 ha. At present, 85 ha remain at Mt Moco, the most important known site to date. This habitat holds 20 bird taxa of conservation significance but some are now rare or absent at Mt Moco. Given the small extent of forest, its high conservation value and the severe human impacts on it, finding new areas of Afromontane forest is a high conservation priority. With this objective, we visited the Namba mountains in July 2010, where c.100 ha was thought to remain in the 1970s, to establish the extent and condition of forest there and to conduct bird surveys. We found closed-canopy Afromontane forest with an abundance of Podocarpus latifolius and little human disturbance. We recorded 89 bird species, 56 in or adjacent to forest and including all 20 priority taxa and a significant population of the Endangered Swierstra’s Francolin Pternistis swierstrai. On-screen digitising of forest patches using Google Earth indicates that the larger patches are an order of magnitude larger than at Mt Moco and that there is currently > 590 ha of forest in the Namba mountains, more than trebling the previous national estimate. The site qualifies as a new Important Bird Area and is a high priority for inclusion in Angola’s protected area network.
TL;DR: In this article, the Black Harrier Circus maurus was found to breed in habitat fragments that were more diverse in terms of small mammals, birds and plants than unoccupied fragments of similar size.
Abstract: 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.
TL;DR: In the Karoo region of South Africa, eagles nesting on high voltage power pylons are responsible for frequent short-circuits or faults, which reduce the quality of commercial power supply and escalate costs to the country's energy supplier, Eskom as discussed by the authors.
Abstract: In the Karoo region of South Africa, eagles nesting on high voltage power pylons are responsible for frequent short-circuits or faults, which reduce the quality of commercial power supply and escalate costs to the country’s energy supplier, Eskom. Between 2002 and 2006 we conducted annual helicopter surveys of eagle nests on 1,400 km of power line and located 139 large nest structures, making up 96 eagle territories occupied by three species: Martial Eagle Polemaetus bellicosus (66 pairs), Verreaux’s Eagle Aquila verreauxii (13 pairs) and Tawny Eagle Aquila rapax (17 pairs), and detailed 357 pair-years of breeding activity, including 241 breeding attempts. Roost sites and active nests were associated with line faulting, and more so at particular pylon configurations. We developed a three-step management plan to reduce eagle-related faulting while still accommodating eagles on the power lines: (i) all (potentially) problematic nests were relocated from high-risk positions above the power conductors, to specially provided platforms placed below the conductors; (ii) perch deterrents were installed above the conductors on all nest pylons and on high-risk pylons up to 10 structures on both sides of each nest tower; and (iii) the welfare of the eagles was monitored before and after management. In this way, line faulting was reduced on actively managed lines by > 75%, with no obvious deleterious effects on the eagle population. The study revealed that: (i) power lines can support substantial breeding populations of threatened large raptors, (ii) these birds can be a source of commercially significant line faulting, and (iii) nest relocations and perch deterrents are effective in reducing faulting without negatively impacting eagle populations.
TL;DR: Two new inland wintering sites for the Black-faced Spoonbill Platalea minor census were discovered using satellite telemetry data, one located in China, where the individual followed the Yangtze river as far as Wuhan, and the other across the Vietnam-Cambodia border.
Abstract: In 2011 the Black-faced Spoonbill Platalea minor census recorded a 22% drop in numbers from 2010, particularly at the known large coastal wintering sites. During this period, we discovered two new inland wintering sites for the species using satellite telemetry data, one located in China, where the individual followed the Yangtze river as far as Wuhan (500 km inland), and the other across the Vietnam-Cambodia border (70–200 km inland). Long periods of concentrated use of various freshwater habitats were in evidence for these two tagged individuals (China: 79 days, Vietnam/Cambodia: 91 Days) and in the latter case visual confirmation indicated a larger group of at least five individuals. The importance and potential of inland freshwater environments is highlighted towards the further conservation of the recovering population.
TL;DR: In this paper, satellite telemetry data from four summering events belonging to three individuals breeding in two colonies in the Western Mediterranean (Spain) was analyzed, showing that all of them made inland movements in areas up to c.400 km distant from the respective breeding colonies, visiting several habitats, from forests to arable lands, probably taking advantage of high densities of insects.
Abstract: Summary Recent advances in bird tracking technologies are revealing that migratory birds use temporal staging sites other than breeding and wintering areas, and these areas deserve conservation efforts. Eleonora’s Falcon Falco eleonorae is a long-distance migratory raptor that breeds colonially on islands and is considered a priority species for conservation. Anecdotal observations indicate that during the pre-breeding period, Eleonora’s Falcons stay in inland areas far away from the colonies, but, to date there are no detailed data concerning the connectivity between these areas and breeding colonies. Using satellite telemetry, we analysed data from four summering events belonging to three individuals breeding in two colonies in the Western Mediterranean (Spain). All of them made inland movements in areas up to c.400 km distant from the respective breeding colonies, visiting several habitats, from forests to arable lands, probably taking advantage of high densities of insects. Perturbations occurring in these areas could threaten Eleonora’s Falcons with serious consequences at the population level. We suggest that conservation measures implemented at breeding and wintering grounds may not suffice and that temporary staging areas should be identified at a larger scale and deserve protection as well.
TL;DR: There is a need to maintain spatial diversity with a combination of large wetlands suitable for both species and small, vegetated ones suitable for the Marbled Teal, and to provide suitable habitat for White-headed Duck.
Abstract: Summary Understanding habitat requirements is vital for developing successful management strategies for threatened species. In this study we analyse the habitat selection of two globally threatened waterbirds (Marbled Teal Marmaronetta angustirostris and White-headed Duck Oxyura leucocephala) coexisting in an internationally important wetland (El Hondo Natural Park, south-eastern Spain) at three spatial scales. We surveyed adults and broods of these species fortnightly during two consecutive years and we related density and presence of birds to several habitat variables. At a pond-selection scale, the density of both species was related to the surface area of the ponds, with Marbled Teal showing avoidance of medium-sized ponds, and White-headed Ducks strong selection for the largest ponds. Within ponds, Marbled Teal avoided open waters, and was mainly associated with Phragmites reedbeds, but also selected areas with saltmarsh and Scirpus vegetation, especially for brood-rearing. White-headed Duck made more use of deeper areas with open water, especially in winter, and Phragmites was the only emergent vegetation with which it associated. When breeding success was very high in 2000, strong creching of broods was observed in White-headed Duck, but not in Marbled Teal. In order to provide suitable habitat for both species, there is a need to maintain spatial diversity with a combination of large wetlands suitable for both species and small, vegetated ones suitable for the Marbled Teal.
TL;DR: In this article, the authors provide an updated and more detailed account of threats faced by Olrog's Gulls at their nesting grounds, and summarise progress made towards their protection.
Abstract: Olrog’s Gull Larus atlanticus breeds only in Argentina and is currently categorized as “Vulnerable”. Knowledge of the location of colonies and an updated understanding of human activities that may impact their breeding populations are crucial to the development of adequate conservation and management actions. In this paper we update the breeding distribution and abundance of Olrog’s Gull, using information from three aerial surveys (2004, 2007 and 2009) in its main breeding area, Buenos Aires Province, complemented by additional nest counts in southern Chubut Province, covering its entire breeding range. We also provide an updated and more detailed account of threats faced by Olrog’s Gulls at their nesting grounds, and summarise progress made towards their protection. The number of breeding sites was 7–12 per year, with locations differing among years. Five previously unrecorded breeding locations were identified. Colony size ranged from 5 to 3,540 breeding pairs, with the total breeding population 4,860–7,790 pairs, 98% of which nest in southern Buenos Aires Province. The main threats faced by breeding Olrog’s Gulls include coastal development, pollution, sport fishing and unregulated tourism and recreational activities. Recent strengthening of the protected area system in Argentina has resulted in all known breeding sites, with the exception of Isla Brightman, falling within protected areas. We need comprehensive, simultaneous surveys to track global population trends. Despite enhanced protection of Olrog’s Gull breeding populations, efforts are still needed to ensure that guidelines for their protection are included in management plans and that these are implemented effectively.
TL;DR: In this article, Bald ibises spent the winter at the same site on the central Ethiopian highland plateau, from August until mid-February during five consecutive winters (2006-2011).
Abstract: The long-range, migratory eastern relict population of Northern Bald Ibis Geronticus eremita has been steadily declining since the time of discovery in 2002, despite the protection programme in place at the breeding grounds in Syria. Assessing the ecological conditions and threats along the migration route and at the wintering site, both discovered in 2006, has become a priority for this “Critically Endangered” species. Adult ibises spent the winter at the same site on the central Ethiopian highland plateau, from August until mid-February during five consecutive winters (2006-2011). The wintering site was surveyed during four field visits and assessed through a spatial analysis of 1,067 satellite locations. The site is in an agro-pastoral landscape, inhabited by a settled community of people living in relatively poor and isolated conditions. Home range analysis based on kernel distributions showed that the bald ibises used a core range area of 9.1–19.0 km² (confirmed by direct visual observations in the field) and an extended range area of 61.0–126.1 km². These figures are c.20 and 60 times smaller, respectively, than those calculated for the breeding site in Syria. Eighty-one percent of the core area in Ethiopia was used in all five years confirming the birds’ fidelity to this wintering site. Ibises preferred to forage in wet or dry pastures and in recently cut hayfields, and avoided tall grass, uncut hayfields and cultivation. Despite dependence on human-created habitats, human disturbance observed in the field was minimal. The main short-term threat for the ibises was judged to be the potential raising of attention on the part of the local community specifically towards these few individual ibises. In the medium term, the main threat comes from the conversion of pastures into crops and the potential use of fertilisers and pesticides.
TL;DR: Investigating the impact of introduced predators on the productivity of the St Helena Plover Charadrius sanctaehelenae found that nest survival varied spatially and was correlated with an index of cat density, but no relationship was observed between the number of nesting attempts per pair in a year and predator density.
Abstract: We investigated the impact of introduced predators on the productivity of the St Helena Plover Charadrius sanctaehelenae, a shorebird endemic to the South Atlantic island of St Helena. The nest predator species identified have all been introduced to St Helena in the last 510 years, and all are species that are known to be invasive on other islands. The species responsible for taking the largest proportion of eggs was the domestic cat Felis catus, with rats (Rattus rattus or R. norvegicus) and Common Myna Acridotheres tristis taking smaller proportions. Nest survival varied spatially and was correlated with an index of cat density. No relationship was observed between the number of nesting attempts per pair in a year and predator density. The resulting estimates of productivity were insufficient in some areas to allow stable populations to persist locally. Future work should focus on assessing the population level impacts of current and reduced predator densities to St Helena Plovers, and understanding the influence of resource availability and habitat structure on the densities and impacts of predators.
TL;DR: It is suggested that there is a biogeographic barrier which limits the distribution of this species in the southern part of its range and a redefinition of the current range as recognised by IUCN is proposed along with the need to change its national risk category.
Abstract: Delimiting the distribution of a species is a complex task because many determining factors are difficult to assess in the field. This is important because distribution is a key factor in the decision-making process for conservation. One example is the Bearded Wood Partridge Dendrortyx barbatus, a species endemic to the temperate forests of the Sierra Madre Oriental (SMO) mountain range in Mexico. Lack of knowledge of its distribution has generated confusion over the assignment of the correct risk category. With the aim of predicting the distribution area of the Bearded Wood Partridge and contributing to strategies for its conservation, we updated and extended the knowledge of its distribution by modelling its ecological niche using GARP and MaxEnt algorithms. We also analysed its environmental distribution using principal components analysis, and contrasted the two most important environmental variables with the species’s distribution based on vegetation type. We found that the area potentially occupied by this species covers 17,956 km2 according to GARP and 12,974 km2 according to MaxEnt. We suggest that there is a biogeographic barrier which limits the distribution of this species in the southern part of its range. The abiotic variables that best explain its distribution are average annual precipitation and elevation, both of which coincide well with the distribution of cloud forest. A redefinition of the current range as recognised by IUCN is proposed along with the need to change its national risk category.
TL;DR: In this article, the authors conducted a transect survey covering dry and wet seasons in four major habitats on the Waza-Logone floodplain of Cameroon: dry grasslands, cultivated grassland, rice fields, and seasonally flooded grasslands resembling natural flood-plain vegetation.
Abstract: West African flood-plains have undergone major land-use transformations in the second half of the 20th century. To obtain insight in the effect of flood-plain development for irrigated rice cultivation on the abundance, richness, and diversity of Palearctic and Afrotropical raptors, we conducted monthly transect surveys covering dry and wet seasons in four major habitats on the Waza-Logone flood-plain of Cameroon: dry grasslands, cultivated grasslands, rice fields, and seasonally flooded grasslands resembling natural flood-plain vegetation. We recorded 36 raptor species among 2,533 individuals, dominated by Black Kite Milvus migrans, which comprised 42% of counts. Although richness and diversity were not related to land-use for Palearctic raptors, Afrotropical raptor diversity was higher on the flooded grasslands compared to the newly created cultivated habitats and dry grasslands. The abundance of Afrotropical raptors did not significantly differ across habitats but was lower in rice-fields when Black Kite and Hooded Vulture Necrosyrtes monachus were excluded. Conversely, Palearctic raptor abundance was highest in post-harvest rice fields, demonstrating the importance of the rice fields as foraging habitat for Palearctic raptors. Further transformation of West Africa’s flood-plains is expected, reducing their capacity for Afrotropical raptors, while Palearctic raptors may benefit from expansion of rice-fields, but more research is needed on their vulnerability to pesticide use.
TL;DR: It is shown that survival probability decreases linearly with bycatch, and that the by Catch is underestimated by at least 50%, confirming suspicions based on reviews of the bycatch survey procedures, and raising further concerns about the impact of longline fisheries on seabirds.
Abstract: Summary The incidental bycatch of seabirds in longline fisheries is one of the most striking examples of diffuse and incidental impact of human activities on vertebrate species. While there are various types of evidence of a strong impact of longline fisheries on seabirds, in particular albatrosses, the incidental bycatch mortality has never been directly linked to estimates of bycatch derived from on-board surveys. We develop a capture-recapture analysis which relates the annual probability of survival in the Black-Footed Albatross to the estimated absolute bycatch. By converting the absolute bycatch into an estimate relative to population size and using the theory of exploited populations, we show that survival probability decreases linearly with bycatch, and that the bycatch is underestimated by at least 50%, confirming suspicions based on reviews of the bycatch survey procedures, and raising further concerns about the impact of longline fisheries on seabirds.
TL;DR: In this article, seasonal changes in the availability of foraging habitats in farmland ecosystems should be considered when designing effective management strategies for the establishment of Japanese Crested Ibis populations.
Abstract: Seasonal foraging habitats, prey species and foraging frequency of Japanese Crested Ibis Nipponia nippon in farmland were studied one year after its reintroduction on Sado Island, Japan. Paddies were the main foraging habitat in spring, early summer, autumn and winter. In late summer, ibises often used levees around paddies, grasslands, uncropped paddies and abandoned paddies. Small invertebrates were important prey components in terms of frequency (70–90%) throughout the year. Ibises took Misgurnus loaches (less than 20% of prey captured) throughout the year; the capture rate of loaches in ditches was especially high in winter. Ibises depended on terrestrial invertebrates, including earthworms, particularly in late summer. No clear correlations between the rate of capture for each prey species and the proportion of habitat use in each season were detected. However, abandoned and uncropped paddies provided suitable habitats for the ibis because human disturbance was relatively low and the rate of capture for each prey type was relatively high throughout the year. Management of grass height in grasslands and on levees around the paddies will be effective in ensuring the availability of foraging habitats in late summer. Seasonal changes in the availability of foraging habitats in farmland ecosystems should be considered when designing effective management strategies for the establishment of Japanese Crested Ibis populations.
TL;DR: A survey of breeding frigatebirds in the Seychelles archipelago was conducted in 2011 and 2012 by counting adults on nests and chicks, and calculating the number of fledged birds.
Abstract: Summary We report the results of a survey of breeding Greater Frigatebird Fregata minor and Lesser Frigatebird F. ariel on Aldabra Atoll, a UNESCO World Heritage site in the Seychelles archipelago, which hosts the largest breeding population of frigatebirds in the Indian Ocean. All four colonies across the atoll were surveyed in 2011 and 2012 by counting adults on nests and chicks, and calculating the number of fledged birds. The breeding population in 2011 consisted of approximately 4,400 pairs of Greater Frigatebird and 6,600 pairs of Lesser Frigatebird. This is a potential increase of at least 10% since the last comparable surveys in 1976/77 and 2000 .H owever,2012 populations were considerably less than in 2011, highlighting significant annual variation and the need for more data. We also report a new breeding colony on the island of Picard, which was last reported to host breeding frigatebirds a century ago. We outline recommendations for future frigatebird monitoring on Aldabra and elsewhere and revisions to tourist regulations resulting from the census.
TL;DR: In this paper, the five largest of 11 remaining forest patches on Cebu were surveyed between March and June 2011, involving 64 post-sunset 500m walked transects with playback and habitat assessments.
Abstract: 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.
TL;DR: The first complete description of the nesting process in a Great Bustard population is provided, as well as important cues to the assessment of conservation measures implemented in Castro Verde, an area holding around 80% of the Portuguese population of this species.
Abstract: We present results on breeding parameters, nesting performance and nest habitat selection of the globally threatened Great Bustard Otis tarda, gathered during a 3-year study in Castro Verde (southern Portugal). A total of 107 nests were located. The estimated average onset of laying was 22 April (SD = 12 days, n = 8). The incubation period ranged from 25 March to 15 June. Nearly 95% of females incubated between 1 April and 31 May. Mean clutch size was 2.12 (SD = 0.69, n = 86), showing no significant inter-annual differences. There was no significant relationship between clutch size and average nest finding date, although, on average, nests were found later each year. Hatching occurred between 21 April and 26 June. The estimated proportion of eggs hatched per nest (hatching percentage) was 87.5% in 2002 (n = 8), 64.0% in 2003 (n = 33) and 75.8% in 2004 (n = 33). Overall nesting success for the three years was 71% (n = 107). The main causes of nesting failure were agricultural activities, mainly ploughing and harvesting, followed by corvid predation. Nests were spatially aggregated up to 800–1,500 m. At larger scales, the spatial distribution of nests can be considered random or uniform. Females showed a clear preference for nesting in cereal fields, followed by young fallows, old fallows, ploughed fields and then other habitats, although the intensity of selection of particular habitats varied between years. Nests were associated with both cereals and fallows, thus aggregating where those habitat types occurred within the study area. These results provide the first complete description of the nesting process in a Great Bustard population, as well as important cues to the assessment of conservation measures implemented in Castro Verde, an area holding around 80% of the Portuguese population of this species (application of EU agri-environmental schemes, power line signalling, water-point provision in dry years).