Modelling the effect of environmental variables on the reproductive success of Griffon Vulture (Gyps fulvus) in Sardinia,Italy

Old World vultures are experiencing dramatic population declines and now are among the species most threatened with extinction. Understanding the environmental variables that can influence the reproductive indexes of vulture populations can facilitate both habitat and species management. The aim of this study was to identify which environmental variables primarily affect the breeding successes of the Griffon Vulture Gyps fulvus in northern Sardinia by applying a Bayesian hierarchical model. A unique dataset of reproductive records (197 nests monitored over 39 years for a total of 992 breeding records) was used. Eight environmental and topographical variables describing the habitat at the nesting sites were considered as potential predictors of breeding success. These included mean annual temperature, mean annual precipitation, isothermality, elevation, the normalized difference vegetation index, wind speed, and the aspect and slope of the land surface. In addition, we also considered the effect of human disturbance and the type of nest. According to our best model, the probability of successfully raising a chick in Griffon Vultures was higher in nests exposed to a high wind speed, not covered by natural shelters, where the vegetation was mostly represented by shrub and pastures, with low human disturbance and in years with low rainfall. This model will be useful for management of the breeding habitat and to identify the area most suitable for Griffon Vulture reproduction. This information is crucial for programming conservation measures aimed at enlarging the area of occupancy of the species.     

SOME OBSERVATIONS ON BEHAVIOUR AND CALL IN THE PALM THRUSH CICHLADUSA ARQUATA

Boshoff, A. F. &; Vernon, C. J. 1980. The past and present distribution and status of the Cape Vulture in the Cape Province. Ostrich 51:230-250.

Because of the apparent decline in range and numbers of the Cape Vulture Gyps coprotheres in the Cape Province, the distribution and status of this species were reviewed according to four time periods from before 1905 to the present day. All available information was assembled, assessed and interpreted. It is apparent that, although the present decline is real, the population has undergone previous fluctuations. The magnitude, nature and possible causes of the fluctuations are discussed. It is postulated that the drastic decline in the game herds, particularly during the 19th century, together with the recent changes in stock farming, are the most important factors determining the numbers and distribution of Cape Vultures. Direct and indirect persecution also have a detrimental effect on vulture populations. Farmers' attitudes towards vultures are mentioned and conservation priorities and problems are listed.     

Assessing the accuracy of plotless density estimators using census counts to refine population estimates of the vultures of Kruger National Park

Breeding population estimates for three vulture species in Kruger National Park (KNP), South Africa, were made in 2013 using data from aerial censuses and a plotless density estimator (PDE). PDEs are distance-based methods used to assess sparse populations unsuitable for plot-based methods. A correction factor was applied to the 2013 estimates to reflect the difference between the survey counts and the PDE figures. We flew additional censuses across most of KNP and counted all visible nests to assess the 2013 estimates. Survey counts were within 95% confidence limits of corrected PDE estimates for White-backed Vulture Gyps africanus (count: 892; estimate: 904 [95% CI ±162]), at the limit of confidence for White-headed Vulture Trigonoceps occipitalis (count: 48; estimate: 60 [±13]) and outside confidence limits for Lappet-faced Vulture Torgos tracheliotos (count: 44; estimate: 78 [±18]). Uncorrected PDE estimates accurately reflected White-headed and Lappet-faced Vulture nest counts. The clustered patterns of White-backed Vulture nests and dispersed patterns of White-headed and Lappet-faced Vulture nests offer an explanation for these results and means that corrected PDE densities are inaccurate for estimating dispersed nests but accurate for estimating clustered nests. Using PDE methods, aerial surveys over ～35% of KNP are probably sufficient to assess changes in these vulture populations over time. Our results highlight these globally important breeding populations.     

Home-range size and movement patterns of Hooded Vultures Necrosyrtes monachus in southern Africa

Hooded Vulture Necrosyrtes monachus populations have declined dramatically in recent years, but we know little about their ecology. We radio-tagged four vultures in northern Botswana to gather data on animal movement and home-range patterns. Hooded Vultures were primarily sedentary at night. Hooded Vultures moved similar distances and speeds during the wet and dry season, and travelled over similar home ranges as measured using minimum convex polygons (MCP), but used much smaller core areas during the dry (breeding) season. We found significant differences in mean distances and speeds moved among different birds, and when comparing day to night, but not between the wet (non-breeding) and dry (breeding) season or by year. All of the variables we tested, including individual vulture differences, season, year and number of fixes, significantly influenced 95% MCP and kernel density estimate (KDE) home-range sizes. Hooded Vultures used significantly smaller KDE home-range sizes during the dry (breeding season) than in the wet (non-breeding) season. Hooded Vultures travelled smaller daily distances over smaller home ranges than most other vulture species for which data exist.     

Nesting habitat preference of the African White-backed Vulture Gyps africanus and the effects of anthropogenic disturbance

The African White-backed Vulture Gyps africanus is widely distributed across sub-Saharan Africa but populations are in decline. Loss of suitable habitat for foraging and breeding are among the most important causes, and future conservation will require identification of suitable remaining habitat and the threats to it and to the vultures in it. Like many large raptors, African White-backed Vultures have a long breeding cycle and thus spend much of each year near their nest site, but ecological correlates of nest sites have not been quantified for any African vulture species. We use nest-site data for African White-backed Vultures collected during aerial and ground surveys and habitat data derived from a GIS to develop statistical models that estimate the probability of nest presence in relation to habitat characteristics, and test these models against an independent dataset. The models predicted that both direct and indirect disturbance by humans limit the potential distribution. Suitable habitat needs to be identified and receive adequate protection from poaching. Poaching of vultures is thought to be mainly for use in traditional medicine and does not target any particular species, so all vulture species can be considered equally at risk. We predict the likelihood of individuals nesting in currently unprotected areas should they become protected. These predictions show that readily available GIS data combined with relatively simple statistical modelling can provide meaningful large-scale predictions of habitat availability.     

4. ONE YEAR'S CENSUS AND STUDY OF BIRDS IN 2½ ACRES OF ALEANY BUSHVELD. (Part 2.) April, 1945, to March, 1946

Hooded Vultures Necrosyrtes monachus are critically endangered but little is known of their year-round use of nests or whether other species usurp Hooded Vulture nest sites. We investigated visitation rates by Hooded Vultures and other species (including potential nest predators and usurpers) to examine their effect on Hooded Vulture breeding success. We present observations of 33 species recorded by camera traps at 12 Hooded Vulture nests over a total of 93 nest-months (2 095 nest-days). Several pairs of Hooded Vultures visited their nests regularly during the non-breeding season, some adding nesting material, highlighting that pairs visited their nest(s) year round. Egyptian Geese Alopochen aegyptiaca, potential usurpers of raptor nests, were present at occupied and unoccupied Hooded Vulture nests, but we recorded no usurpation of nests by Egyptian Geese and they had no impact on vulture breeding success. Hooded Vulture breeding failure was linked to two species only: camera-trap imagery recorded one case of predation of a vulture egg by a Chacma Baboon Papio ursinus, and one case of a Martial Eagle Polemaetus bellicosus predating a vulture nestling. We recommend expanding the Hooded Vulture nest monitoring programme to include more pairs.     

A Global Review of Causes of Morbidity and Mortality in Free-Living Vultures

Vulture species worldwide play a key role in ecosystems as obligate scavengers, and several populations have had precipitous declines. Research on vulture health is critical to conservation efforts including free-living vultures and captive breeding programs, but is limited to date. In this systematic review, we determined the reported causes of free-living vulture species morbidity and mortality worldwide. The most commonly reported cause of mortality was from toxins (60%), especially lead and pesticides, followed by traumatic injury (49%), including collisions with urban infrastructure and gunshot. Neglected areas of research in free-living vulture health include infectious diseases (16%), endocrine and nutritional disorders (6%), and neoplasia (<?1%). Almost half of the studies included in the review were conducted in either Spain or the USA, with a paucity of studies conducted in South America and sub-Saharan Africa. The highest number of studies was on Griffon (Gyps fulvus) (24%) and Egyptian vultures (Neophron percnopterus) (19%), while half of all vulture species had five or fewer studies. Future investigations on free-living vulture health should focus on neglected areas of research, such as infectious diseases, and areas with gaps in the current literature, such as South America, sub-Saharan Africa, and under-studied vulture species.

     

Significant population of Egyptian Vulture Neophron percnopterus found in Morocco

The Egyptian Vulture Neophron percnopterus population in Morocco has undergone a marked decline since the 1980s to the point of nearing local extinction in the twenty-first century. A field study of some possible sites for Egyptian Vultures was carried out over six days during June 2014 in the Middle Atlas Mountains, Morocco. We counted a total of 48 Egyptian Vultures at three different localities: two occupied breeding sites and one communal roost that hosted 40 vultures of different ages. A (probable) singe adult bird at the breeding site was located and a previously occupied site was also visited. A preliminary survey amongst local people indicated that threats faced by this species are predator poisoning in some areas, and the use of vulture parts for traditional medicine. Given that the species is considered globally Endangered and populations continue to decline in many areas, the discovered population reported here, although relatively small, is of national and regional (North-west Africa) importance. We expect this new situation will revive the hopes for studying and conserving this and other vulture species in Morocco and North-west Africa in general.     

Establishment of selected baseline blood chemistry and hematologic parameters in captive and wild-caught African white-backed vultures (Gyps africanus)

Despite the devastating collapse of three vulture populations on the Asian subcontinent as a result of their exposure to diclofenac, there is little available information on the normal physiology of many vulture species, including the African White-backed Vulture (Gyps africanus). Such information is needed to fully understand mechanisms for toxicity and to identify and prevent future health problems. The aim of this study was to establish baseline parameters for hematologic and selected serum chemistry parameters for this model species for further studies into the toxicity of diclofenac. Captive nonreleasable and wild African White-backed Vultures were used to determine reference values. For hematology, erythrocyte counts, hemoglobin concentration, hematocrit, packed cell volume, mean corpuscular volume, mean corpuscular hemoglobin concentration, and total and differential leukocyte counts were measured. Chemical analytes measured included sodium, potassium, calcium, albumin, and globulin concentrations, aspartate aminotransferase, creatine kinase, and alanine aminotransferase activities. Uric acid and urea concentrations and the urea:uric acid ratio also were evaluated. Values are presented as means, standard deviations, and reference intervals. The serum chemistry parameters selected may provide a starting point for the evaluation of changes in renal and hepatic function; these organ systems are most severely affected by diclofenac. Results were also compared with values reported for G. africanus nestlings, and from these results it is evident that the clinical pathologic parameters are age related. This indicates that the use of nestling values for the evaluation of clinical pathologic findings in adults may be unreliable and could lead to incorrect assumptions.     

Genetic diversity is retained in a bottlenecked Cinereous Vulture population in Turkey

Vulture populations worldwide have suffered precipitous declines in recent decades. The Cinereous Vulture Aegypius monachus, a highly philopatric scavenger distributed across southern Europe and the central Asian plateau, is threatened in many parts of its range. Turkey holds the second largest population of this species in the Western Palaearctic, but there has been no research on its genetic structure and the possible implications of this structure for the future of the species. Here we report nuclear diversity and relatedness determined by short tandem repeat genotyping of 81 individuals from the four largest colonies. Our results demonstrated no significant genetic structuring, suggesting a single panmictic metapopulation connected by frequent dispersal. Furthermore, we show that the study population has retained moderate levels of genetic diversity, despite passing through a recent demographic bottleneck. We estimated the effective population size to be 112 individuals (95% confidence interval 74–201). Our results imply that the observed lack of increase in population size since the 1990s has not been caused by lowered fitness due to genetic inbreeding but rather by increased mortality via demographic processes. In the short term, we suggest that conservation efforts should treat the Turkish subpopulations as a single management unit and aim to increase population size through effective protection, especially during the breeding season.     

Raptor conservation in the Northern Cape Province,South Africa

Anderson, M.D. 2000. Raptor conservation in the Northern Cape Province, South Africa. Ostrich 71 (1 & 2): 25–32.

The semi-arid Northern Cape is the largest and most sparsely populated province in South Africa. One of the main economic activities is sheep farming, and the properties are generally very large (>5 000 ha). A heterogeneous environment results in many habitats for a wide diversity of raptors. Fifty-one different species have been recorded, of which 37 are resident, 21 are common, and eight species are listed in the South African Red Data Book—Birds. As habitat degradation is limited, besides the areas immediately adjacent to the perennial rivers, raptors are still commonly encountered in many areas. Conflict with small-stock farming, however, results in some birds being inadvertently or directly persecuted each year. Two farmer questionnaire postal surveys (1976 and 1992) indicated a decrease in range and abundance of certain scavenging species, such as the Tawny Eagle. The more recent survey also indicated that most stock mortalities occurred in the mountainous areas, with the Black Eagle being the apparent culprit. In the Northern Cape there are both positive and negative anthropogenic effects on raptors. For example, 14 species have been recorded breeding on man-made structures, while 18 species have been documented to drown in farm reservoirs. Through the activities of the Raptor Conservation Group, the Northern Cape Nature Conservation Service and the Northern Cape Raptor Conservation Forum various threats are being addressed. Raptor conservation activities include: monitoring of raptor breeding populations, road censuses, farmer extension, establishment of raptor conservancies, rehabilitation of injured raptors, issuing of certificates to land-owners who have breeding raptors on their properties, presentation of the annual Gariep Raptor Conservationist Award, production and distribution of raptor pamphlets and booklets, modification of farm reservoirs to prevent raptor drownings, modification of powerlines to prevent electrocutions, and establishment of “vulture restaurants”. Through these efforts, the status of many raptor species is improving and species such as the Bateleur and Lappet-faced Vulture are becoming increasingly common.     

Recording raptor behavior on the wing via accelerometry

ABSTRACT.   Measuring body movements using accelerometry data loggers is a relatively new technique, the full applicability of which has yet to be tested on volant birds. Our study illustrates the potential of accelerometry for research on large birds by using the technique to record the behavior of three species of raptors, mainly during flight. A tri-axial accelerometer was deployed on a trained Harris' Hawk ( Parabuteo unicinctus ), Tawny Eagle ( Aquila rapax ), and Griffon Vulture ( Gyps fulvus ). Comparison of flight-related variables calculated from video footage and that estimated from the acceleration data showed that the latter provided considerable and accurate information (usually <10% error) about the behavior of the birds, including wing-beat frequency and when they glided and flapped. Acceleration data permitted tentative comparisons of relative movement-specific rates of energy expenditure for the Griffon Vulture flying up versus flying down a small hill. The accelerometry data appeared to suggest, as expected, that the Griffon Vulture expended more energy flying uphill than flying back down. Our preliminary findings indicate that studies using accelerometers can likely provide information about the detailed time–energy budgets of large birds. Such information would aid in comparative analyses of behavior and energetics, and may also enhance efforts to conserve declining bird populations.     

Morphological abnormalities in anurans from southern Brazil

In recent years, the progressive decline in populations of anuran amphibians has left many species increasingly vulnerable to extinction. The potential role of morphological abnormalities as a mechanism of this decline has attracted attention in many recent studies. We investigated the occurrence and frequency of morphological abnormalities in anurans from northern of the state of Rio Grande do Sul, Brazil. We sampled 1674 individuals from three different environments – forest, farmland and peri‐urban areas – between 2001 and 2017. We recorded 89 individuals with morphological abnormalities, with 12 different types of abnormality in 19 anuran species. We recorded nine types of abnormality in forest and seven in the farmland, with brachydactyly being the most common abnormality in both areas. Only three abnormalities were recorded in the peri‐urban area, and all three were equally frequent. Studies of morphological alterations provide important insights into the potential effects of environmental impacts on anuran populations and may be essential for the planning of effective conservation strategies.     

Nesting distribution of vultures in relation to land use in Swaziland

Three species of vulture (African White-backed, White-headed and Lappet-faced) breed in Swaziland, all of which are threatened within the country. Vulture nests were surveyed using a fix-winged aircraft in low-lying savannas of Swaziland. Nesting was observed in three land use categories: (1) unprotected government cattle ranches, (2) protected cattle ranches, and (3) conservation areas. A total of 248 nests was recorded, of which 240 belonged to the African White-backed Vulture. Nesting densities were highest in conservation areas, an order of magnitude lower on protected cattle ranches and negligible on government ranches. Nests of White-headed Vultures and Lappet-faced Vultures were exclusively located in conservation areas. Nesting densities of African White-backed Vultures in some conservation areas exceeded 260 nests/100 km², which are the highest known densities of this species anywhere in Africa. Nests were almost exclusively located in riparian vegetation, but at Hlane National Park a large proportion of nests were placed in open woodland, possibly as a result of an influx of vultures from adjoining agricultural lands that have only been transformed in recent decades. Where elephants were present in conservation areas, vultures did not nest within their enclosures. The location and density of vulture nests may possibly be used as an indicator of pressure on biological resources in low-lying savannas of Swaziland.     

The Vulture in the Sky and the Hominin on the Land: Three Million Years of Human–Vulture Interaction

ABSTRACT

Vultures and humans have been sympatric for millions of years and evidence from the archaeological and historical records suggests interdependence over long periods. Like other species, early hominins probably used these birds to locate carcasses in the landscape. With the evolution of large-bodied and more encephalized hominins, the quest for high-quality food would have intensified. Vultures used as beacons for meat may have been particularly important to hominins dispersing out of Africa, facilitating the occupation of new landscapes. Neanderthals and prehistoric modern humans incorporated vulture parts into their culture, and while the symbolic and ritualistic significance of the birds may have varied through time and across cultures, their link with positive life forces is apparent. More recently, the intensification of farming and modern sanitary restrictions, as well as the spread of human populations, has led to the radical decline in vulture populations throughout the world. Without commitments by governments to fund vulture conservation programs, the ability to preserve many species may be limited over the long term. In this review paper we discuss the ability of vultures to act as beacons signaling meat in the landscape and our changing relationships with these enigmatic birds through a shared history. Within this narrative, we outline why vultures are fundamental to maintaining our ecosystem and should therefore be protected.     

Out in the cold – how big and how old? Genetic fingerprinting reveals long‐lived individuals withstand climatic oscillations in the arctic‐alpine

In long‐lived, clonally reproducing species, assessing organism size is a nontrivial endeavour because each genetically distinct entity (genet) may comprise multiple modular units (ramets). Attributes of clonally reproducing populations, such as genet size, longevity and clonal diversity (the number of genets in a population), have significant implications for the persistence of populations over time. In the context of climate change, population persistence contributes to community stability and ecosystem resilience. Do clonal individuals persist through periods of climatic oscillations? Are clonal populations composed of a few large and persistent clones, or do they include clones of different sizes and ages? In this issue, de Witte et al. (2012) present an exciting analysis of clonal diversity and genet longevity in populations of four arctic‐alpine plant species with contrasting life histories: Carex curvula, Dryas octopetala, Salix herbacea and Vaccinium uliginosum. Using amplified fragment length polymorphism (AFLP) data, the authors demonstrate that genet size ranged from a few centimetres to 18 metres and age estimates for the largest genets ranged from 500 to 4900 years. These data reveal that clonally reproducing populations include individuals that have outlived significant changes in climate. Despite the longevity of some individuals, clonal diversity within populations was high, with most individuals existing as small, relatively young genets. Long‐lived individuals, together with high numbers of younger plants, ensure repeated recruitment and population persistence over time. This study represents a novel and timely contribution to a growing body of work aimed at understanding population persistence in changing climates.     

Stable isotope evidence for Turkey Vulture reliance on food subsidies from the sea

Turkey Vulture (Cathartes aura) reliance on marine subsidies in coastal Baja California peninsula was quantitatively assessed by analyzing carbon and nitrogen stable isotope ratios in its feathers. Feathers were collected in two separate roosts in a small farm, a small fishing village and an uninhabited beach. We compared among them the isotopic niches of the four populations and also with those of Yellow-footed Seagull (Larus livens), Brown Pelican (Pelecanus occidentalis) and Orange-throated Whiptail lizard (Aspidoscelis hyperythra), used as reference for sympatric marine and terrestrial species. The importance of nutrients of marine origin varied among local close subpopulations, suggesting some spatial segregation. Dominant individuals would be established near predictable sources of food (human settlements), having a mixed terrestrial–marine diet influenced by local human activities (isotopic signature of feathers also indicated the role of human-fed cattle as vulture food). Subordinate individuals would be relegated to wandering along the beaches searching for washed up food, having a diet almost exclusively marine.     

Uneven Large-Scale Movement Patterns in Wild and Reintroduced Pre-Adult Bearded Vultures: Conservation Implications

After the quasi-extinction of much of the European vertebrate megafauna during the last few centuries, many reintroduction projects seek to restore decimated populations. However, the future of numerous species depends on the management scenarios of metapopulations where the flow of individuals can be critical to ensure their viability. This is the case of the bearded vulture Gypaetus barbatus, an Old World, large body-sized and long-lived scavenger living in mountain ranges. Although persecution in Western Europe restrained it to the Pyrenees, the species is nowadays present in other mountains thanks to reintroduction projects. We examined the movement patterns of pre-adult non-breeding individuals born in the wild population of the Pyrenees (n = 9) and in the reintroduced populations of the Alps (n = 24) and Andalusia (n = 13). Most birds were equipped with GPS-GSM radio transmitters, which allowed accurate determination of individual dispersal patterns. Two estimators were considered: i) step length (i.e., the distance travelled per day by each individual, calculated considering only successive days); and ii) total dispersal distance (i.e., the distance travelled between each mean daily location and the point of release). Both dispersal estimators showed a positive relationship with age but were also highly dependent on the source population, birds in Andalusia and Alps moving farther than in Pyrenees. Future research should confirm if differences in dispersal distances are the rule, in which case the dynamics of future populations would be strongly influenced. In summary, our findings highlight that inter-population differences can affect the flow of individuals among patches (a key aspect to ensure the viability of the European metapopulation of the endangered bearded vulture), and thus should be taken into account when planning reintroduction programs. This result also raises questions about whether similar scenarios may occur in other restoration projects of European megafauna.     

Implications of bacterial,viral and mycotic microorganisms in vultures for wildlife conservation,ecosystem services and public health

The effects that microorganisms (bacteria, viruses and fungi) have on their hosts remain unexplored for most vulture species. This is especially relevant for vultures, as their diet consists of carcasses in various stages of decomposition, which are breeding grounds for potentially pathogenic microorganisms. Here we review current knowledge of bacterial, viral and mycotic microorganisms present in wild vultures. We consider their potential to cause disease in vultures and whether this poses any population-level threats. Furthermore, we address the question of whether vultures may act as disease spreaders or mitigators. We found 76 articles concerning bacterial, viral and mycotic microorganisms present in 13 vulture species, 57 evaluating bacteria, 13 evaluating viruses and six evaluating mycotic microorganisms. These studies come from all continents where vultures are present, but mainly from Europe and North America, and the most studied species was the Griffon Vulture Gyps fulvus. We found that vultures are colonized by zoonotic pathogens, and even host-specific human pathogens. Some recorded bacteria showed multi-antibiotic resistance, especially those that can be associated with anthropogenic food subsides such as supplementary feeding stations. We found evidence that vulture health can be affected by some microorganisms, producing a wide array of clinical alterations that have the potential to influence mortality risk and fitness. We did not find clear scientific evidence that vultures play an epidemiological role spreading microorganisms to humans and other species. However, there is evidence that vultures could prevent the spread of infectious diseases through their removal of decomposing organic material. The evaluation of vulture exposure to microorganisms is of fundamental importance to design better conservation policies for this threatened group, which may serve a key role as ecosystem cleaners.     

Isolation and characterization of 18 microsatellite loci in the Egyptian vulture (Neophron percnopterus)

We developed 18 new microsatellite loci for the endangered Egyptian vulture (Neophron percnopterus). Microsatellite loci were screened for variation in two different populations belonging to separate subspecies: the nominal N. p. percnopterus and the Canarian N. p. majorensis. Mean expected heterosygosities were respectively 0.51 and 0.46, while the mean number of alleles per locus was 4.7 and 3.9. These new markers allow further genetic studies for the endangered Canarian Egyptian Vulture.