Vultur Research Articles

Condors, Water, and Mining: Heeding Voices from Andean Communities

This paper addresses the relationship between scholarship and activism, considering the obligations that ethnobiologists have to the communities we work with. I begin by describing the cultural meaning of Andean condors (Vultur gryphus) in Peru through their connections to mountains and water in various forms, and the condor’s role as guardian and protector. My research on condors led me to Indigenous beliefs and practices regarding sacred mountains and water, and from this to the threats against the environment posed by international mining operations. This discussion highlights questions concerning the scholar’s role in situations of environmental destruction and political conflict in relation to structural violence, the mass media, and climate change. At a time when those who protect the land and water are endangered around the globe, the decisions we make while conducting research carry responsibilities for the consequences of our actions, even as these consequences ripple out beyond our specific locality and our original intentions.

Evidence of genetic structure in a wide‐ranging and highly mobile soaring scavenger, the Andean condor

AbstractAimEvaluating the patterns of genetic variation and population connectivity is fundamental to effectively designing and implementing conservation strategies for threatened species. However, connectivity patterns in highly mobile vertebrates, and especially in avian species, are often overlooked as it is generally assumed to be driven by demographic panmixia or isolation by distance. Herein, we investigated the genetic structure and patterns of connectivity across four biomes in a highly vagile bird, the Andean condor (Vultur gryphus).LocationFour major Neotropical biomes of Argentina (>300,000 km2): Puna, Monte, Chaco and Patagonia.MethodsWe genotyped 13 polymorphic microsatellite loci plus one sex‐determining gene in 300 moulted feathers from 13 roosting sites in the core of species distributional range. We quantified levels of genetic differentiation, population structure, effective gene flow, genetic diversity and assessed sex‐biased dispersal events.ResultsWe detected genetic structure with a moderate differentiation between the north (Puna and Chaco) and south (Patagonia) regions with a contact zone in the central area (Monte). We observed a spatial pattern of genetic patches with higher levels of gene flow along the Andes range. Although we found no indication of bottlenecks or inbreeding, we observed larger effective population sizes in the south compared to the northern region.Main conclusionsOur study revealed that, despite the high dispersal potential of condors, demographic panmixia is not consolidated, even in the core of this species range. Our analyses further suggest that gene flow rate is modulated by topographic features, as condors may disperse more following the natural updrafts and lifts along the Andean mountains. Conservation initiatives should prioritize the protection of the Andean corridor to maintain connectivity between the apparent source from Patagonia to the northern biomes.

Preliminary Habitat Models of Foraging and Roosting Sites Used By Two Rehabilitated Adult Male Andean Condors (Vultur gryphus) In Peru

Satellite telemetry is widely used to generate information on species' use of space, which contributes to meeting conservation goals. Between June 2015 and September 2016, we obtained approximately 11,000 GPS points from two adult male Andean Condors (Vultur gryphus) that had been fitted with satellite transmitters and released in the central Andes of Peru. We used GPS coordinates and associated data to produce habitat distribution models (binomial Generalized Linear Models) from presence and pseudo-absence data of roosting sites and foraging areas visited by these individuals. The best potential habitats for Andean Condors in Peru were west of the Andes, from the border with Ecuador, south to Bolivia and Chile. Foraging areas of both individuals were at higher elevations than roosting sites (means: 3934 masl and 3356 masl, respectively). Roosting sites were in areas dominated by grasslands and agriculture, whereas foraging areas were dominated by puna grassland and brush. Conservation strategies for Andean Condors in Peru should be informed by data derived from satellite telemetry and should focus on preserving natural short vegetation above 3000 m west of the Andes for foraging and, for roosting sites, on maintaining areas free from the disturbances of road construction.

Tracking data and retrospective analyses of diet reveal the consequences of loss of marine subsidies for an obligate scavenger, the Andean condor.

Over the last century, marine mammals have been dramatically reduced in the world's oceans. We examined evidence that this change caused dietary and foraging pattern shifts of the Andean condor (Vultur gryphus) in Patagonia. We hypothesized that, after the decrease in marine mammals and the increase in human use of coastlines, condor diet changed to a more terrestrial diet, which in turn influenced their foraging patterns. We evaluated the diet by means of stable isotope analysis (δ13C, δ15N and δ34S) of current (last decade) and historical (1841-1933) feathers. We further evaluated the movement patterns of 23 condors using satellite tracking of individuals. Condors reduced their use of marine-derived prey in recent compared with historical times from 33 ± 13% to less than 8 ± 3% respectively; however, they still breed close to the coast. The average distance between the coast and nests was 62.5 km, but some nests were located close to the sea (less than 5 km). Therefore, some birds must travel up to 86 km from nesting sites, crossing over the mountain range to find food. The worldwide reduction in marine mammal carcasses, especially whales, may have major consequences on the foraging ecology of scavengers, as well as on the flux of marine inputs within terrestrial ecosystems.

Mercury in the feathers of bird scavengers from two areas of Patagonia (Argentina) under the influence of different anthropogenic activities: a preliminary study.

Mercury (Hg) is a global pollutant that bioaccumulates and biomagnifies in food chains and is associated with adverse effects in both humans and wildlife. We used feather samples from bird scavengers to evaluate Hg concentrations in two different areas of Northern Patagonia. Hg concentrations were analyzed in feathers obtained from turkey vultures (Cathartes aura), Black Vultures (Coragyps atratus), and southern crested caracaras (Caracara plancus) from the two areas of Northern Patagonia (Argentina): Bariloche and El Valle. Hg was detected in all the samples analyzed, but the concentrations can be considered low for the three species in both sampling areas. The mean concentration of Hg in Bariloche was 0.22 ± 0.16mg/kg dry weight (d.w.) in black vulture, 0.13 ± 0.06mg/kg d.w. in turkey vulture, and 0.13 ± 0.09mg/kg d.w. in southern crested caracara; in El Valle, the mean concentration of Hg was 1.02 ± 0.89mg/kg d.w. in black vulture, 0.53 ± 0.82mg/kg d.w. in turkey vulture, and 0.54 ± 0.74mg/kg d.w. in southern crested caracara. Hg concentrations in feathers were explained by the sampling area but not by the species. The concentrations of Hg contamination were comparable to those obtained in other studies of terrestrial raptors and aquatic bioindicator raptors. The species of the present study occur throughout much of North and South America. Thus, they may be appropriate bioindicators across the species' range, which is particularly useful as a surrogate, especially in distribution areas shared with endangered scavengers such as the California condor (Gymnopsys californianus) and the Andean Condor (Vultur gryphus).

Andean Condor Algorithm for cell formation problems

This paper proposes a novel population based optimization algorithm called Andean Condor Algorithm (ACA) for solving cell formation problems. The ACA metaheuristic is inspired by the movement pattern of the Andean Condor when it searches for food. This pattern of movement corresponds to the flight distance traveled by the Andean Condor from its nest to the place where food is found. This distance varies depending on the seasons of the year. The ACA metaheuristic presents a balance of its population through a performance indicator based on the average quality of the population’s fitness. This balance determines the number of Andean Condors that will perform an exploration or intensification movements. ACA metaheuristics have a flexible design. It allows to easily integrate specific heuristics according to the optimization problem to be solved. Two types of computational experiments have been performed. According to the results obtained it has been possible to determine that ACA is an algorithm with an outstanding RPD% in relation to the algorithms BAT, MBO and PSO, robust and with a convergence which tends not to be trapped in the local optimums. Besides, according to the non-parametric multiple comparison, results have been obtained in which the ACA metaheuristic has significant differences in relation to the BAT, MBO and PSO algorithms.

Hematological and Biochemical Parameters of Captive Andean Condors

Hematological and biochemical parameters are used to assess the health of birds and to support conservation plans for threatened species, such as the Andean Condor (Vultur gryphus). We studied 22 captive Andean Condors from the Rehabilitation Center for Raptors of the Union de Ornitologos of Chile to determine reference values. We measured packed cell volume, total plasma solids, and total and differential leukocyte counts; we analyzed aspartate aminotransferase, gamma-glutamyl transpeptidase, lactate dehydrogenase, alkaline phosphatase, creatine kinase, creatinine, calcium, inorganic phosphorus, and uric acid. We found no blood parasites and no significant differences between sexes (P > 0.05). Our results establish a baseline for hematological and serum biochemistry parameters for the Andean Condor.

Low‐frequency, threatened habitats drive the large‐scale distribution of Andean Condors in southern Patagonia

The analysis of factors that determine the distribution of top‐scavengers at large scales can provide clues to understanding important ecological processes and may be useful in establishing conservation and management strategies. Here, we conducted a large‐scale survey to study the distribution of the threatened Andean Condor Vultur gryphus in relation to environmental factors in southern Patagonia. This area has undergone the settlement of livestock and the introduction of exotic wildlife, although to a lesser extent than in the distribution of Condors in northern Patagonia. The aim of this study was to determine the relevance of different factors such as the availability of food resources, the availability of suitable nesting and roosting places and the presence of humans on large‐scale condor distribution. Our results show that the presence of meadows was the primary factor shaping Andean Condor distribution, despite the fact that this habitat occupies only 4% of the Patagonian landscapes. However, this habitat has a high probability of herbivore presence, so Condors seem to optimize their searching. The availability of nesting and roosting cliffs also contributed to explaining the observed distributions. Our results suggest that Condor distribution in southern Patagonia is a compromise between the spatial locations of two low‐frequency habitats – meadows and cliffs. A successful Condor conservation strategy in southern Patagonia should include the protection of these habitats and the regulation of farming expansion, including the recovery of meadows.

Trophic niche overlap among scavengers in Patagonia supports the condor-vulture competition hypothesis

SummaryAnimals that share resources tend to use different foraging strategies in order to decrease potential competition. Scavenging birds using the same nutritional resources can segregate into different space and time scales. However, it has been suggested that when the species do not co-evolve to achieve such segregation competition may result. Our aim was to study the trophic niche overlap between three species of obligate scavengers, the Andean CondorVultur gryphus, Turkey VultureCathartes auraand American Black VultureCoragyps atratus, which are the main avian consumers of carcasses in north-western Patagonia. Black Vultures arrived in the area relatively recently, have expanded their distribution following human activities, and have been suggested to compete with the threatened condor. We collected pellets in communal roosts of the three species to determine their diet, and to estimate the diversity (Shannon Index) and diet similarity (Pianka overlap index). We found that the Turkey Vulture has greater niche breadth and, apart from domestic livestock, it incorporates smaller items such as fish, reptiles and a great number of birds, carnivores and mice. Although the Black Vulture diet includes arthropods, they feed primarily on introduced ungulates, overlapping more with condor diet when roosting far from urban centres. As these latter two species share the same food resource, human activities that positively affect the abundance of the Black Vulture could increase competition among them, with possible implications for the conservation of the Andean Condor.

Education can improve the negative perception of a threatened long-lived scavenging bird, the Andean condor.

Human-wildlife conflicts currently represent one of the main conservation problems for wildlife species around the world. Vultures have serious conservation concerns, many of which are related to people's adverse perception about them due to the belief that they prey on livestock. Our aim was to assess local perception and the factors influencing people's perception of the largest scavenging bird in South America, the Andean condor. For this, we interviewed 112 people from Valle Fértil, San Juan province, a rural area of central west Argentina. Overall, people in the area mostly have an elementary education, and their most important activity is livestock rearing. The results showed that, in general, most people perceive the Andean condor as an injurious species and, in fact, some people recognize that they still kill condors. We identified two major factors that affect this perception, the education level of villagers and their relationship with livestock ranching. Our study suggests that conservation of condors and other similar scavengers depends on education programs designed to change the negative perception people have about them. Such programs should be particularly focused on ranchers since they are the ones who have the worst perception of these scavengers. We suggest that highlighting the central ecological role of scavengers and recovering their cultural value would be fundamental to reverse their persecution and their negative perception by people.

Sexual-size dimorphism modulates the trade-off between exploiting food and wind resources in a large avian scavenger

Animals are expected to synchronize activity routines with the temporal patterns at which resources appear in nature. Accordingly, species that depend on resources showing temporally mismatched patterns should be expected to schedule routines that balance the chances of exploiting each of them. Large avian scavengers depend on carcasses which are more likely available early in the morning, but they also depend on wind resources (i.e. uplifts) to subside flight which are stronger in afternoon hours. To understand how these birds deal with this potential trade-off, we studied the daily routines of GPS-tagged individuals of the world’s largest terrestrial soaring scavenger, the Andean condor (Vultur gryphus). Andean condors vary largely in weight and show a huge sexual dimorphism that allowed us to evaluate the effect of sex and body size on their daily routines. We found that condors use an intermediate solution strategy between the best times to exploit carcasses and uplifts, with this strategy changing over the year. Bigger males scheduled earlier routines that aligned more closely with uplift availability compared to smaller females, resulting in a partial temporal segregation between sexes. Condors’ routines reflect a sexual-size dependent trade-off that may underpin ecological and sociobiological traits of the studied population.

Extreme lightweight structures: avian feathers and bones

Flight is not the exclusive domain of birds; mammals (bats), insects, and some fish have independently developed this ability by the process of convergent evolution. Birds, however, greatly outperform other flying animals in efficiency and duration; for example the common swift (Apus apus) has recently been reported to regularly fly for periods of 10 months during migration. Birds owe this extraordinary capability to feathers and bones, which are extreme lightweight biological materials. They achieve this crucial function through their efficient design spanning multiple length scales. Both feathers and bones have unusual combinations of structural features organized hierarchically from nano- to macroscale and enable a balance between lightweight and bending/torsional stiffness and strength. The complementary features between the avian bone and feather are reviewed here, for the first time, and provide insights into nature's approach at creating structures optimized for flight. We reveal a novel aspect of the feather vane, showing that its barbule spacing is consistently within the range 8–16 μm for birds of hugely different masses such as Anna's Hummingbird (Calypte anna) (4 g) and the Andean Condor (Vultur gryphus) (11,000 g). Features of the feather and bone are examined using the structure-property relationships that define Materials Science. We elucidate the role of aerodynamic loading on observed reinforced macrostructural features and efficiently tailored shapes adapted for specialized applications, as well as composite material utilization. These unique features will inspire synthetic structures with maximized performance/weight for potential use in future transportation systems.

The energy landscape predicts flight height and wind turbine collision hazard in three species of large soaring raptor

Summary Collisions of large soaring raptors with wind turbines and other infrastructures represent a growing conservation concern. We describe a way to leverage knowledge about raptor soaring behaviour to forecast the probability that raptors fly in the rotor‐swept zone. Soaring raptors are theoretically expected to select energy sources (uplift) optimally, making their flight height dependent on uplift conditions. This approach can be used to forecast collision hazard when planning or operating wind farms. Empirical investigations of the factors influencing flight height have, however, so far been hindered by observation error. We propose a two‐pronged approach. First, we fitted state‐space models to z‐axis GPS tracking data to filter heavy‐tailed observation error and estimate the relationship between vertical movement parameters and weather variables describing the energy landscape (thermal and orographic uplift potential). Second, we fitted a mechanistic model of flight height above ground based on aerodynamics and resource selection theories. The approach was replicated for five GPS‐tracked Andean condors Vultur gryphus, eight griffon vultures Gyps fulvus, and six golden eagles Aquila chrysaetos. In all individuals, movement parameters correlated with thermal uplift potential in the expected direction. In all species, collision hazard was lowest for high thermal uplift potential values. Species specificities in the presence of a peak in collision hazard for medium values of thermal uplift potential could be explained by differences in wing loading and aspect ratio. Synthesis and applications. Our fitted models convert weather data (thermal uplift potential) into a prediction of collision hazard (probability to fly in the rotor‐swept zone), making it possible to prioritize different wind development projects with respect to the relative hazard they would pose to raptors. However, our model should be combined with post‐construction monitoring to document, and eventually account for turbine avoidance behaviours in collision rate predictions.

Guardian of the Andean heights. Conservation status of the Andean condor (Vulture Gryphus)

Guardian of the Andean heights. Conservation status of the Andean condor (Vulture Gryphus)

Reintroduction strategy for the Andean Condor Conservation Program, Argentina

The Andean condor Vultur gryphus is the largest bird in the world with flight capacity. For thousands of years the Andean condor has been honoured as a sacred link between space and humans by indigenous communities. In the last 100 years, the range of this emblematic species contracted rapidly and the Andean condor was pronounced extinct at both ends of its endemic South American range, in Venezuela and on the Atlantic coast of Patagonia. The Andean condor appears in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora and is listed as in ‘Danger of Extinction’ by the United States Fish and Wildlife Service. In addition, according to the International Union for Conservation of Nature, this species is classified as Near Threatened. In 1991, the Andean Condor Conservation Program (PCCA: Programa Conservación Cóndor Andino) was founded in Argentina. The PCCA started by performing genetic analyses and documenting the condor population in zoological institutions in a Latin American regional studbook. The PCCA then developed artificial‐incubation programmes and techniques for hand rearing birds without human contact, and worked to rescue and rehabilitate wild condors. The PCCA has succeeded in rearing 57 chicks and rescuing 197 wild condors. This paper describes the strategy used by the PCCA to reintroduce 160 condors throughout South America.

Puma predation subsidizes an obligate scavenger in the high Andes

SummaryThe ungulate–carnivore–vulture complex is a key trophic module of many terrestrial ecosystems, but one that is globally under threat. Few have explored cross‐species dependencies in this module, and the degree to which vultures rely on trophic facilitation by apex carnivores is rarely known and almost never quantified.We investigated the importance of pumaPuma concolorpredation on its native camelid prey, vicuñasVicugna vicugnaand guanacosLama guanicoe, in food provisioning for Andean condorsVultur gryphusin the high Andes of north‐western Argentina. We evaluated the origin of wild food sources through carcass surveys. We quantified condor feeding habits via foraging observations and through the analysis of pellet contents and stable isotopes from moulted feathers.Of the 102 fresh camelid carcasses we monitored, nearly all (94%) resulted from puma predation, and the majority (85%) of camelid carcasses used by condors were killed by pumas. Camelids represented 88% of the prey items identified from 183 condor pellets, and isotopic analyses of moulted feathers from 86 individuals identified via multilocus genotyping revealed that camelids and Small livestock were the most important prey items, representing 45–58% and 28–38% of condor assimilated biomass, respectively.Synthesis and applications. Our results show that puma predation plays a key role in the foraging ecology of Andean condors, and highlight the importance of predatory processes that make carrion available to scavengers. We contend that targeting the conservation of ungulate–carnivore–vulture modules, rather than a species‐specific approach, will be a more effective strategy to ensure the long‐term persistence of Andean condors and other obligate scavengers.

Repeated conservation threats across the Americas: High levels of blood and bone lead in the Andean Condor widen the problem to a continental scale

Wildlife lead exposure is an increasing conservation threat that is being widely investigated. However, for some areas of the world (e.g., South America) and certain species, research on this subject is still scarce or only local information is available. We analyzed the extent and intensity of lead exposure for a widely distributed threatened species, the Andean Condor (Vultur gryphus). We conducted the study at two different scales: 1) sampling of birds received for rehabilitation or necropsy in Argentina, and 2) bibliographic review and extensive survey considering exposure event for the species' distribution in South America. Wild condors from Argentina (n = 76) presented high lead levels consistent with both recent and previous exposure (up to 104 μg/dL blood level, mean 15.47 ± 21.21 μg/dL and up to 148.20 ppm bone level, mean 23.08 ± 31.39 ppm). In contrast, captive bred individuals -not exposed to lead contamination- had much lower lead levels (mean blood level 5.63 ± 3.08 μg/dL, and mean bone level 2.76 ± 3.06 ppm). Condors were exposed to lead throughout their entire range in continental Argentina, which represents almost sixty percent (>4000 km) of their geographical distribution. We also present evidence of lead exposure events in Chile, Ecuador, and Peru. Lead poisoning is a widespread major conservation threat for the Andean Condor, and probably other sympatric carnivores from South America. The high number and wide range of Andean Condors with lead values complement the results for the California Condor and other scavengers in North America suggesting lead poisoning is a continental threat. Urgent actions are needed to reduce this poison in the wild.

Sex‐dependent spatial structure of telomere length in a wild long‐lived scavenger

AbstractSex‐related divergences in many phenotypic traits, such as morphology, physiology, and behavior, have widely been described in animals. These asymmetries may adapt the sexes to different subniches, but also may produce sex‐specific optima for life‐history traits, as well as different costs. In birds, long movements in search of food and intraspecific competition may entail important metabolic costs that can be predicted to be unequal if both sexes perform somehow differently. However, the extent to which sex‐specific individual movements, foraging strategies and social dominance relationships are correlated with physiological costs has rarely been evaluated. The effects of prolonged exposure to stressors can be mirrored in accelerated cellular damage and aging as well as in the by‐products resulting from the activation of the stress response machinery. Both indicators, measured as telomere length and the concentration of feather corticosterone (CORTf), respectively, would reflect physiological costs at different time frames. Here, on the basis of information provided by GPS‐tagged Andean condors, a sexually dimorphic scavenger with a highly despotic social system, we determined whether sex‐specific movement patterns correlated to variation in telomere length and CORTf levels. We found a striking pattern of spatial structure of telomere length that was, in addition, sex‐specific; males breeding farther from feeding grounds exhibited longer telomeres, while the opposite pattern was found in females. Nevertheless, telomere length was not related to the range of movements performed by condors. We also found that females displayed higher CORTf values than males, regardless of the location of their nests, which is likely related to social dominance hierarchy and sexual size dimorphism. Sex‐specific optima for trade‐offs associated with ecological factors might underlie the fact that populations are spatially structured from a telomere‐length perspective, which has never been described before.

Multi-locus phylogenetic inference among New World Vultures (Aves: Cathartidae)

New World Vultures are large-bodied carrion feeding birds in the family Cathartidae, currently consisting of seven species from five genera with geographic distributions in North and South America. No study to date has included all cathartid species in a single phylogenetic analysis. In this study, we investigated the phylogenetic relationships among all cathartid species using five nuclear (nuc; 4060bp) and two mitochondrial (mt; 2165bp) DNA loci with fossil calibrated gene tree (27 outgroup taxa) and coalescent-based species tree (2 outgroup taxa) analyses. We also included an additional four nuclear loci (2578bp) for the species tree analysis to explore changes in nodal support values. Although the stem lineage is inferred to have originated ∼69 million years ago (Ma; 74.5–64.9 credible interval), a more recent basal split within Cathartidae was recovered at ∼14Ma (17.1–11.1 credible interval). Two primary clades were identified: (1) Black Vulture (Coragyps atratus) together with the three Cathartes species (Lesser C. burrovianus and Greater C. melambrotus Yellow-headed Vultures, and Turkey Vulture C. aura), and (2) King Vulture (Sarcoramphus papa), California (Gymnogyps californianus) and Andean (Vultur gryphus) Condors. Support for taxon relationships within the two basal clades were inconsistent between analyses with the exception of Black Vulture sister to a monophyletic Cathartes clade. Increased support for a yellow-headed vulture clade was recovered in the species tree analysis using the four additional nuclear loci. Overall, these results are in agreement with cathartid life history (e.g. olfaction ability and behavior) and contrasting habitat affinities among sister taxa with overlapping geographic distributions. More research is needed using additional molecular loci to further resolve the phylogenetic relationships within the two basal cathartid clades, as speciation appeared to have occurred in a relatively short period of time.

Cliff outcrops used as condor communal roosts are local hotspots of occupancy and intense use by other bird species

Cliff outcrops are structural components of the environment that can maintain a large variety of wildlife; however, they are still rather overlooked in conservation planning. We evaluate whether cliffs used by the Andean condor (Vultur gryphus) for communal roosting are associated with local aggregations of other bird species, and if their presence in combination with other local (vegetation cover, plant species richness, topographic heterogeneity) and regional (distance to water) environmental variables play a significant role in the structuring of local bird diversity. We selected twenty-four localities in north-western Patagonia (Argentina) to compare the abundance and richness of birds across four habitat types: a cliff used as condor roost (CC), closest cliffs to CC not used for roosting with the same (SC) or different (DC) aspect and the vegetation matrix surrounding the cliffs (MA). This led to 264 fixed 100m-radius points spread over 96 sampling sites. We recorded more individuals and species on cliffs than on MA; however, sample-based rarefaction curves showed that the high species richness observed on cliffs was actually the consequence of the high number of individuals recorded. Habitat type, vegetation cover and the richness of dominant vascular plants were the most important variables accounting the richness and abundance of birds. We concluded that condor roosts represent suitable habitats for the aggregation of individuals of other bird species thus leading to hotspots of occupancy and high species richness. Those cliffs should be reconsidered in the mapping of important conservation areas and for the proposal of mesofilter conservation strategies.