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Spatial distribution in a turkey vulture roost /Nauman, Lyle Edward, January 1965 (has links)
Thesis (M.S.)--Ohio State University, 1965. / Available online via OhioLINK's ETD Center
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Foraging ecology of Egyptian vultures in the Negev Desert, Israel.Meretsky, Vicky Jean. January 1995 (has links)
Egyptian vultures were observed at 3 kinds of feeding sites (randomly-placed sites stocked with 2 chicken carcasses, a fixed site stocked daily with 4 chicken carcasses, and a fixed site stocked 2x monthly with livestock carcasses) in the Negev desert, Israel, during breeding seasons of 1989 and 1990. Observations at large and small carcasses suggested Egyptian vultures were facultative social foragers; they invariably foraged in groups at predictable food supplies, but large flocks rarely gathered at small carcasses. Individuals did not recruit conspecifics to carcasses. Adults located more randomly-placed, small carcasses than other age-classes; at all sites they fed more intensively than nonadults and dominated them in aggressive encounters. These behaviors reflected the need to obtain more food in less time in order to feed and care for young. Egyptian vultures feeding at small-carcass sites had little competition from other species. Breeding adults made food deliveries to nests after feeding themselves. Adults fed out of proportion to their numbers because food items were small enough to defend effectively. Vigilance was strongly and consistently related to flock size. At the large-carcass site, griffon vultures and mammalian scavengers consumed the most food; Egyptian vultures experienced reduced and unpredictable access to food relative to small-carcass sites. Breeding adults made food deliveries to nests after gaining access to food, without feeding themselves first. Vigilance was unrelated to flock size, probably because other species determined access to food and risk of physical harm. Adults were unable to feed preferentially because food items were either too large (carcasses) or too small and diffuse (scraps, insects) to defend. Overall, most interactions of group and individual characteristics on individual feeding behavior were modified by site characteristics--chiefly perceived physical risk (due to unfamiliar surroundings or other competitors), food dispersion, and food availability. Supplemental feeding, an important tool for supporting threatened vulture populations, can benefit particular sizes or age-classes of vultures. Large vultures are favored by few, large carcasses with limited skinning. Small vultures are favored by small carcasses. Small vultures and subordinate vultures of all sizes are favored by many, easily accessed, well-dispersed food items.
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Power line risk to Cape (Gyps coprotheres) and white-backed (G. africanus) vultures in Southern AfricaHowes, Caroline G. January 2016 (has links)
A dissertation submitted to the Faculty of Science,
University of Witwatersrand,
in fulfilment of the requirements for the degree of Master of Science
Johannesburg, South Africa
March 2016 / This study examined the movements of white-backed (Gyps africanus) and Cape vultures (G. coprotheres) to assess their habitat preferences, measure seasonal changes in foraging behaviour, and examine where vultures are at risk of electrocution by and collision with power lines. White-backed and Cape vultures are two Old World vulture species found in southern Africa. They are listed as Critically Endangered and Endangered respectively, with massive population declines over the past three decades. These declines are due to poisoning, habitat loss, lack of food, use in traditional medicine, and electrical infrastructure mortality. Vultures provide key ecosystem services such as reducing disease transmission, cycling nutrients, and attracting tourists and therefore, a loss of vultures could cost the continent millions of US dollars.
Thirteen vultures (five white-backed and eight Cape vultures) were tracked using either DUCK-4A or BUBO-4A GPS-GSM trackers (Ecotone Telemetry, Sopot, Poland). Birds were tracked between April 2013 and October 2014. These data were used to examine the habitat suitability of both species using MaxEnt habitat suitability modelling. Key drivers of country-wide habitat suitability for white-backed vultures were mean temperature (30.9% contribution), precipitation seasonality (22.0% contribution), and biome (19.5% contribution), while key drivers for Cape vultures were distance to artificial feeding station (24.8% contribution), and precipitation seasonality (50.5% contribution). Anthropological variables (land use, cattle density, and population density) contributed very little to the models.
Using the same tracking data, seasonal changes in foraging movements were examined, particularly in relation to hypothetical food availability. Data were categorised by seasons (winter, spring, summer, and autumn) using weather data over the past decade. There was little evidence for seasonal movement in white-backed or Cape vultures which may be because food availability is not the limiting factor regardless of time of year.
Lastly, a model was constructed in MaxEnt using the Endangered Wildlife Trust’s Wildlife and Energy Programme dataset of white-backed and Cape vulture electrocutions by and collisions with power lines. Voltage was a major contributor to risk in every model for both collision and electrocution. This is likely to be related to the type and height of the power line structures rather than actual voltage. Either land use or population density also contributed to all four models. Slope contributed to white-backed vulture models while
feeding station and elevation contributed to Cape vulture models. Each of these variables probably relates not only to the likelihood of vulture presence but also how vultures behave in the area (e.g. flying lower in natural or low population areas to forage more effectively therefore putting them at higher risk of collision).
This study suggests that management initiatives should include carefully placing vulture feeding stations to change foraging patterns and provide safe, uncontaminated carrion, and proactive retrofitting of high risk power lines to reduce the high unnatural mortality in white-backed and Cape vultures in South Africa. It is important to continue to improve these models using more tracking data from more populations of white-backed and Cape vultures, and more electrocution and collision data gathered from regular, randomly selected power line surveys. / M T 2016
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A study of the bearded vulture Gypaetus barbatus in southern Africa.Brown, Christopher Justin. January 1988 (has links)
The Bearded Vulture Gypaetus barbatus has experienced a
substantial decrease in range in southern Africa during this
century. The present population, numbering about 200 pairs,
is confined mainly to the highlands of Lesotho and the Natal
Drakensberg. In these areas the birds breed successfully
(about 0,9 young/pair/year) and non-adult birds
about 36% of the total population.
constitute
The food supply was found not to be responsible for the
decline of Bearded Vultures on commercial farming areas in
South Africa. The use of poisons by farmers for the control
of mammalian predators is considered to be the most important
factor leading to the extinction of Bearded Vultures and
other scavenging species on farmlands.
Adult Bearded Vultures forage over an area of about
but were recorded up to 75 km from the nest. They
feed exclusively on carrion, at least 75% of which is derived
from domestic animals. Present conservation areas are not
large enough to contain the entire ranges of any pairs of
these birds or to supply sufficient food to support a viable
population throughout the year. The birds therefore have to
forage over commercial farmlands in South Africa and communal
areas in Lesotho.
This study, designed to be as broad-based as possible,
covers in detail the following aspects of Bearded Vulture
biology; age related characteristics, home range and
movements, feeding ecology, breeding biology, behaviour away
from the nest, energetics, distribution, status and
population dynamics and their conservation. In conclusion,
recommendations on the management and monitoring of the
population are offered. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1988.
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Diclofenac in Gyps vultures a molecular mechanism of toxicity /Naidoo, Vinasan. January 2007 (has links)
Thesis (PhD. (Paraclinical Studies))--University of Pretoria, 2004. / Includes bibliographical references.
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Techniques for releasing captive-reared vultures to the wildWallace, Michael Phillip. January 1983 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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Black and turkey vulture roost dynamics, marking, morphology and nesting in VirginiaSweeney, Thomas Medrick January 1984 (has links)
Black vulture (Coragyps atratus) and turkey vulture (Cathartes aura) roosting dynamics were studied at eight roosts near Radford, Virginia. Black vulture numbers at a permanent roost ranged from low monthly means in June 1982 and 1983 to peak monthly means in December 1981 and 1982. Turkey vulture numbers ranged from low monthly means in July 1982 and 1983 to peaks in December 1981 and 1983. Vultures used two temporary roosts at nearby landfills from March through October in 1983. Vultures marked with cattle eartags were observed moving among roosts. Road counts were poorly correlated (r = 0.39, P = 0.05, r = 0.39, P = 0.12, black vultures and turkey vultures respectively) with roosting vulture numbers, and may not be good indicators of vulture numbers. Long term monitoring of vulture populations is best accomplished by six counts in December, on the same date each year, as vultures leave permanent roosts. Movement of problem roosts may be most effective when accompanied by removal of attractants. Accretion of fecal material on metal leg bands constricted tarsi of black and turkey vultures. Teflon bands did not constrict the tarsus, but tag loss was high. Adult black vultures had longer tarsi and shorter wing chords than juveniles. Two nests were used in 1983 and 1984 by two pairs of black vultures, consisting of one marked and one unmarked bird. / Master of Science
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Home range, habitat use, behavior, and morphology of the Gettysburg vulturesColeman, John Samuel January 1985 (has links)
I investigated several aspects of black vulture (<u>Coragyps atratus</u>) and turkey vulture (<u>Cathartes aura</u>) ecology in southcentral Pennsylvania and northern Maryland. Black and turkey vultures did not move randomly over the study area but remained within large (X̅ = 15,993 and 62,953 ha respectively) home ranges. Ninety five percent of radioed vulture activity was within 15 km of the location at which the birds were trapped. Although home range size was not different between species, turkey vultures had greater variation in home range size. Within home ranges, while perched or roosting, vultures preferred forests and undeveloped areas and avoided cropland and urban areas. Nesting vultures only used caves within forested diabase rock formations. While feeding, birds preferred pasture and cropland and avoided forest and urban areas. Farm carrion was an important food resource for both species. Black vultures fed more on carrion greater than 15 kg in size than did turkey vultures. In winter vultures fed sooner after sunrise than in summer. Black and turkey vultures began laying eggs in mid-March and mid-April respectively. Nestling growth rates were higher for turkey vultures than for black vultures. Productivity as calculated by the Mayfield method was 0.73 and 0.42 young per active nest for black and turkey vultures respectively. Planned vegetation and road changes on Gettysburg National Military Park could affect the populations. Residential development outside the Park has had and will continue to have detrimental impacts on nesting habitat. / Master of Science
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Biochemical genetics, physiology and ecotoxicology of Southern African vulture speciesVan Wyk, Erika 11 September 2012 (has links)
D.Phil. / The main objective of this study was to describe the population genetic structure of African Whitebacked Vultures (Pseudogyps africanus) and to compare values to those previously documented for the Cape Griffon Vulture (Gyps coprotheres). The percentage of polymorphic .loci (P = 34.15%, 0.99 criterion) and average heterozygosity (17 = 0.108, ±0.032) calculated for P. africanus, confirm low levels of genetic -variation as reported for G. coprotheres. Blood samples' obtained from Lappetfaced (Torgos, tracheliotos) and Egyptian (Neophron percnopterus) Vultures enabled an evaluation of the genetic differentiation among the four southern African vulture species from allele frequency data assessed at 19 presumptive gene loci. Six (31.58%) of the 19 shared loci were polymorphic. Values of 1.26 (10.1), 26.32% and 0.076 (±0.047) for P.'africanus, 1.21 (±0.1), 21.05% and 0.097 (±0.045) for T. tracheliotos, 1.11 (±0.7), 21.05%. and 0.053 .(±0.053) for N: percnopterus and 1.05 (±0.5), 5.26% and 0.044 (±0.047) for G. coprotheres were obtained for the mean number of alleles per locus, P and Ti respectively. An average between-population fixigion index (FsT) value of 0.322 was obtained, which is indicative of significant (P < 0.01) differentiation between the four accipitrid species studied. Reference values for some haematological and plasma chemical parameters were established in 33 apparently normal, free-living, African Whitebacked Vulture nestlings. This .information can be. used in future ornithological research. A total of 27 variables . were examined, which include: leucocyte and erythrocyte counts, haemoglobin concentration, .haematocrit, haematimetric indices, glucose, creatinine, urea, total prOtein, albumin, globulin, albumin/globulin ratio, cholesterol, total lipids, triglycerides, aspartate aminotransferase, cholinesterase, lactate dehydrogenase, alkaline phosphatase, calcium, phosphorus, chloride, potassium, sodium and osmolarity. Only five parameters exhibited statistically significant (p < 0.05) differences between the two populations assayed. The Sandveld population showed elevated mean corpuscular haemoglobin concentration and alkaline phosphatase levels relative to the Dronfield population, whereas, the latter group displayed higher erythrocyte counts and potassium and sodium values than birds from the Sandveld community. Gaschromatography was used to establish the presence of quantifiable . residues .of 14 persistent chlorinated hydrocarbon pollutants in whole blood, clotted blood, heart, kidney, liver, bone, fat and muscle samples obtained from individual African Whitebacked, Cape. Griffon and Lappetfaced Vultures from different localities in South Africa. Concentrations of seven essential elements (Ca, Co, Cr, Cu, Fe, Mn and Zn) and four toxic metals (Al, Ni, Pb and Sr) were, furthermore, measured. The levels of pollutants measured in whole blood samples of live specimens were compared between nestlings from two natural breeding colonies, adults from a wildlife area and birds held in captivity. Statistically significant differences between populations were detected in geometric means calculated for y-BHC, a-chlordane and a-endosulfan. Five of the organochlorine contaminants displayed significant variations between concentrations detected in the clotted blood, organs and muscles excised from vulture carcasses. This includes residues ofy-BHC, a-chlordane, dieldrin, ,8-endosulfan and heptachlor epoxide. Values of the respective organochlorines obtained in vulture samples were generally low in comparison to results documented for a number of avian species. Levels of the , majority of metals analysed differed significantly- between two or more of the sampling localities, between adults and nestlings, and between captive and wild individuals. Metals which did not occur in such distinctly defining concentrations were Sr, Cu and Fe. Birds from Moholoholo maintained the highest overall blood metal burden, while nestlings from Dronfield were the least contaminated Significant differences were present between two or more tissues types for all the metals. The predominant sites for metal accumulation in vultures were the fatty tissues and bones. Most of the levels of metals measured in vultures compared well with concentrations reported for other avian species, and were generally within the range documented for species devoid of deleterious symptoms induced from heavy metal poisoning. However; certain individuals exhibited potentially toxic concentrations of specific metals such as Cu, Fe, Ni, and Pb. Continual monitoring of breeding colonies is recommended. The suitability of African Whitebacked Vulture nestlings as basic bioindicatori is highly advocated. The genetic data from this study can be used to compare levels of genetic diversity remaining in captive and wild vulture populations. An assessment of the amount and pattern of genetic variation of current populations of vulture species is an essential step towards ensuring the longterm survival of these birds. The phylogenetic conclusions found in. this study through allozyme electrophoresis correspond to results obtained from nucleotide sequence studies of the mitochondrial cytochrome b. gene. This points to an extent of positive corroboration between the two techniques. The haematological profile established for African Whitebacked Vulture nestlings constitutes a set of reference values that was previously unavailable for southern African vulture species. This data can assist in diagnosing and monitoring pathological and clinical' incidents detected in vultures. Values for a number of organochlo?ine pesticides and heavy metals, which have not been analysed in vulture species in the past, are documented. These values can serve as guidelines for future research, as well as control values for monitoring the occurrence and distribution of these contaminants within the habitats of vulture species. This study, therefore, presents information for research fields directly related to the survival of vulture populations. These factors must be included in future vulture management and reintroduction programmes as they will serve to enhance the success of conservation attempts.
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Ecological Dynamics of Vultures, Blackbuck Antelope, Khejeri Trees, and the Bishnoi People in Western Rajasthan, IndiaHall, Jonathan Clarence 27 September 2011 (has links)
No description available.
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