PubMed | The Peregrine Fund, Owyhee Desert Studies and Boise State University
Type: Journal Article | Journal: The Journal of animal ecology | Year: 2016
Warming temperatures cause temporal changes in growing seasons and prey abundance that drive earlier breeding by birds, especially dietary specialists within homogeneous habitat. Less is known about how generalists respond to climate-associated shifts in growing seasons or prey phenology, which may occur at different rates across land cover types. We studied whether breeding phenology of a generalist predator, the American kestrel (Falco sparverius), was associated with shifts in growing seasons and, presumably, prey abundance, in a mosaic of non-irrigated shrub/grasslands and irrigated crops/pastures. We examined the relationship between remotely-sensed normalized difference vegetation index (NDVI) and abundance of small mammals that, with insects, constitute approximately 93% of kestrel diet biomass. We used NDVI to estimate the start of the growing season (SoGS) in irrigated and non-irrigated lands from 1992 to 2015 and tested whether either estimate of annual SoGS predicted the timing of kestrel nesting. Finally, we examined relationships among irrigated SoGS, weather and crop planting. NDVI was a useful proxy for kestrel prey because it predicted small mammal abundance and past studies showed that NDVI predicts insect abundance. NDVI-estimated SoGS advanced significantly in irrigated lands (=-109030 SE) but not in non-irrigated lands (=-057053). Average date of kestrel nesting advanced 15days in the past 24years and was positively associated with the SoGS in irrigated lands, but not the SoGS in non-irrigated lands. Advanced SoGS in irrigated lands was related to earlier planting of crops after relatively warm winters, which were more common in recent years. Despite different patterns of SoGS change between land cover types, kestrel nesting phenology shifted with earlier prey availability in irrigated lands. Kestrels may preferentially track prey in irrigated lands over non-irrigated lands because of higher quality prey on irrigated lands, or earlier prey abundance may release former constraints on other selective pressures to breed early, such as seasonal declines in fecundity or competition for high-quality mates. This is one of the first examples of an association between human adaptation to climate change and shifts in breeding phenology of wildlife.
PubMed | Wildlife Conservation Society and The Peregrine Fund
Type: Journal Article | Journal: PloS one | Year: 2016
The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation.
Ogada D.L.,The Peregrine Fund |
Keesing F.,Bard College |
Virani M.Z.,The Peregrine Fund
Annals of the New York Academy of Sciences | Year: 2012
Vultures are nature's most successful scavengers, and they provide an array of ecological, economic, and cultural services. As the only known obligate scavengers, vultures are uniquely adapted to a scavenging lifestyle. Vultures' unique adaptations include soaring flight, keen eyesight, and extremely low pH levels in their stomachs. Presently, 14 of 23 (61%) vulture species worldwide are threatened with extinction, and the most rapid declines have occurred in the vulture-rich regions of Asia and Africa. The reasons for the population declines are varied, but poisoning or human persecution, or both, feature in the list of nearly every declining species. Deliberate poisoning of carnivores is likely the most widespread cause of vulture poisoning. In Asia, Gyps vultures have declined by >95% due to poisoning by the veterinary drug diclofenac, which was banned by regional governments in 2006. Human persecution of vultures has occurred for centuries, and shooting and deliberate poisoning are the most widely practiced activities. Ecological consequences of vulture declines include changes in community composition of scavengers at carcasses and an increased potential for disease transmission between mammalian scavengers at carcasses. There have been cultural and economic costs of vulture declines as well, particularly in Asia. In the wake of catastrophic vulture declines in Asia, regional governments, the international scientific and donor communities, and the media have given the crisis substantial attention. Even though the Asian vulture crisis focused attention on the plight of vultures worldwide, the situation for African vultures has received relatively little attention especially given the similar levels of population decline. While the Asian crisis has been largely linked to poisoning by diclofenac, vulture population declines in Africa have numerous causes, which have made conserving existing populations more difficult. And in Africa there has been little government support to conserve vultures despite mounting evidence of the major threats. In other regions with successful vulture conservation programs, a common theme is a huge investment of financial resources and highly skilled personnel, as well as political will and community support. © 2012 New York Academy of Sciences.
Mutia T.M.,Egerton University |
Mutia T.M.,Geothermal Development Company |
Virani M.Z.,The Peregrine Fund |
Moturi W.N.,Egerton University |
And 3 more authors.
Environmental Earth Sciences | Year: 2012
Following recent concerns of chemical pollution around Lake Naivasha, especially originating from recent agricultural activities in the catchment, samples of water, sediments, and fish Common carp (Cyprinus carpio) were collected from the Hippo Point, Kasarani, Mouth of Malewa River, Mouth of Karati River, Crescent Island, Sher Karuturi Discharge outlet and Oserian Bay for analysis of Cu, Cd and Pb by FAAS. The mean heavy metal levels ranged from 5.12-58.11 (Pb), 1.06-1.73 (Cd), and <0.03-2.29 (Cu) mg/kg wet weight in C. carpio muscle, <100-179.83 (Pb), <10.00-10.06 (Cd) and <30.00-32.33 (Cu) μg/L in surface water, and 17.11-53.07 (Pb), 1.18-5.58 (Cd) and 3.00-8.48 (Cu) mg/kg dry weight in sediment and showed a wide variation within and between samples with relatively high concentrations in sediments and fish muscle tissues. The results indicate that Lake Naivasha, in some parts, is polluted with these heavy metals of which relatively higher concentrations are found at the discharge outlets near Sher Karuturi and Oserian Bay. This indicates possible contribution from surrounding horticultural/floricultural activities and the Mouths of the Rivers Malewa and Karati which flow from it's upper catchment. © 2012 Springer-Verlag.
Virani M.Z.,The Peregrine Fund |
Kendall C.,Ornithology Section |
Kendall C.,Princeton University |
Njoroge P.,Ornithology Section |
Thomsett S.,Ornithology Section
Biological Conservation | Year: 2011
Vulture population declines have been noted in West and Southern Africa, but have not been assessed in East Africa. Roadside transects conducted in 1976 and 1988 were compared with surveys done from 2003-2005 in and around Masai Mara National Reserve, Kenya. Staggering declines in abundance were found for seven of eight scavenging raptors surveyed. No Egyptian vultures were seen during recent transects. We compared trends between the ungulate migration and non-migration season among three land use types (reserve, buffer, and grazed) and among the species surveyed to establish the causes of declines in scavenging raptors. Large declines during the ungulate migratory period suggest that most scavenging raptor species are declining well beyond the area of study. For all species, except Hooded vultures, substantial declines outside of the reserve indicate an important role of land use change in causing observed declines. In addition, significant declines of populations of Gyps species in the reserve itself, especially during the migration season, provide evidence that human activities occurring in other parts of the species' range such as poisoning of carcasses may be causing their decline. Declines found in this study suggest that at a minimum African white-backed, Rüppell's, and Hooded vultures should be relisted as Vulnerable. Management actions that limit land use change around the reserve combined with a countrywide ban on carbamate pesticides will be important for conserving keystone members of the scavenging guild. Future research should further examine possible causes of these declines and quantify the effect of reduced scavenging raptor abundance on scavenging efficiency. © 2010 Elsevier Ltd.
Ogada D.,The Peregrine Fund |
Botha A.,Endangered Wildlife Trust |
Shaw P.,University of St. Andrews
ORYX | Year: 2015
Four species of African vultures have been recategorized as Critically Endangered, and two as Endangered, on the IUCN Red List. Their declining status is attributed partly to the impacts of widespread poisoning. Prior to 2012 poisoning of vultures was mostly associated with illegal predator control by livestock farmers, in which vultures were typically unintended victims. More recently, ivory poachers have been using poisons to kill elephants Loxodonta africana or to contaminate their carcasses specifically to eliminate vultures, whose overhead circling might otherwise reveal the poachers’ presence. Between 2012 and 2014 we recorded 11 poaching-related incidents in seven African countries, in which 155 elephants and 2,044 vultures were killed. In at least two incidents the harvesting of vulture body parts (for fetish) may have provided an additional motive. We show that vulture mortality associated with ivory poaching has increased more rapidly than that associated with other poisoning incidents, and now accounts for one-third of all vulture poisonings recorded since 1970. This recent surge in the illegal use of poisons exposes weaknesses in the regulations, for which we propose measures aimed primarily at retail controls. However, because ivory poachers already operate outside any legal framework, African governments require international support in applying more punitive sentencing against mass wildlife poisoning. Copyright © Fauna & Flora International 2015
Anderson D.L.,The Peregrine Fund |
Koomjian W.,Ascending the Giants |
French B.,Ascending the Giants |
Altenhoff S.R.,Open City |
Luce J.,Ascending the Giants
Methods in Ecology and Evolution | Year: 2015
The availability of reliable information on tree climbing methods is critical for the development of canopy science and for the safety of workers accessing the forest canopy. To assess the breadth and quality of information contained in published climbing information, we performed searches in Web of Science and Google Scholar and evaluated 54 published sources on 10 predetermined criteria related to safety. We found a high incidence of unsafe recommendations that, if followed, could result in serious injury or death. Common errors included recommendations for equipment not suitable for tree climbing, advocating methods suitable for rock climbing but that can result in falls and trauma in tree climbing, and outdated information that no longer reflects best practices. We conclude by providing safety recommendations and a short review of tree climbing methods. This article thus serves as a guide for finding and interpreting best sources of methods for canopy access. © 2015 British Ecological Society.
Ogada D.L.,The Peregrine Fund
Annals of the New York Academy of Sciences | Year: 2014
Poisons have long been used to kill wildlife throughout the world. An evolution has occurred from the use of plant- and animal-based toxins to synthetic pesticides to kill wildlife, a method that is silent, cheap, easy, and effective. The use of pesticides to poison wildlife began in southern Africa, and predator populations were widely targeted and eliminated. A steep increase has recently been observed in the intensity of wildlife poisonings, with corresponding population declines. However, the majority of poisonings go unreported. Under national laws, it is illegal to hunt wildlife using poisons in 83% of African countries. Pesticide regulations are inadequate, and enforcement of existing legislation is poor. Few countries have forensic field protocols, and most lack storage and testing facilities. Methods used to poison wildlife include baiting carcasses, soaking grains in pesticide solution, mixing pesticides to form salt licks, and tainting waterholes. Carbofuran is the most widely abused pesticide in Africa. Common reasons for poisoning are control of damage-causing animals, harvesting fish and bushmeat, harvesting animals for traditional medicine, poaching for wildlife products, and killing wildlife sentinels (e.g., vultures because their aerial circling alerts authorities to poachers' activities). Populations of scavengers, particularly vultures, have been decimated by poisoning. Recommendations include banning pesticides, improving pesticide regulations and controlling distribution, better enforcement and stiffer penalties for offenders, increasing international support and awareness, and developing regional pesticide centers. © 2014 New York Academy of Sciences.
Ogada D.L.,The Peregrine Fund |
Buij R.,Leiden University
Ostrich | Year: 2011
The Hooded Vulture Necrosyrtes monachus is not currently listed on the IUCN Red List of threatened species, yet recent email discussions amongst a group of African raptor experts suggests this species may be in rapid decline. Information was solicited from raptor experts, as well as from published and unpublished reports, bird atlases, and individual sightings. No data was obtained for 8% of countries where the Hooded Vulture occurs and the value of the data obtained for the remaining countries varied widely in quality. Despite the variation in data quality, trends from each African region suggest dramatic population declines (mean 62%; range 45-77%) over the past 40-50 years. Some declines were documented in 20 years or less, indicating declines might be occurring rapidly in some areas. The major threats include poisoning, illegal trade for traditional medicine and bushmeat, and persecution. Based on quantitative rates of declines for each region, a revised population estimate for the species is a maximum of 197 000 individuals. We recommend that the Hooded Vulture is uplisted to Endangered under the IUCN Red List criteria. © 2011 Copyright Taylor and Francis Group, LLC.
PubMed | The Peregrine Fund and Boise State University
Type: | Journal: Ecological applications : a publication of the Ecological Society of America | Year: 2017
Despite common use, the efficacy of artificial breeding sites (e.g., nest boxes, bat houses, artificial burrows) as tools for monitoring and managing animals depends on the demography of target populations and availability of natural sites. Yet, the conditions enabling artificial breeding sites to be useful or informative have yet to be articulated. We use a stochastic simulation model to determine situations where artificial breeding sites are either useful or disadvantageous for monitoring and managing animals. Artificial breeding sites are a convenient tool for monitoring animals and therefore occupancy of artificial breeding sites is often used as an index of population levels. However, systematic changes in availability of sites that are not monitored might induce trends in occupancy of monitored sites-a situation rarely considered by monitoring programs. We therefore examine how systematic changes in unmonitored sites could bias inference from trends in the occupancy of monitored sites. Our model also allows us to examine effects on population levels if artificial breeding sites either increase or decrease population vital rates (survival and fecundity). We demonstrate that trends in occupancy of monitored sites are misleading if the number of unmonitored sites changes over time. Further, breeding site fidelity can cause an initial lag in occupancy of newly installed sites that could be misinterpreted as an increasing population, even when the population has been continuously declining. Importantly, provisioning of artificial breeding sites only benefits populations if breeding sites are limiting or if artificial sites increase vital rates. There are many situations where installation of artificial breeding sites, and their use in monitoring, can have unintended consequences. Managers should therefore not assume that provision of artificial breeding sites will necessarily benefit populations. Further, trends in occupancy of artificial breeding sites should be interpreted in light of potential changes in the availability of unmonitored sites and the potential of lags in occupancy owing to site fidelity. This article is protected by copyright. All rights reserved.