Ornithology Section

Nairobi, Kenya

Ornithology Section

Nairobi, Kenya

Time filter

Source Type

Virani M.Z.,Peregrine Fund | Monadjem A.,University of Swaziland | Thomsett S.,Ornithology Section | Kendall C.,Ornithology Section | Kendall C.,Princeton University
Bird Conservation International | Year: 2012

Vulture populations have been declining globally and regionally within Africa. Rüppell's Vulture Gyps rueppellii is currently listed as Near Threatened' and numbers of the species, along with African White-backed Vultures G. africanus, have declined by 52% in and around the Mara-Serengeti ecosystem. A large breeding colony of Rüppell's Vulture at Kwenia, southern Kenya, was monitored between 2002 and 2009. Around 150-200 adults were present on each visit, with up to 64 simultaneously active nests. The date of egg-laying differed considerably between years, with two discrete breeding attempts in some years. Nests were not positioned randomly across the cliff face and the number of active nests was related to rainfall in the previous year. The large ungulate migration of the Mara-Serengeti provides a vital foraging ground for the species. Conservation implications of the loss of vultures are discussed. © Copyright Â(c) BirdLife International 2012.

Virani M.,The Peregrine Fund | Kirui P.,Kenya Professional Safari Guides Association | Monadjem A.,University of Swaziland | Thomsett S.,Ornithology Section | Githiru M.,Ornithology Section
Ostrich | Year: 2010

Vulture populations have declined globally as well as regionally within Africa. Little is known about the status of the African White-backed Vulture Gyps africanus in Kenya, but ongoing studies indicate that its population has declined over the last two decades. A total of 32 African White-backed Vulture nests were monitored in the Masai Mara National Reserve over a five-year period between 2003 and 2007. Mean nesting success was 59%, which is comparable to that of populations from southern Africa. Nearest neighbour distances were significantly closer in wooded habitats ('trees and shrubs savanna') than in more open grassland habitats ('open low shrubs'). Based on nearest neighbour distances, the estimated total breeding population within the Masai Mara National Reserve is 1 106 pairs, a figure that may be an overestimate and requires groundtruthing. Collecting baseline data on numbers of breeding pairs and regular nest monitoring are essential in order to assess the impact of various threats to vultures in Kenya, which include growing threats (elephant-mediated habitat disturbance and fire) as well as emerging threats (such as poisoning with the carbamate-based pesticide Furadan™). © NISC (Pty) Ltd.

Kendall C.J.,Princeton University | Virani M.Z.,Ornithology Section | Hopcraft J.G.C.,Frankfurt Zoological Society | Bildstein K.L.,Acopian Center for Conservation Learning | Rubenstein D.I.,Princeton University
PLoS ONE | Year: 2014

The ongoing global decline in vulture populations raises major conservation concerns, but little is known about the factors that mediate scavenger habitat use, in particular the importance of abundance of live prey versus prey mortality. We test this using data from the Serengeti-Mara ecosystem in East Africa. The two hypotheses that prey abundance or prey mortality are the main drivers of vulture habitat use provide alternative predictions. If vultures select areas based only on prey abundance, we expect tracked vultures to remain close to herds of migratory wildebeest regardless of season. However, if vultures select areas where mortality rates are greatest then we expect vultures to select the driest regions, where animals are more likely to die of starvation, and to be attracted to migratory wildebeest only during the dry season when wildebeest mortality is greatest. We used data from GSM-GPS transmitters to assess the relationship between three vulture species and migratory wildebeest in the Mara-Serengeti ecosystem. Results indicate that vultures preferentially cluster around migratory herds only during the dry season, when herds experience their highest mortality. Additionally during the wet season, Ruppell's and Lappet-faced vultures select relatively dry areas, based on Normalized Difference Vegetation Index, whereas White-backed vultures preferred wetter areas during the wet season. Differences in habitat use among species may mediate coexistence in this scavenger guild. In general, our results suggest that prey abundance is not the primary driver of avian scavenger habitat use. The apparent reliance of vultures on non-migratory ungulates during the wet season has important conservation implications for vultures in light of on-going declines in non-migratory ungulate species and use of poisons in unprotected areas. © 2014 Kendall et al.

Callens T.,Ghent University | Galbusera P.,Center for Research and Conservation | Matthysen E.,University of Antwerp | Durand E.Y.,University of California at Berkeley | And 3 more authors.
Molecular Ecology | Year: 2011

Habitat fragmentation can restrict geneflow, reduce neighbourhood effective population size, and increase genetic drift and inbreeding in small, isolated habitat remnants. The extent to which habitat fragmentation leads to population fragmentation, however, differs among landscapes and taxa. Commonly, researchers use information on the current status of a species to predict population effects of habitat fragmentation. Such methods, however, do not convey information on species-specific responses to fragmentation. Here, we compare levels of past population differentiation, estimated from microsatellite genotypes, with contemporary dispersal rates, estimated from multi-strata capture-recapture models, to infer changes in mobility over time in seven sympatric, forest-dependent bird species of a Kenyan cloud forest archipelago. Overall, populations of sedentary species were more strongly differentiated and clustered compared to those of vagile ones, while geographical patterning suggested an important role of landscape structure in shaping genetic variation. However, five of seven species with broadly similar levels of genetic differentiation nevertheless differed substantially in their current dispersal rates. We conclude that post-fragmentation levels of vagility, without reference to past population connectivity, may not be the best predictor of how forest fragmentation affects the life history of forest-dependent species. As effective conservation strategies often hinge on accurate prediction of shifts in ecological and genetic relationships among populations, conservation practices based solely upon current population abundances or movements may, in the long term, prove to be inadequate. © 2011 Blackwell Publishing Ltd.

PubMed | Ornithology Section and Dedan Kimathi University of Technology
Type: | Journal: Biodiversity data journal | Year: 2016

Environmental degradation is a major threat facing ecosystems around the world. In order to determine ecosystems in need of conservation interventions, we must monitor the biodiversity of these ecosystems effectively. Bioacoustic approaches offer a means to monitor ecosystems of interest in a sustainable manner. In this work we show how a bioacoustic record from the Dedan Kimathi University wildlife conservancy, a conservancy in the Mount Kenya ecosystem, was obtained in a cost effective manner. A subset of the dataset was annotated with the identities of bird species present since they serve as useful indicator species. These data reveal the spatial distribution of species within the conservancy and also point to the effects of major highways on bird populations. This dataset will provide data to train automatic species recognition systems for birds found within the Mount Kenya ecosystem. Such systems are necessary if bioacoustic approaches are to be employed at the large scales necessary to influence wildlife conservation measures.We provide acoustic recordings from the Dedan Kimathi University wildlife conservancy, a conservancy in the Mount Kenya ecosystem, obtained using a low cost acoustic recorder. A total of 2701 minute long recordings are provided including both daytime and nighttime recordings. We present an annotation of a subset of the daytime recordings indicating the bird species present in the recordings. The dataset contains recordings of at least 36 bird species. In addition, the presence of a few nocturnal species within the conservancy is also confirmed.

Kendall C.J.,Princeton University | Virani M.Z.,Ornithology Section
Journal of Raptor Research | Year: 2012

We used GSM-GPS transmitters to study mortality in three species of vultures in Masai Mara National Reserve, Kenya. GSM-GPS transmitters were a cost-effective alternative to traditional satellite telemetry. In combination with data from a wing-tagging study, GSM-GPS units provided evidence of high mortality in African vultures, particularly White-backed Vultures (Gyps africanus) and Lappet-faced Vultures (Torgos tracheliotos). Four of seventy-eight wing-tagged vultures were reported dead in a 6-yr period following attachment, whereas 4 of 17 GSM-GPS-tagged vultures were confirmed dead within a year of attachment, based on collection of dead bird or unit, indicating annual mortality of up to 33% for some species in East Africa. Poisoning was confirmed as the cause of death in four of these cases and was suspected in the majority of deaths recorded. © 2012 The Raptor Research Foundation, Inc.

Kendall C.,Princeton University | Virani M.Z.,Ornithology Section | Kirui P.,Kenya Professional Safari Guides Association | Thomsett S.,Ornithology Section | Githiru M.,Ornithology Section
Condor | Year: 2012

Because of the high, albeit seasonal, availability of carcasses, the Mara-Serengeti ecosystem, Ken ya, has a high diversity of scavengers, leading to considerable competition between species. from patterns of occurrence of vultures at 163 carcasses over an 8-year period in the Masai Mara National Reserve, we were able to identify some mechanisms that may reduce competition. Species are associated on the basis of similar dietary needs and beak morphology, and they are highly interdependent, showing little evidence of disassociation. Social vultures (genus Gyps) dominated the vulture scene at the reserve; they were more abundant at carcasses when migratory ungulates were present in the dry season, when more carcasses are likely to be available, than when migratory ungulates were absent. In addition, regardless of the predator's identity, presence of a predator reduced the number of vultures, suggesting that vultures prefer carrion not killed by predators where available. Comparisons between past and current counts of carcasses suggest a substantial shift in Gyps vultures with an increase in the relative abundance of Rüppell's Vulture (G. rueppellii) with respect to that of the White-backed Vulture (G. africanus). In addition, our findings suggest that as changing land use in the Mara-Serengeti ecosystem leads to reductions of large ungulates, social vultures will be the most adversely affected. © The Cooper Ornithological Society 2012.

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.

Otieno P.O.,Maseno University | Lalah J.O.,Maseno University | Virani M.,Ornithology Section | Jondiko I.O.,Maseno University | Schramm K.-W.,Helmholtz Center for Environmental Research
Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes | Year: 2010

This study was undertaken to determine the concentrations of carbofuran residues in water, soil and plant samples from selected sites in the farmlands in Kenya and to demonstrate the impact of Furadan use on the local environment. Soil, water and plant samples obtained from agricultural farmlands where the technical formulation Furadan has been used extensively showed high environmental contamination with concentrations of carbofuran and its two toxic metabolites 3-hydroxycarbofuran and 3-ketocarbofuran, separately, ranging from 0.010-1.009 mg/kg of dry surface soil, 0.005-0.495 mg/L in water samples from two rivers flowing through the farms and bdl-2.301 mg/L in water samples from ponds and dams located close to the farms. Maize plant samples contained these residues in concentrations ranging from 0.04-1.328 mg/kg of dry plant tissue. The significantly high concentration levels of carbofuran and its metabolites, 3-ketocarbofuran and 3-hydroxycarbofuran, found in various matrices demonstrate that Furadan was used extensively in the two areas and that there was environmental distribution and exposure of residues in water which posed risks when used for domestic purposes or as drinking water for animals in two wildlife conservancies where the dams and ponds are located. Surface soil contamination was also high and posed risks through run-off into the dams and rivers as well as through secondary exposure to small birds and mammals. © Taylor & Francis Group, LLC.

Cox S.C.,University College London | Cox S.C.,Bird Group | Prys-Jones R.P.,Bird Group | Habel J.C.,TU Hamburg - Harburg | And 2 more authors.
Molecular Ecology | Year: 2014

The Eastern Afromontane biodiversity hotspot composed of highly fragmented forested highlands (sky islands) harbours exceptional diversity and endemicity, particularly within birds. To explain their elevated diversity within this region, models founded on niche conservatism have been offered, although detailed phylogeographic studies are limited to a few avian lineages. Here, we focus on the recent songbird genus Zosterops, represented by montane and lowland members, to test the roles of niche conservatism versus niche divergence in the diversification and colonization of East Africa's sky islands. The species-rich white-eyes are a typically homogeneous family with an exceptional colonizing ability, but in contrast to their diversity on oceanic islands, continental diversity is considered depauperate and has been largely neglected. Molecular phylogenetic analysis of ∼140 taxa reveals extensive polyphyly among different montane populations of Z. poliogastrus. These larger endemic birds are shown to be more closely related to taxa with divergent habitat types, altitudinal distributions and dispersal abilities than they are to populations of restricted endemics that occur in neighbouring montane forest fragments. This repeated transition between lowland and highland habitats over time demonstrate that diversification of the focal group is explained by niche divergence. Our results also highlight an underestimation of diversity compared to morphological studies that has implications for their taxonomy and conservation. Molecular dating suggests that the spatially extensive African radiation arose exceptionally rapidly (1-2.5 Ma) during the fluctuating Plio-Pleistocene climate, which may have provided the primary driver for lineage diversification. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Loading Ornithology Section collaborators
Loading Ornithology Section collaborators