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Iwajomo S.B.,Ap Leventis Ornithological Research Institute | Hedenstrom A.,Lund University | Hedenstrom A.,Ottenby Bird Observatory
Ringing and Migration | Year: 2011

Current knowledge of the migration of the Common Sandpiper Actitis hypoleucos is still limited. The species has been ringed at Ottenby Bird Observatory, southeast Sweden, since 1947, allowing for analyses of long-term and seasonal trends. We analysed trapping data for 1,942 adults and 3,290 juveniles with respect to patterns in phenology, morphometrics, and fuel load. We used fuel loads to estimate potential flight ranges. The number of adult birds trapped increased significantly over the years, whereas juveniles declined. Median passage date was 27 July and 7 August for adult and juvenile birds respectively, and juveniles showed a significant advancement in median passage date. Mean fuel loads were 28.8% and 27.8% of lean body mass (LBM) for adult and juvenile birds respectively, while maximum fuel load was as high as 98.7% in juveniles and 105.4% in adults. Fuel load increased significantly with date in juveniles but declined in adults. Advancement in passage of juvenile birds over the year is possibly due to climate change. Also, the average adult and juvenile are theoretically capable of a direct flight to central France; a major recovery area. Fuel load patterns suggest that in autumn, the two age classes use different migration strategies. © 2011 British Trust for Ornithology.


Barshep Y.,University of Cape Town | Barshep Y.,Ap Leventis Ornithological Research Institute | Minton C.,165 Dalgetty Road | Underhill L.G.,University of Cape Town | And 2 more authors.
Ardea | Year: 2011

The population moult parameters, yearly onset of moult and sex-specific schedule of moult in relation to breeding success, and pattern of feather mass growth were examined in a population of Curlew Sandpipers Calidris ferruginea that migrate to northwest Australia. The mean start date of moult was 18 September, and it lasted on average 129 days. No significant variation in duration of moult was detected and feather mass was deposited at a constant rate. The yearly onset of moult was positively correlated with the proportion of first year (juvenile) birds: the mean start date of moult in good breeding years was 25 September, ten days later than mean start date of moult in poor breeding years, being 15 September. Males generally started moult five days earlier than females. The mean moult start date of males was five days earlier in poor breeding years compared to good breeding years, while the moult of females was 11 days earlier in poor breeding years compared to good breeding years. In Curlew Sandpipers the timing of post-breeding migration is advanced in bad breeding seasons, which explains the observed correlation between breeding success and the timing of moult in non-breeding areas.


Blackburn E.,University of St. Andrews | Blackburn E.,Ap Leventis Ornithological Research Institute | Cresswell W.,University of St. Andrews | Cresswell W.,Ap Leventis Ornithological Research Institute
Bird Study | Year: 2016

ABSTRACT: Wintering Northern Wheatears Oenanthe oenanthe in the Sahel region of Northern Nigeria held small (approximately 70 m diameter) distinct territories during the study period, and territory size did not differ between adult and first winter birds. Evidence suggests that Wheatears may maintain small territories for a significant duration of the winter, similar to many other migrants. © 2016 British Trust for Ornithology.


Wilson J.M.,SOI Ltd | Wilson J.M.,AP Leventis Ornithological Research Institute | Cresswell W.,University of St. Andrews | Cresswell W.,AP Leventis Ornithological Research Institute
Ostrich | Year: 2010

Palearctic migrant birds are declining, including the Northern Wheatear, and some of the causes of these declines are likely to be operating on their wintering grounds in Africa. We examined seasonal and spatial variation in wintering densities of Northern Wheatears in northern Nigeria, and explored the species' habitat associations on the wintering grounds to assess the likely effects of habitat change in the Sahel on this species. Densities of Northern Wheatears across northern Nigeria were calculated from point count data gathered during two winters (2000 and 2001) using Distance software, and the relationships between Wheatear presence and habitat variables collected from the same points were explored using general linear models. During mid-winter and early spring, densities of Northern Wheatears peaked, with significantly more birds present in western than eastern study sites. The probability of wheatear occurrence was correlated with Balanites and Salvadora tree density and mean tree height. The Northern Wheatear may benefit from the conversion of woodland habitats in the Sahel to more open savanna. However, sites with very low tree densities showed low probabilities of Northern Wheatears being present, suggesting excessive tree clearance may have a negative effect upon the species. © NISC (Pty) Ltd.


Sunday Imong I.,AP Leventis Ornithological Research Institute
Bird Conservation International | Year: 2010

The mountains of south-eastern Nigeria are a western extension of the Cameroon mountain range, which is classified as an endemic bird area (EBA). Unlike its eastern extension in Cameroon, most of the ornithological surveys in the western extension of the Cameroon highlands in Nigeria have produced only limited checklists and inventories. There is a clear need for quantitative baseline data so that conservation problems can be identified. Twenty line transects covering a total transect length of 28.8 km were used to survey five sites (Afi Mountain Wildlife Sanctuary, Oban Division and Okwangwo Division of Cross River National Park, Sankwala Mountains and Mbe Mountains) in the westernmost extension of the Cameroon Mountains EBA in south-eastern Nigeria. Vegetation measurements were taken to control for the potential confounding effect of variation in vegetation density and structure on detectability of birds between sites. The 193 bird species recorded in Afi, 158 in Sankwala, 124 in Oban, 100 in Mbe and 73 in Okwangwo Division included most of the Cameroon highlands restricted range species. The results show that the mountains of south-eastern Nigeria are important parts of the Cameroon EBA, particularly Afi Mountain Wildlife Sanctuary. However these sites are threatened by fire and livestock grazing on the hilltops, shifting agriculture on the hillsides and lowlands, and logging for timber in some parts, as well as wildlife hunting for bushmeat. Copyright © BirdLife International 2010.


Molokwu M.N.,Ap Leventis Ornithological Research Institute | Molokwu M.N.,Lund University | Nilsson J.,Lund University | Ottosson U.,Ap Leventis Ornithological Research Institute | And 2 more authors.
Oecologia | Year: 2010

Birds from semi-arid regions may suffer dehydration during hot, dry seasons with low food availability. During this period, both energetic costs and water requirements for thermoregulation increase, limiting the scope of activity. For granivorous birds feeding on dry seeds, this is a major challenge and availability of water may affect the value of food. Water availability could (1) increase the value of a food patch when the surrounding environment is poor, due to an increase in the marginal value of energy, and (2) increase the value of the entire environment to the forager when environmental quality increases, due to an increase in the marginal value of time. We aimed to test this by measuring giving-up densities (GUDs, remaining food densities after foraging) of granivorous birds in the presence or absence of filled water pots, at different seasons differing in background food and water availability. We predicted that GUDs will increase with water provision during the dry season with moderate food, but in the early wet season with low food and water availability, GUDs will decrease with water provision. Later in the wet season, our experimental addition of water should have no effect. During seasons with low water availability but differing in food availability, results confirmed our predictions. However, when water became more abundant as the wet season progressed, birds still foraged more intensely during days with added water. In all seasons, birds fed more intensely in cover than in exposed areas, suggesting that predation risk rather than heat influenced microhabitat selection. © 2010 Springer-Verlag.


Hulme M.F.,University of St. Andrews | Hulme M.F.,AP Leventis Ornithological Research Institute | Cresswell W.,University of St. Andrews | Cresswell W.,AP Leventis Ornithological Research Institute
Ibis | Year: 2012

The Whinchat Saxicola rubetra is an Afro-Palaearctic migrant undergoing widespread population decline. Whinchats winter in West Africa but there are almost no data on their habitat use and behaviour there that may help to explain the cause of this decline. We measured the density of Whinchats, the habitat characteristics associated with their occurrence on farmland, and the relationships between behavioural and habitat variation on farmland around Jos, central Nigeria, over three winters. Whinchats occurred in many fields harvested in the dry season, the density at three sites varying from 0.03 to 0.43 birds/ha, but they were absent at a fourth site. Whinchats were less likely to be found in farmland without particular crops (e.g. structural stem crops such as maize and millet), with more trees, lower amounts of short vegetation (grass, weeds, crops and crop stubble less than 10 cm in height), and higher amounts of medium vegetation (coverage of vegetation 10-100 cm in height) and litter (dead, unburned, vegetation on the ground). Whinchat abundance in areas of farmland where they were present was independent of most variables considered, but density was higher where there was more short vegetation cover. Foraging behaviour did not vary significantly between farmland habitats. All predictors were consistent between season, years and across sites. The presence/absence model was very poor at predicting presence and there were no strong predictors of abundance or foraging variation. This is consistent with a species well below carrying capacity within its environment so that many suitable areas do not have birds present and there is little aggregation at better sites. Overall, Whinchats were abundant and appeared to have plentiful habitat; densities have probably increased alongside the intensification of agriculture (presence of fallow farmland, short vegetation and structural crops). The results suggest that West African farmland in the dry season can support large numbers of Whinchats and that recent population declines in Europe are unlikely to be caused primarily by lack of suitable wintering habitat. © 2012 The Authors Ibis © 2012 British Ornithologists' Union.


Nilsson J.-A.,Lund University | Molokwu M.N.,Fauna and Flora International | Molokwu M.N.,Ap Leventis Ornithological Research Institute | Olsson O.,Lund University
PLoS ONE | Year: 2016

Organisms in hot environments will not be able to passively dissipate metabolically generated heat. Instead, they have to revert to evaporative cooling, a process that is energetically expensive and promotes excessive water loss. To alleviate these costs, birds in captivity let their body temperature increase, thereby entering a state of hyperthermia. Here we explore the use of hyperthermia in wild birds captured during the hot and dry season in central Nigeria. We found pronounced hyperthermia in several species with the highest body temperatures close to predicted lethal levels. Furthermore, birds let their body temperature increase in direct relation to ambient temperatures, increasing body temperature by 0.22°C for each degree of increased ambient temperature. Thus to offset the costs of thermoregulation in ambient temperatures above the upper critical temperature, birds are willing to let their body temperatures increase by up to 5°C above normal temperatures. This flexibility in body temperature may be an important mechanism for birds to adjust to predicted increasing ambient temperatures in the future. © 2016 Nilsson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Effiom E.O.,Lund University | Effiom E.O.,Cross River State Forestry Commission | Nunez-Iturri G.,University of Illinois at Chicago | Smith H.G.,Lund University | And 2 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2013

To assess ecological consequences of bushmeat hunting in African lowland rainforests, we compared paired sites, with high and low hunting pressure, in three areas of southeastern Nigeria. In hunted sites, populations of important seed dispersers-both small and large primates (including the Cross River gorilla, Gorilla gorilla diehli)-were drastically reduced. Large rodents were more abundant in hunted sites, even though they are hunted. Hunted and protected sites had similar mature tree communities dominated by primate-dispersed species. In protected sites, seedling communities were similar in composition to the mature trees, but in hunted sites species with other dispersal modes dominated among seedlings. Seedlings emerging 1 year after clearing of all vegetation in experimental plots showed a similar pattern to the standing seedlings. This study thus verifies the transforming effects of bushmeat hunting on plant communities of tropical forests and is one of the first studies to do so for the African continent. © 2013 The Author(s) Published by the Royal Society. All rights reserved.


PubMed | Lund University, Chinese Academy of Agricultural Sciences, AP Leventis Ornithological Research Institute and Gothenburg University
Type: | Journal: Molecular phylogenetics and evolution | Year: 2016

The avian genus Calandrella (larks) was recently suggested to be non-monophyletic, and was divided into two genera, of which Calandrella sensu stricto comprises 4-5 species in Eurasia and Africa. We analysed mitochondrial cytochrome b (cytb) and nuclear Restriction-site Associated DNA (RAD) sequences from all species, and for cytb we studied 21 of the 22 recognised subspecies, with the aim to clarify the phylogenetic relationships within the genus and to compare large-scale nuclear sequence patterns with a widely used mitochondrial marker. Cytb indicated deep splits among the currently recognised species, although it failed to support the interrelationships among most of these. It also revealed unexpected deep divergences within C. brachydactyla, C. blanfordi/C. erlangeri, C. cinerea, and C. acutirostris. It also suggested that both C. brachydactyla and C. blanfordi, as presently circumscribed, are paraphyletic. In contrast, most of the many subspecies of C. brachydactyla and C. cinerea were unsupported by cytb, although two populations of C. cinerea were found to be genetically distinct. The RAD data corroborated the cytb tree (for the smaller number of taxa analysed) and recovered strongly supported interspecific relationships. However, coalescence analyses of the RAD data, analysed in SNAPP both with and without an outgroup, received equally strong support for two conflicting topologies. We suggest that the tree rooted with an outgroup - which is not recommended for SNAPP - is more trustworthy, and suggest that the reliability of analyses performed without any outgroup species should be thoroughly evaluated. We also demonstrate that degraded museum samples can be phylogenetically informative in RAD analyses following careful bioinformatic treatment. We note that the genus Calandrella is in need of taxonomic revision.

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