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Iwajomo S.B.,AP Leventis Ornithological Research Institute | Hedenstrom A.,Lund University
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.

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.

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.

Effiom E.O.,Lund University | Nunez-Iturri G.,University of Illinois at Chicago | Smith H.G.,Lund University | Ottosson U.,AP Leventis Ornithological Research Institute | Olsson O.,Lund University
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.

Barshep Y.,University of Cape Town | Barshep Y.,AP Leventis Ornithological Research Institute | Underhill L.G.,University of Cape Town | Balachandran S.,Bombay Natural History Society | Pearson D.J.,Lupin Close Reydon
Ardea | Year: 2013

We investigated the adaptations of primary moult to conditions on the nonbreeding areas in the Curlew Sandpiper Calidris ferruginea, an Arctic breeding, long-distance migratory wader (shorebird). Parameters of moult (start date, duration, and standard deviation) and how they are affected by rainfall patterns were estimated using and extension of the Underhill-Zucchini (1988) moult models which allows the inclusion of covariates. The estimated start date and duration of moult in Kenya was 2 October and 128 days, respectively; start date was negatively correlated with the rainfall in June. In India, the estimated start date of moult was 15 August, duration 107 days and start of moult was positively correlated to the rainfall in August. Circumstantial evidence also suggests that the rate of growth of the primaries was affected by food supply at the nonbreeding areas. The timing of moult to coincide with rainfall periods is, perhaps, an adaptation to carry out this energy demanding activity during periods of food abundance. This study shows that in these populations of the Curlew Sandpiper, the timing of moult is a direct response to environmental variation and might be used to measuring the impacts of climate change on life-history traits of migratory birds.

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