Research Article
Avian inventory and key species of the Masoala Peninsula, Madagascar
- R. Thorstrom, R. T. Watson
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- Published online by Cambridge University Press:
- 11 May 2010, pp. 99-115
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From mid-September 1993 to February 1994 avian species were inventoried at eight sites selected to sample the major biogeographic areas and threatened habitats of Masoala Peninsula of north-eastern Madagascar. The sites ranged from 10 to 1100 m elevation. Three forest types were inventoried: six sites included primary lowland rainforest (0–700 m), one site was characterized as moist montane forest (above 700 m), and one site was classified as littoral forest. Bird species and distribution were sampled using point counts and line transects, tree observations and opportunistic sightings; 85 avian species were detected. Line transects were the most productive technique for number of species detected. Twenty-four detected species were shared by all inventory sites. Six threatened and six near-threatened species were observed with notes on their ecology and behaviour. One endangered species, the Madagascar Serpent-eagle Eutriorchis astur, was first observed along a forest edge and then sighted several times at forest interior sites, suggesting that this secretive endangered raptor is not as rare as previously thought. Another species of indeterminate status, the Madagascar Red Owl Tyto soumagnei, was discovered by two villagers near one inventory site in modified habitat. Several rare and near-threatened species were found to be common throughout Masoala Peninsula: Scaly Ground-roller Brachypteracias squamiger, Short-legged Ground-roller B. leptosomus, Red-breasted Coua Cona serriana, Brown Mesite Mesitornis unicolor, Helmet Vanga Euryceros prcvostii, Bernier's Vanga Oriolia bernieri and Rand's Warbler Randia pseudozosterops; the last was only found along pristine riverine habitat. Three species were detected only at the high elevation montane forest: Grey-crowned Greenbul Phyllastrephus cinereiceps, Forest Rock-thrush Pseudocossyphus sharpei and Madagascar Brush-warbler Nesillas typica. Forest degradation from subsistence agriculture, shifting cultivation and fuelwood collecting threatens natural resources and biodiversity but conservation and development efforts can provide alternatives to meet the needs of the local people.
Depuis la moitié du mois de septembre 1993 jusqu'au février 1994, nous avons inventorié la communauté avienne dans huit sites représentant la grande partie des habitats naturels de la Presqu'île de Masoala, Nord-Est de Madagascar. Ces sites ont des altitudes comprises entre 10 et 1100 m. Trois types de forêt ont été inventoriés: six sites de forêt primaire de basse altitude (0–700 m), un site considéré comme forêt humide de montagne (plus de 700 m), et le dernier classé comme for^t littorale. L'échantillonage était fait par point d'écoute et ligne de transect. Certains grands arbres ont été utilisés comme poste d'observation. Quatre-vingts cinq espèces d'oiseaux étaient détectées. Vingt quatre espèces sont communes aux sites inventoriés. Six espèces classées comme menacé et six autres en train de l'être sont observées avec des notes sur leur écologie et comportement. Une espèce en danger, l'Aigle serpentaire Eutriorchis astur, était observée pour la première fois le long d'une bordure forestière et puis vue plusieurs fois en pleine forèt. Ce qui suggère que cette espèce en danger et trèsdiscrète n'est pas très rare comme on a toujours pensé. Une autre espèce de statut indéterminé, l'Effraie de Soumagne Tyto soumagnei était découverte par deux villageois près d'un site d'inventaire dans un habitat dégradé. Quelques espèces rares et en train d'être menacées semblaient communes dans toute la Presqu'île de Masoala: Rollier terrestre écailleux Brachyptcracias squamiger, Rollier terrestre leptosome B. leptosomus, Coua de Serre Couci scrriana, Mésite unicolore Mesitornis unicolor, Eurycère de Prévost Euryceros prevostii, Oriolie de Bernier Oriolia bernieri et la Fauvette de Rand Randia pseudozosterops. Cette dernière se trouve seulement dans les habitats longeant les cours d'eau. Trois espèces sont seulement observées dans une forêt de haute altitude de montagne: Bulbul a tête grise Phyllastrepluis cinereiceps, Merle de roche de forêt Pseudocossyphus sharpei et la Fauvette de Madagascar Nesillas typica. La dégradation forestière causée par le besoin de surface cultivable, la culture itinérante et la collecte de bois de chauffe, menacent les ressources naturelles et la biodiversité du milieu. Seulement, la conservation en parallèle avec des efforts de développement peut fournir une alternative aux besoins de la population locale. Ceci est parmi les objectifs du Projet Masoala; cherchant des alternatives pour la population locale en même temps que la création d'un Pare National qui pourrait protéger une grande partie de bloc forestier de basse altitude de Madagascar, plus de 210.000 hectares.
The avifauna of the Beni Biological Station, Bolivia
- Robin C. Brace, Jon Hornbuckle, James W. Pearce-Higgins
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- Published online by Cambridge University Press:
- 11 May 2010, pp. 117-159
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An annotated compendium of all those bird species known to have occurred in the lowland “Man and Biosphere” Beni Biological Station (B.B.S.) reserve is provided. Previous checklists are reviewed, together with sightings accumulated over the 1992–1995 period during which approximately 70 new species have been added to the reserve inventory, bringing the total to 478. Occurrence across the 12 delineated habitats, relative abundance and sighting documentation are given for each species. The avifauna of the B.B.S. is mixed biogeographically; in addition to a substantial component of lowland birds widespread throughout South America, it is composed of Amazonian, cerrado and chaco elements also. Representation from the Bolivian Yungas is minimal. Significantly, no less than four threatened and 15 near-threatened species have occurred, including the little known Bolivian endemic Unicoloured Thrush Turdus haplochrous, and the enigmatic White-winged Nightjar Caprimulgus candicans, known until recently only from Emas National Park (Brazil). Short accounts are provided detailing records of all of these species. Birds of the reserve core, consisting largely of humid tropical forest formations inundated during the austral summer, appear not to be subjected currently to any serious environmental degradation, although some subsistence clearance by Chimane Indians in the northern reaches of the reserve gives some cause for concern. Of much greater import, however, are changes occurring outside the confines of the B.B.S. These include increasing urbanization immediately to the west (and associated road upgrading) and forest fragmentation to the south brought about by logging. The latter is especially worrying because linkage of the B.B.S. forest block to surrounding forest is already physically tenuous, and therefore it is imperative that future logging activities be geared to minimize isolation occurring and the damaging restriction of gene flow. Monitoring in rainforest immediately south of the reserve should become routine to warn of putative avifaunal impoverishments. Extensive surveying of the 2,500-ha El Porvenir éstancia (savanna and related forest islands) due to be assimilated shortly into the B.B.S., which constitutes less than 2% of the area under consideration, has shown that it is used by no less than three threatened and up to nine near-threatened species. In the absence of data relating to other savanna areas (c. 15%) at present, the exact status of each species at the B.B.S. remains imprecise and begs for further research to be undertaken. Unfortunately, present management of the El Porvenir savanna is not conducive to the long-term maximization of populations of these species, several of which have local strongholds in this part of Beni. We recommend that the current policy of cattle ranching adopted by this éstancia should cease or be reduced dramatically, to minimize grazing and trampling damage, and that measures should be taken to reduce incursions of fires started wilfully in neighbouring properties. The Academia Nacional de Ciencias de Bolivia, which administers the reserve, should be encouraged to safeguard and enhance the savanna complement further by ensuring that the impending ratification of El Porvenir proceeds as quickly as possible, and by purchasing additional tracts of land to the south of the present southern reserve boundary, where feasible. Such actions should not only secure the future of the biota of the savanna habitat within the B.B.S. but also should ameliorate the degree of isolation which has occurred already by preserving the “curiches” (former river beds) and forest islands which act as access corridors for forest-dwelling and other birds.
Newly discovered breeding sites of Olrog's Gull Larus atlanticus in Argentina
- Pablo Yorio, Gabriel Punta, Daniel Rabano, Fabian Rabuffetti, Gonzalo Herrera, Jose Saravia, Pablo Friedrich
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- Published online by Cambridge University Press:
- 11 May 2010, pp. 161-165
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Olrog's Gull Larus atlanticus is a threatened and endemic species to the Argentine Atlantic coast. We present information on seven new colonies and update information on known colonies obtained during 1992–1995. Five of the new colonies were in southern Buenos Aires and two in southern Chubut. Total population size, including already known colonies, was estimated at 2,300 breeding pairs. All colonies were located on islands and islets and were associated with breeding Kelp Gulls Larus dominicanus. The new colonies extend the known breeding range of Olrog's Gull to the north and increase the overall known population size. However, the aerial survey also showed that two colonies found in 1990 no longer exist. Almost 40% of the total breeding population breed within the Bahía Blanca estuary, an area currently subject to intense human pressure. Olrog's Gull is still a species with restricted distribution and low population size. We suggest conservation actions needed to adequately protect this threatened species.
Trends in populations of Red-legged Kittiwake Rissa brevirostris, a Bering Sea endemic
- G. Vernon Byrd, Jeffrey C. Williams, Yuri B. Artukhin, Peter S. Vyatkin
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- Published online by Cambridge University Press:
- 11 May 2010, pp. 167-180
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The Red-legged Kittiwake Rissa brevirostris is a small gull which is restricted to four breeding locations, all in the Bering Sea (Pribilof Islands, Bogoslof Island, Buldir Island, and the Commander Islands). In the mid-1970s, when the earliest counts were made at most sites, approximately 260,000 birds were present at breeding colonies. Subsequent counts indicated that populations at Bogoslof and Buldir had increased by the early 1990s. Data for the Commander Islands were inadequate to make strong conclusions about trends but there were no indications of substantial change between the 1970s and 1990s. In contrast, Red-legged Kittiwakes have declined in the Pribilof Islands by approximately 50% since the mid-1970s, a matter of concern because this island group once contained more than 80% of the world's population. Research is needed to determine causes for declines in Red-legged Kittiwakes and population monitoring should continue to provide a basis for conservation measures.
The conservation status of birds on the Cordillera de Colán, Peru
- C. W. N. Davies, R. Barnes, S. H. M. Butchart, M. Fernandez, N. Seddon
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- Published online by Cambridge University Press:
- 11 May 2010, pp. 181-195
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In July and August 1994, we surveyed two areas in the south of the Cordillera de Colán, Amazonas department, Peru, above the north bank of the río Utcubamba. We found a high rate of deforestation, with trees being felled for timber, forest being cleared for the cultivation of cash crops, and elfin forest being burned for pasture. Most of the forest on the mountain range may have been cleared in 10 years. We recorded a number of important bird species, highlighting the significance of the area for the conservation of biodiversity; globally threatened birds included Peruvian Pigeon Columba oenops, Military Macaw Ara militaris and Royal Sunangel Heliangelus regalis. Elfin forest is under particular threat in the area, but probably still holds species such as Long-whiskered Owlet Xenoglaux loweryi. We recommend that a protected area containing areas of cloud-forest and elfin forest be established on the Cordillera de Colán.
Front matter
BCI Volume 7 issue 2 Cover and Front matter
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- Published online by Cambridge University Press:
- 11 May 2010, pp. f1-f2
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Back matter
BCI Volume 7 issue 2 Cover and Back matter
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- Published online by Cambridge University Press:
- 11 May 2010, pp. b1-b4
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