bluuebunny/crossref_metadata_2025_split huggingface dataset:
Habitat exploitation by landbirds in the changing Western Samoan environment
Authors: Evans S. M. , Fletcher F. J. C. , Loader P. J. , Rooksby F. G. 
Published: May 2010

SummaryThe avifauna of Western Samoa is dominated by indigenous species, including several endemic ones. They are primarily birds of the rainforest and, since the islands have already suffered severe loss of this habitat and there is likely to be increased pressure on it in the future, their long-term prospects are not good. At present, introduced, non-native birds are not a threat to indigenous species, being confined largely to urban habitats, and there is little interaction with forest species. Several indigenous species exploit manmodified habitats, however, and it is possible that, as has occurred elsewhere, some of them may adapt fully to urban life.
The effect of rearing experience on subsequent behavioural traits in Hawaiian GeeseBranta sandvicensis: implications for the recovery programme
Authors: Marshall Ann P. , Black Jeffrey M. 
Published: May 2010

SummaryThe risk of the NeneBranta sandvicensisbecoming extinct has been minimized by the release of over 2,000 captive-reared geese, but the population (now at 500) is yet to achieve a self-sustaining status. The majority of birds released have been reared in gosling-only groups, thus missing out on the opportunity to learn social and feeding skills from adults. In this paper we test the hypothesis that rearing experience affects the subsequent behavioural traits of Nene goslings. We raised 42 goslings under four conditions: a gosling group not exposed to adults, a gosling group exposed to adults from 16 days onward, three groups in view of “foster” adults for 14 days, and four groups reared continuously by parents. All birds were eventually released into an 8 ha pen where a flock of adult Nene roamed. The method by which Nene goslings were raised had a significant effect on dominance, flock integration, and vigilance. Parent-reared birds were dominant to and more vigilant than goslings raised without parents or goslings reared in sight of adults. Parent-reared birds also integrated into the adult flock sooner than other goslings. Growth rate and final body size were not affected by rearing regime (with or without parents or foster parents). In future, managers should provide goslings with as much “parental” experience as possible in order to equip them with appropriate skills to cope once released in the wild.
Censusing Laysan Ducks Anas laysanensis: a lesson in the pitfalls of estimating threatened species populations
Authors: Marshall Ann P. 
Published: May 2010

SummaryThe Laysan Duck Anas laysanensis is a threatened species endemic to Laysan Island, Hawaü U.S.A., with a population that appears subject to severe fluctuation, although this may be attributable to different census methods. The most effective method used so far has been one that notes the ratio of marked to unmarked birds seen on censuses conducted at dusk around the central lake. In 1986 and 1987, weekly censuses were made from which population estimates were derived with the Lincoln—Petersen Index: the current population is approximately 500. The ducks were least visible during the nesting and moulting periods of spring and summer, and population estimates were significantly lower during that period in both 1986 and 1987. This phenomenon calls in doubt other estimates and probably accounts for the fluctuations noted in previous years. Thus careful attention should be given to potential problems in monitoring threatened species populations, because without a clear understanding of the ecology of the threatened species, population estimates could suggest inappropriate management measures.
Distribution, status and taxonomy of the near-threatened Black-bodied WoodpeckerDryocopus schulzi
Authors: Nieto A. Madroño , Pearman M. 
Published: May 2010

SummaryStudies of records of the Black-bodied WoodpeckerDryocopus schulzithrough literature searches, communications with ornithologists, personal observations and data from museum specimens show that the distribution of the species is basically limited to xero-phytic chaco woodlands in western Paraguay, northern and central Argentina, and southern Bolivia. Its western limit is defined by the transition zone between the chaco and the semi-humid montane forest on the east Andean slopes of southern Bolivia and north-west Argentina; in the extreme south it extends into the dry deciduous woodlands n i the sierras of Córdoba and north-eastern San Luis. The taxonomic history of the species has been chequered; we present morphological and vocal differences from its closest relative that reaffirm its specific validity. It appears to have suffered an alarming decline over much of its former range in Argentina, and appears to survive only in two isolated population centres of significant importance, in Córdoba and adjacent San Luis and in the central part of the Paraguayan chaco. The main cause of its rarity is destruction of habitat for timber extraction and expansion of agriculture and cattle-raising.El estudio de registros del Carpintero NegroDryocopus schulzimediante revision biblio-gráfica, comunicaciones de ornitólogos, observaciones personales e información adjunta a especímenes en museos, muestra que la distribución de la especie básicamente se circunscribe al bosque chaqueño de carácter xerófilo del oeste de Paraguay, norte y centro de Argentina y sur de Bolivia. Su extremo occidental alcanza la zona de transición entre el chaco y los bosques semihúmedos montanos en las sierras orientales andinas del sur de Bolivia y del noroeste argentino; en el extremo sur se extiende hasta los bosques secos decíduos de las sierras cordobesas y del noreste de San Luis. La historia taxonómica de l a especie ha sido confusa; las diferencias morfológicas y vocales que aquí se presentan y comparan con su pariente más próximo reafirman su validez específica. Parece haber sufrido una disminución preocupante en la mayor parte de su distribución original en Argentina, y quedan aparentemente tan solo un par de núcleos poblacionales aislados de cierta importancia, en Córdoba y zona adyacente de San Luis y en la zona central del chaco paraguayo. La principal causa responsable de su rarefacción se debe a la destrucción del hábitat por la explotación de los recursos madereros y a la creciente expansión de la frontera agrícola y ganadera.
The conservation status of the birds of Negros, Philippines
Authors: Brooks Thomas M. , Evans Tom D. , Dutson Guy C. L. , Anderson Guy Q. A. , Asane Desiderio C. , Timmins Robert J. , Toledo Angela G. 
Published: May 2010

SummaryOrnithological surveys were carried out in the remnant forests of the island of Negros, in the central Philippines, over five weeks in the summer of 1991. From this work it is concluded that, without the implementation of immediate conservation measures, the global extinction of four bird species is likely to occur in the near future. These are Negros Fruit-dovePtilinopus arcanus, Negros Bleeding-heartGallicolumba keayi, Writhed-billed HornbillAceros waldeniand White-throated Jungle-flycatcherKhinomyias albi-gularis. Another four species restricted to the lowlands of Negros and the adjacent island of Panay, Visayan Tarictic HornbillPenelopides panini, White-winged Cuckoo-shrikeCora-cina ostenta, Flame-templed BabblerStachyris speciosaand Visayan FlowerpeckerDicaeum (australe) haematostictum, must be considered under extreme threat, and the endemic Negros Striped-babblerStachyris nigrorumis under considerable pressure. A further twelve species listed as globally threatened are also in serious danger of extinction on Negros. This paper details the results of fieldwork and presents our conclusions and suggestions for conservation, which must include the direct preservation of the last fragments of lowland forest on the island.
Stability and changes during the twentieth century in the breeding landbirds of Tahiti (Polynesia)
Authors: Monnet Claude , Thibault Jean-Claude , Varney Albert 
Published: May 2010

SummaryThe distribution of Tahitian landbirds in the early twentieth century and at presented here together with maps. Three categories may be recognized: (1) species with a declining distribution owing to changes in habitats (Green-backed Heron), (2) stable or increased species, including local and earlier introduced species, and (3) newly introduced species (Zebra Dove, Red-vented Bulbul, Silvereye and Crimson-backed Tanager). Moreover, owing to their low population numbers, two species, the Pacific Pigeon and the Tahiti Monarch, are on the verge of extinction even if their distribution has not changed notably during this century.Les repartitions des oiseaux terrestres reproducteurs de Tahiti, au début et à la fin du 20e siècle, sont présentées sous forme de cartes. Trois catégories d'espèces sont dis-tinguées: (1) espèce dont la répartition est en déclin a la suite des modifications d'habitats (Héron vert), (2) espèces stable ou en légère augmentation, chez qui on trouve des oiseaux locaux et des oiseaux introduits, et enfin (3) les espèces introduites durant le 20e siècle (Tourterelle striée, Bulbul à ventre rouge, Zosterops à poitrine grise et Tangara cramoisi). II apparaît que deux espèces, le Carpophage du Pacifique et le Monarque de Tahiti, sont aujourd'hui très menacées, même si leur répartition n'a pas régressé d'une façon significative.
The conservation status in 1982 of the Aldabra White-throated RailDryolimnas cuvieri aldabranus
Authors: Collar N. J. 
Published: May 2010

SummaryThe Aldabra White-throated RailDryolimnas cuvieri aldabranusis confined to Middle Island (c. 7,700 birds), lie Polymnie (c. 270) and De aux Cèdres (c. 80) on Aldabra Atoll (now a World Heritage Site) in the Seychelles. It uses all available terrestrial habitats, but chiefly occurs in scrub cover and particularly in the densest types, where leaf-litter (and hence litter fauna) is richest. Its extinction on Assumption, Astove and Cosmoledo is attributable to widespread habitat loss and disturbance, and to human utilization as food; the extent to which rats and cats affect the form, which is flightless, is debatable.
Population monitoring for the flightless rail Dryolimnas cuvieri aldabranus
Authors: Hambler C. , Newing J. , Hambler K. 
Published: May 2010

SummaryThe last flightless bird of the western Indian Ocean, Dryolimnas cuvieri aldabranus survives only on Aldabra. Its population numbered some 8,000 in 1973–1976. Surveys suggest numbers remained roughly constant between 1968 and 1988 (with a fluctuation of only 4% in responses to call playback between 1983 and 1988), but distribution continued to contract. Longevity can reach over 8.5 years (but is probably lower on average), and some birds remain within 100 m of the site of ringing for at least five years. Feral predators remain a threat, and captive populations are recommended. The monitoring procedure may have value for other Gruiformes.
The effects of hurricanes on birds, with special reference to Caribbean islands
Authors: Wiley James W. , Wunderle Joseph M. 
Published: May 2010

SummaryCyclonic storms, variously called typhoons, cyclones, or hurricanes (henceforth, hurricanes), are common in many parts of the world, where their frequent occurrence can have both direct and indirect effects on bird populations. Direct effects of hurricanes include mortality from exposure to hurricane winds, rains, and storm surges, and geographic displacement of individuals by storm winds. Indirect effects become apparent in the storm's aftermath and include loss of food supplies or foraging substrates; loss of nests and nest or roost sites; increased vulnerability to predation; microclimate changes; and increased conflict with humans. The short-term response of bird populations to hurricane damage, before changes in plant succession, includes shifts in diet, foraging sites or habitats, and reproductive changes. Bird populations may show long-term responses to changes in plant succession as second-growth vegetation increases in storm-damaged old-growth forests.The greatest stress of a hurricane to most upland terrestrial bird populations occurs after its passage rather than during its impact. The most important effect of a hurricane s i the destruction of vegetation, which secondarily affects wildlife in the storm's aftermath. The most vulnerable terrestrial wildlife populations have a diet of nectar, fruit, or seeds; nest, roost, or forage on large old trees; require a closed forest canopy; have special microclimate requirements and/or live in a habitat in which vegetation has a slow recovery rate. Small populations with these traits are at greatest risk to hurricane-induced extinction, particularly if they exist in small isolated habitat fragments.Recovery of avian populations from hurricane effects is partially dependent on the extent and degree of vegetation damage as well as its rate of recovery. Also, the reproductive rate of the remnant local population and recruitment from undisturbed habitat patches influence the rate at which wildlife populations recover from damage.
The status of Gurney's Pitta Pitta gumeyi, 1987–1989
Authors: Gretton Adam , Kohler Marcus , Lansdown Richard V. , Pankhurst Tim J. , Parr John , Robson Craig 
Published: May 2010

SummaryFieldwork aimed at censusing Gumey's Pitta Pitta gumeyi in Peninsular Thailand was carried out over three field seasons. Fourteen sites were surveyed, at four of which the species was found. The main site (where it had been rediscovered in 1986) held 24–34 pairs, 12–18 of which were in the 500 ha study area. A second site held 3-6 pairs (but it is thought unlikely that this population still exists today), whilst the other two sites held only two pairs each and were thought to have negligible chances of survival. All territories were in semi-evergreen rainforest, below 150 m altitude. The current population i s probably some 20–30 pairs, with territories still being lost annually to deforestation. This is currently the total known world population; it is possible that the species may survive in southern Burma, but no recent surveys have been undertaken there. Furthermore, massive deforestation caused by Thai timber companies has been reported from Burma during 1988–1993. The interpretation of census results are discussed, particularly with reference to social organization and calling seasonality. The determined protection of the one remaining site supporting a viable population will be essential if the species is to survive into the next century.
Migration in South America: an overview of the austral system
Authors: Chesser R. Terry 
Published: May 2010

SummaryAustral migrants are species that breed in temperate areas of South America and migrate north, towards or into Amazonia, for the southern winter. Migrations among these species are the most extensive of Southern Hemisphere migrations, and the austral system represents a third major migration system, in the sense that the term has been applied to Northern Hemisphere temperate-tropical migration. The geography of South America greatly influences the austral system. Lack of east-west geographical barriers and the shape of the continent promote a pattern of partially overlapping breeding and wintering ranges. The suboscine family Tyrannidae, the tyrant-flycatchers, is the largest group of austral migrants, with other major families including Emberizidae, Anatidae, Furnariidae, Accipitridae and Hirundinidae. Tyrant-flycatchers constitute more than one-half of the passerine austral migrants and roughly one-third of total austral migrants, a taxonomic domination seen in no other global migration system. Parallels exist, however, between austral migration and the Nearctic and Palearctic systems. Many of the same families, including Hirundinidae, Anatidae and Charadriidae, exhibit similarly high degrees of migratory behavi-our in each system. Passerine migration in the austral system is similar in numbers to that of the Nearctic-Neotropical system, but species migrate shorter distances and breed in more open and scrubby habitats. Possible differences in year-round resource availability between South American and North American temperate forests, in addition to differing availability of these habitats, may contribute to the low numbers of forest-dwelling austral migrants.
Local migrations of insectivorous birds in western Mexico: implications for the protection and conservation of their habitats
Authors: Nocedal Jorge 
Published: May 2010

SummaryIn this study I present data suggesting altitudinal movements of some species of foliage-gleaning insectivorous birds and related species of an oak-pine woodland of western Mexico. These movements can be regarded as short-distance or local migrations because the species involved breed in the woodlands and forests of the Sierra Madre Occidental highlands and winter in the tropical forests of the Pacific lowlands. Nine species of insectivorous birds out of 17 breed at the study site in the mountains of southern Durango and move to the lowlands in the winter; these can be regarded as short-distance or local migrants. In Mexico tropical deciduous and semi-deciduous forests are distributed mostly in the Pacific lowlands in the states of Sinaloa, Durango, Nayarit and Jalisco. Tropical forests of the Pacific lowlands are very important as wintering grounds for both North American and local west-Mexican migrants; however, there is only one protected area in western Mexico which to some degree includes these two types of tropical forests, and it is not located in the Sierra Madre Occidental, the most important mountain range in Mexico in terms of length and area covered. In addition, these tropical forests are the northern limit of the range for many tropical species. At present, these habitats are not threatened seriously by human activities (mainly forestry and cattle-raising) but this might change at any moment. At the study site the temperate highlands of southern Durango are already under the protection of “La Michilía” Biosphere Reserve, but a proposal to enlarge the area of the reserve to include the valley of the Río Mezquital and the western slope of the valley will increase the diversity of habitats, both temperate and tropical. As a consequence more bird species, as well as other taxa, will be protected in their natural environments. Such a proposal must be supported by field evidence on actual habitat use both during the breeding and wintering season, by local and long-distance migrants, in order to assess accurately the importance of this area as a representative place of western Mexico.
The annual cycle of the White-ruffed ManakinCorapipo leucorrhoa, a tropical frugivorous altitudinal migrant, and its food plants
Authors: Rosselli Loreta 
Published: May 2010

SummaryFrugivorous White-ruffed ManakinsCorapipo leucorrhoa(Pipridae) showed pro nounced seasonal emigration from a pre-montane wet forest site (550 m) on the Atlantic slope of Costa Rica. “Resident” breeders left the area between August and October, and returned between February and April, at the onset of the breeding season. Female patterns differed from those of males primarily in later departure (October) and later return (April). I documented 57 fruit species in the diet at this locality and monitored phenology for 43 of those species, many of which were understorey members of the Melastomataceae. The emigration did not coincide with a period of local fruit shortage (relative to abundance at the same locality in other months), but the relative abundance and species composition of fruit resources in the areas to which the manakins migrated remains unknown. However, peak resources did coincide with the period in which recent fledglings would be commonest and the period during which most individuals were moulting prior ot emigration. Resources were lowest from November, when residents were absent, untilJune, well into the breeding season. Tentative evidence suggests considerable annual variation, possibly owing to differences in the timing of the rainy season. Individuals captured during the period when almost all “resident” breeders were absent (November) appeared to be transients, and were rarely recaptured. Weights differed between sexes, with females (χ = 12.5 ± 1.0) significantly heavier than males (χ = 11.1 ± 0.8). Males were lightest during the breeding season, intermediate in weight during the moulting period, and both sexes were heaviest during the migration period, when they accumulated subcutaneous fat. Females were lightest during the moult period, at which time many may also have dependent fledglings. Many other frugivores and nectarivores may engage in similar altitudinal migrations. Even where altitudinal migration is not possible, birds might migrate to other habitats with different fruit resources or phenologies. The design of nature reserves should accommodate the possibility of significant altitudinal (or cross-habitat) migration for many species of frugivores and nectarivores.
Nearctic avian migrants in coffee plantations and forest fragments of south-western Guatemala
Authors: Vannini Jay P. 
Published: May 2010

SummaryHabitats at intermediate and upper elevations of the volcanic Cordillera of southwestern Guatemala harbour a diverse terrestrial vertebrate fauna that includes at least 423 avian species, 108 of which are known to be Nearctic migrants, and 43 of which are known or suspected to have both resident and long-distance migrant populations. During the course of floral and faunal inventories in a proposed Multiple Use Area in this region from 1987 through 1991, FIIT researchers collected or observed 254 avian species, of which 44 are regarded as Nearctic migrants and 26 are known or suspected to have both resident and long-distance migrant populations. Study sites included climax and selectively logged lower montane forest fragments, as well as subtropical agroecosystems. Data are presented to support the conclusion that a significantly higher percentage of resident avian species reported from this region in the literature continue to occupy these habitats than do species known to undertake cyclical longdistance migrations. Non-quantitative, historical reports of relative abundance of all Nearctic avian migrants in the region during the early and mid-twentieth century are compared with current status of these species. Threats to Nearctic avian migrants in the western Guatemalan highlands are discussed, and areas of future research for ornithologists working with this community in the region are proposed. Recommendations are made to preserve or improve habitats on wintering grounds and along migration routes considered to be of critical importance for the long-term survival of a number of threatened and vulnerable Nearctic avian migrants in Guatemala.
Factors affecting migratory bird routes over the Gulf of Mexico
Authors: Rappole John H. , Ramos Mario A. 
Published: May 2010

SummaryOver half of the 332 migratory bird species that breed in North America and winter in the tropics are affected by the obstacle to migratory flight presented by the Gulf of Mexico. Landbird migration in the vicinity of the Gulf is considered from an historical perspective, and in light of netting and observational data from the western Gulf coast. A trans-Gulf crossing from the northern Gulf coast to, or over, Yucatan is the most commonly followed fall route for eastern Nearctic migrants that winter in Central America. The spring route for these species is different, involving a more westerly trans–Gulf course for some individuals, and a circum–Gulf route for others. Prevailing wind direction and the probability of meeting turbulence over the Gulf are suggested as the main selective factors affecting route form for Gulf–area migrants.