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Thursday, 29 October 2015

Bird Conservation International, Volume 25, Issue 04, December 2015: Abstracts



VOLUME 25 - ISSUE 04  - December 2015
Breeding ecology and predictors of nest success in the Critically Endangered Ridgway’s Hawk Buteo ridgwayi
Department of Biology, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.
Wildlife Preservation Canada, RR#5 5420 Highway 6 North, Guelph, Ontario, N1H 6J2, Canada.

Ridgway’s Hawk Buteo ridgwayi is a Critically Endangered forest raptor endemic to the island of Hispaniola in the Caribbean. The species is currently limited to a small area on the north-east coast of the island, with fewer than 110 pairs remaining. From 2005 to 2009 we studied its breeding ecology, finding that Ridgway’s Hawks have a clutch size (2.0 ± 0.4 eggs) similar to other tropical raptors and island Buteo species. Fledging rate of 0.64 fledglings per active nest (fledgling nest-1) with pairs raising a single brood per year was also similar to that of other tropical Buteo species. Nest success was 40% (n = 151), with the majority of nest failures caused by human disturbance. The two significant predictors of nest success and fledging rate were related to human persecution: nest height and territory disturbance index. Pairs were able to tolerate human activity in their territory if there was no direct disturbance to the immediate nest area. Conservation planning for Ridgway’s Hawk must focus on community awareness programmes targeting local user groups within Los Haitises National Park regarding the uniqueness and endangered status of the hawk, and effective protection of the remaining karst forest in Los Haitises.
Vulture populations in Uganda: using road survey data to measure both densities and encounter rates within protected and unprotected areas
Department of Biological Sciences, Makerere University, PO Box 7298 Kampala, Uganda.
School of Biology, Harold Mitchell Building, University of St Andrews, Fife, KY16 9TH, UK.
Institute of Tropical Forest Conservation, Mbarara University of Science and Technology, PO Box 44, Kabale, Uganda.
NatureUganda, PO Box 27034 Kampala, Uganda.
Uganda Wildlife Authority, PO Box 3530 Kampala, Uganda.
The Peregrine Fund, 5668 West Flying Hawk Lane, Boise, Idaho 83709, USA.
National Museums of Kenya, Ornithology Section, Box 40658, 00100 Nairobi, Kenya.

Six out of seven vulture species whose global ranges lie largely or wholly within Africa are listed as globally threatened. Since their current distributions individually span up to 39 range states there is a pressing need to develop robust, standardised methods that provide a clear measure of range-wide changes in abundance. Yet, survey methods currently used tend to yield either of two measures: estimates of breeding density, derived mainly from nest counts; or linear encounter rates, derived from road surveys. Here, we present the results of a six-year survey of six vulture species in Uganda, in which we used road counts, in combination with Distance sampling, to determine both encounter rates and densities within protected areas (PAs), and in predominantly pastoral and agricultural areas. In combination, five scavenging species were detected 4–6 times more frequently in PAs than elsewhere, and two species, White-backed Vulture Gyps africanus and Lappet-faced Vulture Torgus tracheliotus, were recorded only within PAs. We estimate that PAs held c.1,300–3,900 individuals of the five scavenging species combined, including c.1,250–2,900 individuals of two Gyps species. We also present national population estimates for two species: White-backed Vulture (c.1,000–2,600 birds) and Lappet-faced Vulture (c.160–500 birds). Although sightings were assigned to only three broad distance bands, Distance sampling provided estimates with a level of precision similar to that achieved for linear encounter rates, but as density estimates; a form more readily comparable with results obtained from other survey types.
Population and spatial breeding dynamics of a Critically Endangered Oriental White-backed Vulture Gyps bengalensis colony in Sindh Province, Pakistan
Hawk Conservancy Trust, Andover, Hampshire SP11 8DY, UK; and Centre for Wildlife Assessment and Conservation, School of Biological Sciences, University of Reading, Reading, Berkshire RG5 6AS, UK.
WWF-Pakistan, Ferozepur Road, Lahore, 54600, Pakistan.

The Critically Endangered Oriental White-backed Vulture Gyps bengalensis has declined across most of its range by over 95% since the mid-1990s. The primary cause of the decline and an ongoing threat is the ingestion by vultures of livestock carcasses containing residues of non-steroidal anti-inflammatory drugs, principally diclofenac. Recent surveys in Pakistan during 2010 and 2011 revealed very few vultures or nests, particularly of White-backed Vultures. From 2011 in the Tharparkar District of Sindh Province we monitored a colony of Oriental White-backed Vultures. Between 2011 and 2014 the number of active nests in this colony increased from 11 to 34 while nest density decreased from 13.7 to 9.2 nests km-2, suggesting that the colony is expanding. We conclude that the rate of increase is being subsidised by immigration, as the population demographics do not support the observed rate of increase in nests. We present the first analysis of spatial breeding dynamics for the Oriental White-backed Vulture and describe how a clustered pattern of nest trees in colonies supports a highly clustered pattern of nests. The spatial pattern of nests relies on both the distribution of trees and the ability of trees to support more than one nest. These results highlight that the preservation of larger nest trees and the sustainable management of timber resources are essential components for the conservation management of this species. We emphasise the high importance of this colony and a nearby Long-billed Vulture Gyps indicus colony in this area of Pakistan. Recommended conservation management actions include the continuation of a Vulture Safe Zone established in 2012, measuring breeding success, assessing dispersal and determining the impact of mortality on these populations.

Identifying key demographic parameters for the viability of a growing population of the endangered Egyptian Vulture Neophron percnopterus
Conservation Biology Group, Departament de Biologia Animal, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Catalonia, Spain.
C. Barcelona, 29. 08600 Berga. Catalonia. Spain.
Grup de Naturalistes d’Osona, C. de la Laura, 13. 08500 Vic, Catalonia, Spain.
C. Ramón Turró, 5, Esc A, 4t-3a, 08005- Barcelona. Catalonia, Spain.

The Egyptian Vulture Neophron percnopterus is a threatened species throughout its worldwide range. The Iberian Peninsula holds 50% of its global population, which has declined by 25% over the last 20 years. Despite this negative global trend, an increase in the number of individuals over the last 25 years has been observed in Catalonia, where it has colonised areas in which it was previously unknown. In this study, we describe the demographic evolution of an increasing population of Egyptian Vultures in central and eastern Catalonia and we apply population models and maximum likelihood procedures to investigate both the main demographic processes driving the observed trends and the viability of the population. The number of pairs in this region increased from one to 22 in the period 1988–2012. The best-supported models suggest that adult survival in this population may be higher than in other Iberian populations and that furthermore, there is a continuous influx of immigrants. Based on the most likely scenarios, Population Viability Analysis predicts that the population will continue to increase. Sensitivity analysis indicates that the adult survival rate has the greatest influence on population dynamics so conservation efforts will be more effective if concentrated on improving this rate.

Population decline and range contraction of the Egyptian Vulture Neophron percnopterus in the Balkan Peninsula
Macedonian Ecological Society, PO Box 162, 1000 Skopje, the FYR of Macedonia.
Bulgarian Society for Protection of Birds / BirdLife Bulgaria, Yavorov complex, bl. 71, vh. 4, PO box 50, 1111 Sofia, Bulgaria.
Institute for Nature Conservation of Serbia, Voždova 14, 18000 Niš, Serbia.
RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, UK.
Laboratory of Ecology, Department of Biological Applications and Technology, University of Ioannina, University Campus, 45110, Ioannina, Greece, and Hellenic Ornithological Society, Themistokleous 80, GR-10681 Athens, Greece.
WWF Greece, 21 Lambessi, Gr 117 43 Athens, Greece.
Forestry Service of Ioannina, M. Kotopouli 62, Ioannina, 45445 Greece.
40008 Rapsani, Greece.
Hellenic Ornithological Society, Themistokleous 80, GR-10681 Athens, Greece.          
Eressou 35, GR- 10681 Athens, Greece.         
Management Authority of Kalamas and Acherontas Gorges and Deltas, Eirinis kai Filias 1, GR-46100 Igoumenitsa, Greece.
Nature Conservation Association “Aquila”, Belasica 3, 1400 Kavadarci, the FYR of Macedonia.
Protection and Preservation of Natural Environment in Albania, Rr. Vangjush Furrxhi, Pall 16, Shk 1, Ap 10, 1000 Tirana , Albania.

The Egyptian Vulture has been classified as ‘Endangered’ due to a rapid population decline in India and long term declines in Europe and Africa. Although the species has been reported to be declining in Eastern Europe, no quantitative assessment of the magnitude or the causes for population declines are available. We used monitoring data from the Balkan Peninsula to estimate changes in population size and extent of occurrence of Egyptian Vultures between 1980 and 2013. We quantified population trends in three countries (Bulgaria, Greece and the former Yugoslav Republic [FYR] of Macedonia) to assess whether population declines are similar within the Balkan range states. We found a rapid and consistent decline of the Egyptian Vulture population that was largely similar among the three countries (λ = 0.940 in FYR of Macedonia, 0.951 in Bulgaria, 0.920 in Greece). As a consequence of population declines, the breeding range of Egyptian Vultures has contracted and the population in the Balkan Peninsula has fragmented into six subpopulations separated by more than 80 km. Population declines may be driven by factors such as poisoning, electrocution, direct persecution and changes in food availability which operate at large spatial scales and affect birds both on breeding grounds as well as during migration and wintering. Because the relative importance of threats to the survival of Egyptian Vultures are poorly understood, there is a critical need for research into causes of mortality and potential conservation actions that may halt and reverse population declines.

An assessment of the distribution, population size and conservation status of the Santa Marta Foliage-gleaner Automolus rufipectus: a Sierra Nevada de Santa Marta endemic
SELVA: Investigación para la Conservación en el Neotrópico, Bogotá, Colombia.
Instituto de Ecología y Biodiversidad, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Laboratorio de Biología Evolutiva de Vertebrados, Universidad de los Andes, Bogotá, Colombia.

The Santa Marta Foliage-gleaner Automolus rufipectus is one of 19 endemic bird species found in the Sierra Nevada de Santa Marta (SNSM) in northern Colombia but until recently it was considered a sub-species of the Ruddy Foliage-gleaner Automolus rubiginosus. Consequently, published information on its distribution and ecology is lacking, and while it is classified as near- threatened, this designation was based on limited quantitative data. To improve our knowledge of the Santa Marta Foliage-gleaner’s geographical distribution, elevation range, population density, habitat use and conservation status, we analysed both historical and recent site locality records and carried out variable distance transects within forested habitats and shade coffee plantations. We modelled the environmental niche of the species and subsequently estimated its extent of occurrence and area of occupancy, as well as population size. Our results consistently showed that the distribution of the Santa Marta Foliage-gleaner is more restricted than previously considered, both geographically and by elevation (we redefine elevation range as 600–1,875 m). This suggests that the species is more at risk of habitat transformation and combined with our estimates of population size (< 10,000 individuals), it is likely that the species will be uplisted to a higher threat category. More positively, and contrary to published accounts, we found that approximately 40% of the species’ range lies within protected areas. Nevertheless, we recommend the implementation of strategies to maintain forest cover on the western flank of the SNSM and further research to better define the species’ habitat needs and population dynamics.

Mapping the potential distribution of the Critically Endangered Himalayan Quail Ophrysia superciliosa using proxy species and species distribution modelling
School of Biology, Newcastle University, Newcastle-upon-Tyne, Tyne and Wear, NE1 7RU, UK.
RSPB Centre for Conservation Science, RSPB, The Lodge, Sandy, Bedfordshire, SG19 2DL, UK.
and Wildlife Conservation Society, PO Box 277, Goroka, Eastern Highlands Province, Papua New Guinea.

The Critically Endangered Himalayan Quail Ophrysia superciliosa has not been reliably recorded since 1876. Recent searches of historical sites have failed to detect the species, but we estimate an extinction year of 2023 giving us reason to believe that the species may still be extant. Species distribution models can act as a guide for survey efforts, but the current land cover in the historical specimen record locations is unlikely to reflect Himalayan Quail habitat preferences due to extensive modifications. Thus, we investigate the use of two proxy species: Cheer Pheasant Catreus wallechi and Himalayan Monal Lophophorus impejanus that taken together are thought to have macro-habitat requirements that encapsulate those of the Himalayan Quail. After modelling climate and topography space for the Himalayan Quail and these proxy species we find the models for the proxy species have moderate overlap with that of the Himalayan Quail. Models improved with the incorporation of land cover data and when these were overlaid with the Himalayan Quail climate model, we were able to identify suitable areas to target surveys. Using a measure of search effort from recent observations of other galliformes, we identify 923 km2 of suitable habitat surrounding Mussoorie in Northern India that requires further surveys. We conclude with a list of five priority survey sites as a starting point.

Multi-scale habitat use analysis and interspecific Ecology of the Critically Endangered Black-breasted Puffleg Eriocnemis nigrivestis
Área de Investigación y Monitoreo de Avifauna, Aves y Conservación – BirdLife in Ecuador. Pasaje Joaquín Tinajero E3-05 y Jorge Drom. Casilla 17-17-906, Quito, Ecuador and Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Science Park, 1098 HX, Amsterdam, The Netherlands.
Centro de Investigación en Biodiversidad y Cambio Climático, Universidad Tecnológica Indoamérica, Machala y Sabanilla, Quito, Ecuador.
Institute for Biodiversity and Ecosystem Dynamics, Universiteit van Amsterdam, Science Park, 1098 HX, Amsterdam, The Netherlands.

AbstractThe Black-breasted Puffleg Eriocnemis nigrivestis is a hummingbird endemic to Ecuador and considered Critically Endangered, given its limited distribution, low population numbers, and ongoing habitat degradation. We investigated habitat use patterns using landscape and microhabitat variables. In addition, we explored a previously postulated competition hypothesis involving the Black-breasted Puffleg and the Gorgeted Sunangel Heliangelus strophianus. Our results suggest that landscape variables may play a role in the habitat selection process; specifically the distance to nearest forest border seems to have a significant effect on our habitat model. We speculate that, as the species is known to perform seasonal movements, the avoidance of forest border might reduce the physiological stress caused by altitudinal migration. At microhabitat level, Black-breasted Puffleg seems not sensitive to forest structure variables. Our findings suggest that ensuring forest tract connectivity, between the altitudinal extremes of the species’ range at the north-western flanks of the Pichincha volcano, might be crucial for survival of the species during its annual cycle. However, non-metric multidimensional scaling (NMDS) indicates that Black-breasted Puffleg and the Gorgeted Sunangel do not overlap spatially, but this finding is not conclusive considering our field observations.


The geographic and seasonal potential distribution of the little known Fuertes’s Oriole Icterus fuertesi
Red de Biología Evolutiva, Instituto de Ecología, A. C., Km. 2.5 carretera antigua a Coatepec 351, El Haya, Xalapa, Veracruz, 91070, México.

AbstractEndemic species and those with restricted distribution ranges are a priority and national responsibility for global conservation. Fuertes’s Oriole Icterus fuertesi is a Mexican endemic species and is perhaps one of the least known birds in the country. It has traditionally been regarded as conspecific with the Orchard Oriole I. spurius, but recently it has been suggested that it is a distinct species, causing concern about its risk status. There is a scarcity of information related to the geographic and seasonal distribution of Fuertes’s Oriole, as well as a lack of information regarding its abundance and habitat preferences. We gathered all the available records, and used ecological niche modelling to analyse the spatial and temporal patterns of the distribution of the species. We also carried out field surveys in the surroundings of known locations of the species in order to determine its abundance. We found that the species is narrowly and locally restricted to the surroundings of eight localities along the Gulf coast of Mexico that constitute small and discontinuous areas of presence. We also found no evidence of migration to the Pacific Coast in winter, as has been historically thought. Instead, our results suggest that the species exhibits a short-distance migration, with northern populations migrating to the southern range along the Gulf coast of Mexico. Analysis of abundance and field observations confirm that the species is restricted to highly modified wetland landscapes associated with urban and semi-urban habitats. Based on these results, we suggest the urgent reassignment of its risk category.

The Forest Thrush Turdus lherminieri prefers mature mesic forest with dense canopy
School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 1QX, UK.
Montserrat Department of Environment, PO Box 272, Brades, Montserrat, West Indies.
BirdLife International, Wellbrook Court, Girton Road, Cambridge, CB3 0NA, UK.

Habitat loss, the primary driver for loss of biodiversity worldwide, is of special concern for species that have a small area of occurrence, such as those restricted to islands. The Forest Thrush Turdus lherminieri is a ‘Vulnerable’ (VU) species endemic to four islands in the Caribbean, and its population has declined dramatically over the past 15 years. Because this decline is poorly understood, we studied its habitat associations on Montserrat. We conducted three repeat point count surveys and measured forest structure and habitat at each of 88 randomly placed locations in the largest forest area remaining on the island. We related Forest Thrush abundance to habitat using binomial mixture models that account for imperfect detection. Detection probability was a function of survey time, survey date, location of the survey point, and wind. Local habitat structure had the greatest influence on Forest Thrush abundance, with birds being more abundant at mid-elevations under closed canopies. We conclude that the Forest Thrush prefers mature mesic and wet forests on Montserrat. Assuming similar habitat selection in the rest of its range, the species’s long-term future depends on good protection of these natural forests on all four islands where it occurs.


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