ORNITHOLOGICAL SCIENCE
Print ISSN : 1347-0558
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ORIGINAL ARTICLE
  • Magne HUSBY
    Volume 16 (2017) Issue 2 Pages 111-119
    Released: August 08, 2017
    JOURNALS RESTRICTED ACCESS
    Information about the relative frequency and geographical variation of colour aberrations in birds is rare. By entering the word Magpie Pica pica in 37 European languages into an Internet search engine, I was able to trace 3,974 photographs in 2015 and 3,672 photographs in 2016 in more than 40 countries. By analysing the photographs, I found a significant difference in the frequency of aberrant Magpies, with the frequency increasing northwards and decreasing eastwards. Leucism was the most common aberration, followed by brown (brown and ino) and dilute. Despite some changes in the number of Magpie pictures found for each language between the two years, the numbers correlated strongly. The percentage of aberrant Magpies found for each language in 2015 correlated significantly with the percentage in 2016. While using pictures obtained from the Internet has inherent biases and limitations, it is also a useful new tool revealing patterns in geographical variation in aberrant colouration in several bird species, and allowing us, eventually, to understand the differences.
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  • Erick Nickson OTIENO, Laurent FRENETTE
    Volume 16 (2017) Issue 2 Pages 121-129
    Released: August 08, 2017
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    The Eastern Wild Turkey Meleagris gallopavo silvestris has long been regarded as a corn pest, but with little tangible evidence although it is occasionally sighted consuming pieces of corn left on the ground, or corn is often found in its crop after slaughter. To test the corn pest paradigm, land cover characterization, turkey dispersal assessment and analyses of δ13C and δ15N isotopes were used to evaluate the relative influence of major land cover features on the species' assemblage and corn consumption rate across an intensively farmed region in south-east Quebec, where croplands are dominated by corn fields. Mean numbers of turkeys encountered were highest in regions with a greater mix of forest, cropland and open space matrices, and particularly higher crop-field cover and proximity to water bodies. However, the contribution of corn in the turkey diet was primarily correlated with forest cover rather than with overall crop-field size, suggesting that corn was not the primary attractant. Areas with extensive road networks also supported high rates of corn consumption, indicating that true corn pests use these to raid cornfields and leave remnants that turkeys then consume. Adult turkeys predominantly consume plant food sources, particularly C3 plants, while juveniles mostly consume invertebrates, several of which constitute crop pests. Conclusively, corn constituted only an opportunistic and supplementary component of turkey diet, especially where cornfields neighboured forests. Furthermore, turkey foraging flocks may in fact collectively serve as significant suppressors of crop pests across agricultural landscapes, rather than being corn depredators.
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  • Bhoj Kumar ACHARYA, Lalitha VIJAYAN
    Volume 16 (2017) Issue 2 Pages 131-140
    Released: August 08, 2017
    JOURNALS FREE ACCESS
    We examined the vertical stratification of birds in relation to foliage in different vegetation types along an elevation gradient in Sikkim, Eastern Himalaya, India. We used variable-width point count methods for sampling birds spread across 20 transects along an elevation gradient from 300 m to 3,800 m above mean sea level. We estimated species richness, abundance and Shannon-Weiner diversity (H′) of birds in seven height categories (0 m, 0-5 m, 5-10 m, 10-15 m, 15-20 m, 20-25 m and >25 m). Foliage structure and complexity of vegetation was assessed along all transects following Erdelen (1984) and Jayson and Mathew (2003). Birds displayed distinct vertical stratification in terms of species richness, abundance and diversity in Sikkim. Overall, maximum species richness (231) was observed at 0-5 m height followed by 5-10 m, 10-15 m and the ground layer (0 m). There was no significant difference in stratification pattern among elevation zones. Each height class harboured distinct species composition of birds with low similarity among height categories. We observed maximum foliage concentration within 10 m height from the ground, and the trend was consistent in all of the zones. Correlation analysis revealed significant positive relations between foliage abundance and species richness, abundance and diversity of birds. Results of this study have highlighted the significance of under-storey or sub-canopy vegetation in maintaining and conserving avifaunal diversity in the Eastern Himalaya.
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  • Navjeevan DADWAL, Dinesh BHATT
    Volume 16 (2017) Issue 2 Pages 141-146
    Released: August 08, 2017
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    Discrimination between neighbours and strangers, on the basis of acoustic cues, has been clearly demonstrated in many temperate avian species, but experiments on neighbour-stranger recognition have received less attention in tropical habitats, particularly in the Indian subcontinent. With this in mind, neighbour-stranger discrimination experiments were conducted on tropical male Pied Bushchats Saxicola caprata in the District Haridwar, of the Himalayan foothills, India. The sound levels of broadcasted songs were kept as close as possible to natural song levels. The results of the parameters analysed (including song rate, song repertoire, flights toward the speaker, distance from the speaker, and latency) did not differ significantly between neighbour and stranger song playbacks. It seems that male Pied Bushchats responded evenly toward the playback and may be incapable of discriminating between neighbours and strangers.
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  • Idriss BOUAM, Abdelkrim SI BACHIR, Naoki KATAYAMA
    Volume 16 (2017) Issue 2 Pages 147-157
    Released: August 08, 2017
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    Despite the fact that the Mediterranean basin is considered to be a global biodiversity hotspot for flora and fauna, studies investigating the benefits of agri-environmental schemes on biodiversity conservation in perennial agro-ecosystems in this region are scarce, particularly for bird communities in North Africa. This study investigated the effect of agricultural intensification on bird assemblages in olive orchards in north-eastern Algeria. Bird counts were conducted along an agricultural intensification gradient during twelve consecutive months (from March 2014 to February 2015). Accumulation curves and non-parametric estimators for incidence-based data were used to estimate the total species richness of birds. GLMMs, PERMANOVA and non-metric multidimensional scaling analyses were conducted to evaluate and to visualize the variation in species composition among the studied sites during the breeding and non-breeding seasons. Overall, the total species richness of birds decreased with the increasing level of agricultural intensification. Additionally, among the three trophic guilds (insectivore, granivore and omnivore), the frequency of occurrence of insectivorous and granivorous birds tended to decrease with increasing agricultural intensification. We explored possible reasons for the observed patterns, in relation to differences in the intensity of agricultural management, between the olive orchards studied. This study provides the first qualitative data, which suggests that less intensive agriculture can enhance avian diversity, particularly of insectivorous and granivorous birds, in olive orchards in Algeria.
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SHORT COMMUNICATION
  • Tetsuo SHIMADA, Naoya HIJIKATA, Ken-ichi TOKITA, Kiyoshi UCHIDA, Masay ...
    Volume 16 (2017) Issue 2 Pages 159-162
    Released: August 08, 2017
    JOURNALS RESTRICTED ACCESS
    The spring migration routes of the Brent Goose Branta bernicla nigricans wintering in Japan can extend beyond those of earlier-published trajectories from satellite data (Shimada et al. 2016). This conclusion is based on a ring recovered from a goose shot by a hunter, found south of the Lena Delta in the Russian high arctic. Building on the previously published satellite-tracking data from the same population, we suggest that the geese migrate northward in Russia following an interior route along the Lena and Yana rivers after arriving at the northern coast of the Sea of Okhotsk from Japan during spring migration.
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