山西平陆越冬大天鹅日间行为模式

2011年12月至2012年2月和2012年11月至2013年1月,采用瞬时扫描法,对山西平陆黄河湿地越冬的大天鹅进行了日间行为时间分配和活动节律的研究。结果表明,大天鹅在越冬期的主要行为是静息、运动和取食,分别占全部行为比例的(40.5±1.4)%、(22.8±0.9)%和(18.2±0.8)%。在日间节律方面,大天鹅的取食行为呈现早晚双高峰,静息行为的高峰则出现在早上和中午。对不同地点的大天鹅的行为时间分配研究表明,大天鹅在两地的行为时间分配存在明显差异。其中,在干扰强度较大的三湾村,运动和争斗行为更多;在干扰较小的关家窝村,静息和警戒行为更多。在行为时间分配与温度变化关系的研究中,通过Pearson相关性分析发现,大天鹅的取食、运动和理羽行为与温度成显著正相关,静息和警戒行为与温度呈现显著负相关。     

Vergleich von Habitatstruktur und Habitatnutzung in Brutgebiet und Winterareal des Europ?ischen Pirols (Oriolus o. oriolus, L. 1758)

Zusammenfassung Im Brutgebiet des Pirols in Schleswig-Holstein sowie im Winterareal in Simbabwe wurden auf individuenbezogenen Untersuchungsflächen (bird-use-plots, Capen et al. 1986) Vegetationsstruktur und Habitatnutzung erfaßt und verglichen. Der Lebensraum in Afrika ist offener als im Brutgebiet (durchschnittlich 573 Bäume/ha in Afrika gegenüber 865 Bäumen/ha im Brutgebiet) und die Baumbestände sind niedriger (durchschnittliche maximale Vegetationshöhe in Afrika 14 m gegenüber 16,2 m im Brutgebiet). Auch die vertikale Laubverteilung der Bestände ist unterschiedlich. Gemeinsam ist den Habitaten ihre Saisonalität und ihr Strukturreichtum. Vergleicht man als Maße für den Strukturreichtum den Diversitätsindex der vertikalen Laubverteilung und die Heterogenitätsindices für Kronendeckung und Baumdichte, so liegen im Brutgebiet die Diversitätsmaße der vertikalen Laubverteilung um 21 % höher als in Afrika, während dort die Heterogenität der Baumverteilung um 25% und die der Kronendeckung um 29% höher sind. In beiden Gebieten werden vom Europäischen Pirol häufig solche Gehölze aufgesucht, deren floristische Zusammensetzung von wenigen Baumarten dominiert wird.Bei der Nahrungssuche sind die Europäischen Pirole im Brut- wie im Überwinterungsgebiet im Außenbereich der Krone in etwa 85 % der Baumhöhe und oberhalb der Zone mit der maximalen Laubdichte zu finden. Sie bevorzugten in beiden Gebieten Bäume von etwa 13–14 m Höhe.

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Habitat structure and habitat use of European Golden Orioles (Oriolus o. oriolus, L. 1758) during breeding and wintering

Summary Habitat structure and habitat use of European Golden Orioles were compared in breeding and wintering habitats of northwestern Germany and Zimbabwe. In 25 bird use plots per area, tree density, crown cover, vertical foliage distribution, maximal vegetation height and stratum of maximal vegetation density were measured as an analysis of vegetation structure. For habitat use, the height of trees used by the birds, the horizontal and vertical position of birds in the trees and behavioural parameters were observed.Woodlands in Zimbabwe are lower (14,2 vs 16 m maximal height of vegetation) and more open (573 trees/ha vs 865 trees/ha) than breeding habitats in Schleswig-Holstein and show differences in vertical vegetation structure. Both habitats show well developped vegetation structure and seasonality. In northwestern Germany the diversity of vertical foliage distribution is about 21 % higher than in the plots of Zimbabwe, however in Africa the heterogeneity of tree distribution is 25 % higher and the index of heterogeneity of crown cover is 29 % above the data measured in the breeding habitats. The floral composition in both habitats is dominated by a few tree species.In respect to habitat use no niche shift could be documented between breeding and wintering areas as the birds prefer the outer crown area of trees of 13 – 14 m in height. European Golden Orioles can normally be found at about 85 % of tree height, closely above the zone of maximum vegetation density.

     

Hope for the White-headed Duck,Oxyura leucocephala (Aves: Anatidae) in Turkey despite a declining breeding population and abandonment of its traditional wintering area?

The development of the breeding and non-breeding populations of the White-headed Duck, Oxyura leucocephala, in Turkey was analysed based on all available records from the period 1966–2016 from 99 different areas. Breeding is confined to Inner Anatolia and the eastern parts of the country. The breeding population had been estimated as 200–250 pairs in the period 1996–2001 but recent observations show that it does now not exceed 80–125 pairs which is a decline of about 50% within two decades. The non-breeding winter population comprises approximately 8,500–10,000 individuals. Burdur Lake has traditionally housed more than 90% of the population but is no longer a significant resting place. The numbers started to decrease from more than 10,000 birds at the beginning of the 1990s to a few hundred in the early 2000s. Now only very small numbers overwinter there. The reason seems to be a combination of water pollution and decreasing water level. After a period of more than 10 years, the numbers in Turkey started to increase again, and most birds are now concentrated at Manyas Lake in Western Anatolia. In 2016, the population reached a winter maximum of approximately 6,000. In the post-breeding season, up to 4,000 individuals were recorded in Eastern Anatolia in October 2014 which is far more than has ever been recorded in this season before.     

Winter Avian Community and Sparrow Response to Field Border Width

Abstract: Transformations of agricultural practices in the southeastern United States have drastically reduced preexisting quantities of strip-cover habitat along field margins. The National Conservation Buffer Initiative has promoted the establishment of herbaceous field borders to restore wildlife benefits once provided by such habitat. We evaluated effects of native warm-season grass field border establishment and width on winter bird response. Narrow (approx. 8-m) field borders represented a marginal improvement to non-bordered margins that were cropped ditch to ditch, whereas wide (approx. 30-m) borders significantly enhanced total avian conservation value, abundance, species richness, and sparrow abundance compared to non- or narrow borders. Furthermore, presence of wide borders altered bird use of row-crop fields. We observed increased sparrow (Emberizidae) abundances in agricultural fields adjacent to wide borders, which likely resulted from enhanced waste grain foraging opportunities. Given these benefits to wintering farmland birds, we advocate the integration of herbaceous field border habitat in agricultural landscapes, particularly borders of enhanced width.     

Population Structure of Tundra Swans Wintering in Eastern North America

ABSTRACT Our objective was to determine whether there were subpopulations within the eastern population of tundra swans (Cygnus columbianus columbianus) wintering along the mid-Atlantic coast. Movement rates between regions were substantial enough to result in continual mixing of wintering birds. Thus, we were unable to identify distinct subpopulations based on exclusive use of specific wintering areas. These birds should therefore be monitored, and their harvest managed, as if they were one population.     

Spatial and temporal patterns in age structure of Golden Eagles wintering in eastern North America

The behavior of wildlife varies seasonally, and that variation can have substantial demographic consequences. This is especially true for long-distance migrants where the use of landscapes varies by season and, sometimes, age cohort. We tested the hypothesis that distributional patterns of Golden Eagles (Aquila chrysaetos) wintering in eastern North America are age-structured (i.e., birds of similar ages winter together) through the analysis of 370,307 images collected by motion-sensitive trail cameras set over bait during the winters of 2012–2013 and 2013–2014. At nine sites with sufficient data for analysis, we documented 145 eagle visits in 2012–2013 and 146 in 2013–2014. We found significant between-year variation in age structure of wintering eastern Golden Eagles, driven largely by annual differences in the proportion of first-winter birds. However, although many other species show spatial structure in wintering behavior, our analysis revealed no latitudinal organization among age cohorts of wintering eastern Golden Eagles. The lack of age-related latitudinal segregation in wintering behavior does not exclude the possibility that these eagles have sex-based or other types of dominance hierarchies that could result in spatial or temporal segregation. Alternatively, other mechanisms such as food availability or habitat structure may determine the distribution and abundance of Golden Eagles in winter.     

Habitat characteristics of wintering Wood Warbler Phylloscopus sibilatrix in the Centre Region of Cameroon: conservation implications

Populations of many Afro-Palearctic birds have declined, with those wintering in sub-Saharan Africa, such as Wood Warbler Phylloscopus sibilatrix, particularly affected. In this study we investigated the relationship between habitat characteristics and Wood Warbler presence/absence in the Centre Region of Cameroon. A total of six transects were established in three habitat types (forest, forest–savanna transitional zone and savanna). Call playback surveys were conducted monthly from November 2015 to April 2016 to determine Wood Warbler presence/absence. Detailed habitat measurements were also recorded in each transect. A total of 86 responses were recorded: 33 (mean 6.6 ± 2.3) in forest habitat, 47 (mean 9.4 ± 3.36) in the forest–savanna transitional zone, and 6 (mean 2 ± 1.1) in savanna habitat. Wood Warbler presence increased significantly with the number of trees between 3 and 7 m in height, and decreased significantly with the number of shrubs between 0.5 and 3 m in height. Anthropogenic disturbance such as the agricultural cycle and burning were not found to have an effect on Wood Warblers presence/absence. We conclude that Wood Warblers overwinter in all three habitat types with probability of detection greatest in the forest–savanna transitional habitat with a relatively low canopy and an open understorey. Forest clearance in sub-Saharan Africa potentially threatens wintering habitat for Wood Warblers.