乌鲁木齐市区越冬期长耳鸮的食性分析

2009～2011年间,利用食团分析法对乌鲁木齐市越冬长耳鸮(Asio otus)的食性进行分析。3年累计收集长耳鸮食团683份,辨认出1 132只猎物。分析结果表明,长耳鸮在冬季共捕食小型哺乳类6种,鸟类2种。小家鼠(Mus musculus)是最常见的食物,占总捕食量的53.45%。小型哺乳类是长耳鸮的主要食物,它在食物组成中出现的总频率为88.16%,以生物量计,小型哺乳类占食物构成的95.13%。长耳鸮的食物组成年度间差异显著,与当地猎物资源多样性和可获得性密切相关,表明长耳鸮可能采用机会主义者的捕食策略。     

长耳Hao在越冬期的习性,数量及食性

长耳Ｈａｏ在保定市的越冬期为１８０天左右。１０月到１１月份数量逐渐增多,１２月到翌年２月份数量趋于稳定,达２４０只以上;３、４月份数量逐渐减少,通过对１０２８块食物残块的分析得出其９１．１％的食物为鼠类,月变动范围在８５．５％到９８．５％。     

长耳鸮越冬栖息地环境因子分析

通过对河北省保定市直隶总督署博物馆越冬长耳鸮种群数量和习性的长期观察及其越冬栖息地环境因子的分析,得出如下结论:总督署博物馆虽地处保定闹市中心,但由于其建筑格局等因素影响,院内噪声值、大气中的二氧化硫、氮氧化物、总悬浮物微粒的含量明显低于院外;博物馆院内种植有多株高大的常绿乔木,为长耳鸮提供了良好的栖息、隐蔽场所;越冬长耳鸮种群数量的变动与温度有一定的对应关系;近年来在总督署博物馆大院内越冬栖息的长耳鸮数量有较大波动,且有下降趋势,这与总督署博物馆的改建、游客数量增多、食物短缺及冬季气温升高等因素有关.     

长耳鹗在越冬期的习性、数量及食性

长耳在保定市的越冬期为１８０天左右。１０月到１１月份数量逐渐增多；１２月到翌年２月份数量趋于稳定，达２４０只以上；３、４月份数量逐渐减少。通过对１０２８块食物残块的分析得出其９１．０％的食物为鼠类，月变动范围在８５．５％到９８．５％。     

长耳鴞越冬栖息地环境因子分析

通过对河北省保定市直隶总督署博物馆越冬长耳种群数量和习性的长期观察及其越冬栖息地环境因子的分析 ,得出如下结论 :总督署博物馆虽地处保定闹市中心 ,但由于其建筑格局等因素影响 ,院内噪声值、大气中的二氧化硫、氮氧化物、总悬浮物微粒的含量明显低于院外 ;博物馆院内种植有多株高大的常绿乔木 ,为长耳提供了良好的栖息、隐蔽场所 ;越冬长耳种群数量的变动与温度有一定的对应关系 ;近年来在总督署博物馆大院内越冬栖息的长耳数量有较大波动 ,且有下降趋势 ,这与总督署博物馆的改建、游客数量增多、食物短缺及冬季气温升高等因素有关     

不同栖居地和越冬时期长耳鸮的食物组成

通过分析2003—2006年连续3个冬季北京城区和城郊越冬长耳鸮的食团,研究了长耳鸮食物组成的时间与空间变化特征。每月收集1次长耳鸮食团,通过其内容物分析长耳鸮食物中的猎物种类和数量构成。结果表明：城区和城郊两地长耳鸮3种主要猎物中蝙蝠的被捕食率分别为41.6%和43.0%,鼠类为27.5%和39.4%,鸟类为30.7%和18.9%;城区和城郊长耳鸮的食物构成在2004—2005年与2005—2006年的冬季存在显著差异,初冬和冬末的食物构成差异也呈显著水平;同区域的长耳鸮食物构成在年度间和不同越冬时期皆存在显著差异;两地越冬长耳鸮捕食猎物比例的差异与生存环境中猎物资源的可获得性有关。     

南充高坪机场短耳鸮越冬期的食性分析和习性观察

2006年3～5月,收集南充高坪机场草地和周围松林越冬期短耳鸮(Asio flammeus)的食团,进行食性分析。在805个完整食团和一些零碎的食团中,小型兽类是短耳食物组成的主要成分,占98.4%,其中四川短尾(Anourosorex squamipes)所占比例最高,为97.2%。通过调查短耳鸮的食团在南充高坪机场草地里的分布情况,分析短耳v在机场草地的栖息地选择,发现短耳鸮并没有选择草高和密集的区域作为栖息场所,而高20cm左右的白茅(Imperata cylindrical)丛是短耳最喜欢栖息的场所。     

Density,diet and productivity of Long-eared Owls Asio otus in the Italian Alps: the importance of Microtus voles

Capsule Relatively large populations, feeding predominantly upon voles, were present at higher elevations.

Aims To determine the density, productivity and diet composition of Long-eared Owls breeding at higher elevations.

Methods Population census and breeding biology were investigated, and dietary analysis performed for 32 Long-eared Owl territories that were occupied over a six-year period (2000–05), in a 155 km² study area located in the Noce Valley of the central-eastern Italian Alps.

Results Territories were mainly situated at the edge of large pine forests, near large patches of grassland and/or open-structured apple orchards, at elevations ranging between 540 and 1210 m. Density varied between 10 and 15 pairs/100 km². Mean intraspecific nest spacing averaged 1727 m and territories were either solitary or clumped in loose aggregations of one to five pairs. Mean laying date was 27 March and the mean number of fledged young was 0.95 and 2.13 per territorial and successful pair, respectively. Adults and nestlings were preyed upon by Eagle Owls Bubo bubo and Common Buzzards Buteo buteo, both of them abundant in the study area. Diet was dominated by Common Voles Microtus arvalis, complemented by Apodemus mice and thrushes. Annual variations in owl density, productivity and diet breadth varied in parallel with the occurrence of Common Voles in the diet, suggesting that the owls responded numerically to the availability of their main prey. This confirms earlier analyses on other European populations, but without the marked three- to four-year cycles observed in such areas.

Conclusion The conservation status of the species in these Alpine habitats seemed currently satisfactory. However, the unregulated use of rodenticides in apple orchards and the loss of open habitats associated with land abandonment may represent long-term threats for the species in these habitats.     

Habitat preferences for Long-eared Owls Asio otus and Little Owls Athene noctua in semi-arid environments at three spatial scales

Capsule There is a relationship between owl numbers and the availability of the agri-forest patchwork.

Aims To model habitat preferences at three different scales of two predators largely neglected within the framework of Environmental Impact Assessment (EIA) studies.

Methods We studied habitat preferences of Long-eared Owls and Little Owls by comparing habitat composition around 28 and 78 occupied territories respectively with 55 non-occupied territories in Alicante (eastern Spain). Generalized linear models were used to examine patterns of habitat preference at three different spatial scales: nest-site, home range and landscape.

Results At the nest-site scale, Long-eared Owls preferred wooded areas with few paved roads while Little Owls preferred arid plantations. Furthermore, the probability of finding an occupied territory increased with the proximity of another occupied territory in the surroundings. The home range scale models mirror the feeding requirements of the owls. Thus, Long-eared Owls occupied areas with high percentages of forest, arid plantations, edges between these two land uses, short distances between nests, with presence of conspecifics and little human disturbance. Little Owls occupied arid plantations with high availability of linear structures and the proximity of villages. At the landscape scale, Long-eared Owls eluded extensive forests, and Little Owls preferred arid plantations.

Conclusions We suggest a hierarchical process of habitat selection for both owls regarding fitting trophic resources at the broadest scales and adequate sites for breeding and roosting at the smallest scale. EIA studies must consider that protecting small areas around single nests may not be an efficient conservation option compared with preserving clusters of territories for both species.     

Population increase of the Long-eared Owl,Asio otus (Linnaeus, 1758), in Iran (Aves: Strigidae)

The Long-eared Owl, Asio otus (Linnaeus, 1758), was known as a scarce wintering bird in Iran until 2010. There were altogether 25 records until the 1970s, but no data are available for the period between the 1970s and 1997. Between 1997 and 2014 there were at least 32 non-breeding and 17 breeding records available based on data of the Iran Bird Records Committee. Breeding was first confirmed in Nahavand (Hamedan Province) and has in the meantime been confirmed at 11 localities mainly in the western half of the country. The recent increase in records (from 25 records during 12 decades compared with 49 records during two decades) indicates that there has been a real increase in the numbers of Long-eared Owls occurring in Iran.     

Diet of a nesting pair of Long-eared Owls,Asio otus,in an urban environment in southwestern Turkey (Aves: Strigidae)

Pellets were collected under an active Long-eared Owl (Asio otus) nest in the city centre of Denizli, Turkey. The nest was located in a conifer tree in a 5.7 ha urban park, centrally-located in the city of Denizli, with a human population of 577,000 people. During April-June 2014, a total of 64 pellets containing remains of 86 individual prey items was found. All prey were Passeriformes and consisted of two species belonging to Passeridae and Hirundinidae. 78 of the 86 prey items (90.7%) were House Sparrow (Passer domesticus) and the other eight (9.3%) were House Martin (Delichon urbicum). This is one of the first studies to indicate that the Long-eared Owl's nesting season diet consists entirely of birds. The main factor affecting this result is probably the fact that the owls live in an urbanised setting.     

Dietary shifts,niche relationships and reproductive output of coexisting Kestrels and Long-eared Owls

Summary Food samples of breeding Kestrels (Falco tinnunculus) and Long-eared Owls (Asio otus) were collected in the peak and low phase of their preferred prey (Microtus voles) in western Finland. Diets of pairs that bred as neighbours (1 km) with interspecifics were compared with those of non-neighbours. In both species, neighbouring pairs fed less on Microtus voles and more on alternative prey than did non-neighbours. Competition theory predicts that diet overlap should be lower during prey shortage and that diet similarity should be especially reduced in neighbouring pairs. Observations were consistent with expectations: diet similarity was lower in the low vole years and neighbouring pairs showed less diet overlap that non-neighbours. Differences in habitat composition and prey availability at the sample sites should not confuse the results. In addition to the high diet similarity, hunting habitats and nest sites of the species overlapped almost completely; they only showed clear temporal segregation in hunting. Probably because of food competition, the neighbouring pairs of both species produced significantly fewer young than the non-neighbours. These results contrast with the view that the diet composition and dietary shift of rodent-feeding predatory birds can be interpreted in terms of simple opportunistic foraging. In the breeding season, interspecific competition for food seems to be an important factor that affects the niches of these species, especially in northern areas, where the seasonal low phase of voles in spring and the number of alternative prey are lower than in more southern areas.     

山地次生林长耳鴞对喜鹊巢址的利用

1996年至 1 998年夏季 ,在左家自然保护区对长耳 ( Aiso otus)的巢位及巢树进行了系统观察和初步研究。结果表明 :喜鹊 ( Pica pica)巢址是长耳选择巢位的重要资源 ,占发现总巢数的 83%。在长耳所利用的 2 0棵喜鹊巢树中 ,蒙古栎 ( Quercusmongolica)所占的比例最大。喜鹊巢树的树种、胸径、及其附近的灌木数量等生态因子是该巢址能否被长耳所利用的重要生态指标。被长耳所利用的喜鹊巢址距农田的距离与那些未被利用的巢址差异显著。     

北京地区黑鹳越冬期的取食行为

2004年12月至2005年3月在北京十渡地区的二渡和涞水县野三坡两地采用目标取样法对越冬期黑鹳(Ciconia nigra)的取食行为进行了观察。每星期观察一次,累计观察246 h。黑鹳觅食处水深5~40 cm左右,以鱼类和螺类为食,其中鱼类占90%以上;平均每小时进食20次左右,黑鹳在两个研究地点取食的食物没有差别(P=0.439>0.05)。黑鹳取食长度小于4 cm的鱼类最多,占取食总次数的65.0%。成体和亚成体对不同大小鱼类的取食比例无差异(小于4 cm的鱼类,P=0.513>0.05;5~8 cm,P=0.979>0.05;≥9 cm,P=0.657>0.05)。在成体与亚成体对不同体型鱼类的搜寻时间中,成体搜寻较小食物的时间短于亚成体(P=0.008<0.05)。对食物的处理时间随着鱼类大小递增而延长,亚成体在处理较小食物上花费的时间相对较长(小于4 cm的鱼P=0.002<0.05;5~8cm的鱼P=0.001<0.05),表明亚成体的取食经验不足。保护越冬期黑鹳的最佳对策是减少对其取食活动和取食地的人为干扰。     

Diet of the Long-eared Owl,Asio otus,in Central Anatolia (Aves: Strigidae)

In a one-year study on the diet of the Long-eared Owl, Asio otus, in the area of Karap?nar in Central Anatolia, 5324 prey items were recovered from 3314 pellets collected at monthly intervals. At least 7 species of mammals belonging to Insectivora (Crocidura suaveolens) and Rodentia (Allactaga williamsi, Cricetulus migratorius, Meriones tristrami, Mescocricetus brandti, Microtus guentheri, M. sp., Mus macedonicus) were identified. Rodentia were dominant and contributed 93.8% of the number of prey items of the Long-eared Owl. Microtus guentheri accounted for 83.9% of the rodent remains. The diet pattern was more diverse in summer, when some 24% of the diet consisted of non-mammal prey items (birds, insects).