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亲鸟递食位置可以调控雏鸟之间的竞争,而异步孵化会使不同孵出顺序雏鸟的体况产生等级差异。雏鸟可以通过竞争巢中有利位置来获得更多的食物资源,从而提高自身生长发育速度和存活率。本研究于2013和2014年两年的4至8月对甘肃安西荒漠保护区桥子片区22巢荒漠伯劳(Lanius isabellinus)的递食行为进行研究。结果发现,荒漠伯劳亲鸟递食的位置主要集中在1个(n = 13,比例超过50%)或2个(n = 9,合并比例超过60%)位置上,具有一定的可预测性;处于亲鸟递食位置直线方向上的雏鸟获食次数显著高于两侧位置(n = 22,P < 0.001)。但异步孵化雏鸟的孵出顺序与其在巢内占据直线(df = 4,F = 0.211,P > 0.05)和两侧位置(df = 4,F = 0.068,P > 0.05)的次数都不具相关性;并且不同孵出顺序雏鸟间平均获食次数无明显差异(df = 4,F = 0.090,P > 0.05);拟合不同孵出顺序的雏鸟生长曲线发现,不同孵出顺序雏鸟的体重生长率也没有表现出明显差异(df = 4,F = 0.637,P > 0.05)。研究结果表明,荒漠伯劳亲鸟趋于固定递食位置并向直线方向递食;但雏鸟间具有较小的同胞竞争,出飞等级差异不显著,这可能与繁殖地短暂的食物丰富度和雏鸟本身对于乞食与获食之间的利弊权衡有关。 相似文献
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Capsule Dummy birds placed on artificial nests increase nest survival, and their use should be considered in future studies of nest predation. 相似文献
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棕背伯劳羽色多态现象探讨 总被引:6,自引:0,他引:6
羽色多态现象的研究对了解物种的遗传、变异和进化有着重要意义。棕背伯劳(Lanius schach)具有典型的羽色多态现象。结合华南濒危动物研究所馆藏标本和2005年4月—2007年1月间的野外调查,分析棕背伯劳棕色型和黑色型在形态和地理分布上的差异性后,得到的结果如下:1)广东可能存在与棕色型、黑色型相区别的一种新色型——黑色白边型,该色型全身以黑色为主,但具多枚白色飞羽;2)棕色型与黑色型各身体量度均无显著性差异(P>0.05);3)野外种群中棕色型为优势色型,黑色型多集中于沿海地区而山区未有发现,黑色白边型仅在沿海的海丰县被发现。据此认为新色型的出现说明沿海可能是黑色型分化的重要地区,且色型的分化仍在进行中。 相似文献
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I investigated seasonal changes in the relationships between brood size, body mass of nestlings and body mass of parents of the bull-headed shrike, Lanius bucephalus, in Ishikari, northern Japan. When the broods were 12days old, the body mass of the heaviest nestling in a brood did not differ among brood sizes, or throughout the season. However, the body mass of the lightest nestlings in a brood was different among brood sizes. The body mass of the lightest nestling in five- and six-nestling broods decreased throughout the season. The lightest nestling in four-nestling broods, and the lightest and the second lightest nestlings in five-nestling broods, were significantly lighter than the heaviest nestling in broods of this size. It is likely that pairs with six nestlings at 12days old can feed at least five of these nestlings enough to ensure their survival . The standardized body mass of parents (SBM), which was defined as the body mass divided by the length of the tarsus, did not differ among brood sizes, or throughout the season. It is possible that the relationship between the constancy of the SBM and the seasonal decline in the body mass of nestlings indicates that bull-headed shrikes have a limit to their parental efforts. 相似文献
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The loggerhead shrike (Lanius ludovicianus), a songbird that hunts like a small raptor, maintains breeding populations on seven of the eight California Channel Islands. One of the two subspecies, L. l. anthonyi, was described as having breeding populations on six of the islands while a second subspecies, L. l. mearnsi, was described as being endemic to San Clemente Island. Previous genetic studies have demonstrated that the San Clemente Island loggerhead shrike is well differentiated genetically from both L. l. anthonyi and mainland populations, despite the fact that birds from outside the population are regular visitors to the island. Those studies, however, did not include a comparison between San Clemente Island shrikes and the breeding population on Santa Catalina Island, the closest island to San Clemente. Here we use mitochondrial control region sequences and nuclear microsatellites to investigate the population structure of loggerhead shrikes in the Channel Islands. We confirm the genetic distinctiveness of the San Clemente Island loggerhead shrike and, using Bayesian clustering analysis, demonstrate the presence and infer the source of the nonbreeding visitors. Our results indicate that Channel Island loggerhead shrikes comprise three distinct genetic clusters that inhabit: (i) San Clemente Island, (ii) Santa Catalina Island and (iii) the Northern Channel Islands and nearby mainland; they do not support a recent suggestion that all Channel Island loggerhead shrikes should be managed as a single entity. 相似文献
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Summary Modern agriculture contributed to the decline of many bird species through habitat degradation or habitat loss during the second half of the 20th century in western Europe. Areas where traditional agriculture has been maintained still allow many species to breed and survive, some of them now being considered as greatly threatened. The Lesser Grey Shrike (Lanius minor) is among the most threatened breeding bird species in western Europe. In France, a relict population of 50–60 pairs still breeds at two sites in the Mediterranean area where, each year, the species spends the three months necessary to conduct its breeding cycle (this shrike is a long-distance migrant overwintering in southern Africa). The pairs nest in tall trees, isolated or in rows and, more importantly, depend on vineyards associated with grassy fallows. In one of these two sites west of Montpellier (Mediterranean France; 43°36N, 3°53E), a study of the land use around the nests showed the predominance of vineyards (range: 37.3 %–79.8 %) followed by fallows (10.8 %–48.2 %), and small orchards and gardens (0.5 %–7.5 %). What seems essential is that vineyards and fallows occur in a mosaic arrangement of small plots. Birds take their prey in both habitats but mostly in fallows. To secure the conservation of this shrike and other species sharing the same breeding habitats, efforts should be made to maintain the mosaic land use system prevailing in that wine-growing area.
Ein Weinbaugebiet beherbergt eine Reliktpopulation des Schwarzstirnwürgers (Lanius minor) im mediterranen Südfrankreich
Zusammenfassung Durch Habitatszerstörung oder -schwund hat die moderne Landwirtschaft am Populations-zusammenbruch vieler Vogelarten in der 2. Hälfte des 20. Jahrhunderts massgeblich beigetragen. Diesbezüglich zählt der Schwarzstirnwürger (Lanius minor) zu den am meisten gefährdeten Arten in Westeuropa. In Frankreich brüten insgesamt noch etwa 50–60 Paare, die sich auf zwei Gebiete im mediterranen Süden verteilen. Die Art verweilt dort etwa drei Monate (Mai-Juli) und ist ein Langstreckenzieher, der im südlichen Afrika überwintert. Der Lebensraum dieser Brutpaare besteht aus vereinzelt oder in Reihen stehenden Nistbäumen in einem mit grasigen Brachflächen durchsetzten Weinbaugebiet. In einem der zwei noch bestehenden Brutgebiete (westlich der Stadt Montpellier; 43°36N, 3°53E) wurde die Landnutzung in einem Umkreis von 500 m um 27 Nester näher untersucht. In den untersuchten Brutrevieren überwiegt Weinbau (37,3 %–79,8 %), gefolgt von grasigen Brachflächen (10,8 %–48,2 %) sowie Klein- und Obstgärten (0,5 %–7,5 %). Wichtig erscheint das mosaikartige Vorkommen von kleinparzelligen Weinbau- und Brachflächen. Die Vögel beziehen ihre Nahrung aus beiden Habitaten, hauptsächlich aber aus den Brachflächen. Diese Art von Landnutzung ist unentbehrlich für die weitere Erhaltung des Schwarzstirnwürgers als Brutvogel in Frankreich.相似文献
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