作者：Jim Daley 翻译：小婧
BIOLOGY
Vicious Woodpecker Battles Draw an Avian Audience
研究橡果啄木鸟权力斗争的生物学家并不是唯一的观察者，而（橡果啄木鸟的）竞争对手啄木鸟团体也是观察者
Biologists who study acorn woodpeckers’ power struggles are not the only ones watching—so are rival woodpecker groups
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Acorn woodpeckers storing acorns in a tree. Credit: William LeamanAlamy
美国西部的橡树森林被分割成不同的区域，这些区域经常被成群的橡树啄木鸟（acorn woodpeckers）激烈争夺。在每块区域里，一代代的鸟儿都把橡树转变成储存成千上万橡子的谷仓。它们在有繁殖和无繁殖的成员中筑巢，共同合作抚养雏鸟。当一对正处繁殖时期的橡树鸟中的一员死亡时，与之竞争的非繁殖橡树鸟的队伍会从周围的领地中冲进来，为填满这个鸟巢争夺机会。（应该就是让那孤寡的鸟重新交配从而继续繁殖后代）(¬_¬)这种持续数天，涉及到多个联盟间的战士自相残杀的斗争可能是致命的。科学家们研究这种战斗已经超过50年了，但直到最近他们才发现其他啄木鸟也在敏锐地观察着这些战斗。
The Americas’ western oak woodlands are fragmented into territories that are often fiercely contested—by groups of acorn woodpeckers. In each location, generations of the birds have transformed the oaks into granaries that store thousands of acorns. They nest in groups of breeding and nonbreeding members, which cooperatively raise chicks; when one member of a breeding pair in a granary-rich area dies, rival teams of nonbreeding birds sweep in from surrounding territories to fight for a chance to fill it. These internecine struggles can be deadly, involve multiple coalitions of warriors and last for days. Scientists have studied the skirmishes for more than 50 years—but they only recently discovered other woodpeckers were keenly observing the battles, too.
史密森尼国家自然历史博物馆（Smithsonian National Museum）的鸟类生物学家Sahas Barve是最近跟踪这一行为的一项研究的主要作者，其研究结果发表在《当代生物学》 Current Biology上。他和他的同事们在几十只鸟身上安装了超轻型太阳能无线电跟踪器，监测它们但位置及行踪，从而发现了鸟儿们但“旁观者现象”。Barve说道：“鸟群中的位置权力争夺是如此的混乱以至于你从视觉上无法真正跟踪每一只鸟的行动。”
Sahas Barve, an avian biologist at the Smithsonian National Museum of Natural History, was the lead author of a recent study that tracked this behavior and was published inCurrent Biology. He and his colleagues discovered the spectator phenomenon by fitting dozens of birds with ultralight solar-powered radio trackers and monitoring their positions. “Power struggles are so chaotic that you can’t really [visually] track the movements of any one animal,” Barve says.
橡树啄木鸟在打斗
生物学家已经看到：有重新繁殖机会的消息会以令人诧异的速度传播开乃至贯穿森林。没有参与这项研究的普林斯顿大学进化生物学家Christina Riehl说：“因为动物没有语言，我们通常会认为他们（相较于人类而言）更难传递信息。它们不会信息贴在Facebook上，也不会在大街上谈论它。”研究人员至今还不明白周围地带的啄木鸟是如何发现这些可以在几分钟内引发争斗的“缺口”的。
Biologists have seen news of a breeding opportunity travel through the woods with astonishing speed. “Because animals don’t have language, we often assume it’s harder for them to transmit information,” says Christina Riehl, an evolutionary biologist at Princeton University, who was not involved in the study. “They’re not posting about it on Facebook or talking about it in the streets.” Researchers do not yet understand how woodpeckers in surrounding territories find out about these openings, which can trigger battles within minutes.
令研究人员惊讶的是，这些“战斗”不仅吸引了战士（参与打斗），还吸引了显然只是为了观看（“吃瓜”）的鸟类——有时这些鸟是从几公里外飞过来的且一次观看的时间长达一个小时。这些“旁观者”让自己的谷仓处在毫无任何戒备的状态，这表明他们可以从竞争对手的联盟中获得情报，其价值超过自己收集情报所冒的风险。Riehl说：“它能帮助你判断在特定情况下该怎么做。”
The researchers were surprised that the combat attracted not only fighters but also birds that apparently came just to watch—sometimes from kilometers away—for up to an hour at a time. These spectators left their own granaries undefended, which suggests that the value of the intelligence they can gain about rival coalitions outweighs the risks of gathering it. “It helps you judge what you should do in a given situation,” Riehl says.
橡树啄木鸟中的“吃瓜群众”
Barve说：“观察其他群体中的个体之间的关系(生物学家称之为“三合一意识”)在鸟类中很少见。”新的观察研究表明，啄木鸟对社会动态有很高的理解。他补充道：“这凸显出对于动物如何感知和驾驭复杂的社会系统，我们还知之甚少。”
Monitoring the relationships between individuals in other groups (a trait biologists call triadic awareness) has rarely been seen among birds, according to Barve. The new observations show that the woodpeckers “have a very high-level understanding of social dynamics in their population,” he says. “It highlights how much we don’t know about how animals perceive and navigate a complicated social system.”
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原文出处：https://www.scientificamerican.com/article/vicious-woodpecker-battles-draw-an-avian-audience/
