食物储备影响灰松鸟能否安全过冬
文章来源:未知 文章作者:enread 发布时间:2011-10-09 03:45 字体: [ ]  进入论坛
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A new University of Guelph study shows that gray jays(松鸟) hoping to survive and reproduce through Canada's harsh winters need to be able to store food in the right kinds of trees. The study appears in Oecologia and was co-authored by Prof. Ryan Norris, Department of Integrative Biology; Brian Kielstra, an undergraduate student in the Department of Geography; and Dan Strickland, retired1 chief naturalist2 of Algonquin Park in Ontario.

Unlike most birds that migrate for winter, gray jays are year-round residents in the Canadian boreal forest. In winter, they rely on berries, fungi3, insects, carcass meat(生肉) and other foods cached in nooks(隐匿处) and crannies(裂缝) of trees during summer and fall. They remember where they've stored tens of thousands of food items scattered4 throughout a territory up to 160 hectares in size.

"What is perhaps more remarkable5 is that female gray jays start breeding in mid-February when temperatures are routinely below minus 15 degrees Celsius6 and there is very little food around, so these caches are crucial not only for over-winter survival but also for successful reproduction," Norris said.

He and Strickland have studied a population of gray jays on the southern edge of their range in Algonquin Park. Records during the past 33 years show that gray jay numbers have fallen more quickly within territories dominated by deciduous7 trees, such as sugar maple8, than in areas of mostly coniferous trees(针叶树) , particularly black spruce.

The researchers thought that certain tree bark characteristics might influence the quality of food storage sites. The bark and foliage9 of boreal and subalpine tree species, for example, have antibacterial and antifungal properties that may help preserve food.

To test this idea, they simulated jay caches by attaching small food containers to different trees in the fall. Weighing the food after one to four months, they found that more remained on the spruce(云杉) and pine than on the deciduous trees.

"The evidence suggests that the resin10 production of the boreal conifers may be critically important for the survival of gray jays, especially at the southern limits of their range," Norris said. "This fits perfectly11 with our observation that the jay territories that are no longer occupied in Algonquin Park are the areas dominated by deciduous forest."

An important question still remains12: why are gray jays declining in Algonquin Park?

"We think it may have something to do with climate change affecting the quality of cached food, and we are currently conducting a series of experiments to look at this," said Norris.

The Guelph study may help in understanding territorial13(区域的) limits for other boreal breeding animals.

"If other northern-breeding or alpine-breeding species rely on cached food, then their ranges may also be limited by the ability of certain habitat types to preserve food over the winter season."



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1 retired Njhzyv     
adj.隐退的,退休的,退役的
参考例句:
  • The old man retired to the country for rest.这位老人下乡休息去了。
  • Many retired people take up gardening as a hobby.许多退休的人都以从事园艺为嗜好。
2 naturalist QFKxZ     
n.博物学家(尤指直接观察动植物者)
参考例句:
  • He was a printer by trade and naturalist by avocation.他从事印刷业,同时是个博物学爱好者。
  • The naturalist told us many stories about birds.博物学家给我们讲述了许多有关鸟儿的故事。
3 fungi 6hRx6     
n.真菌,霉菌
参考例句:
  • Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
  • The lawn was covered with fungi.草地上到处都是蘑菇。
4 scattered 7jgzKF     
adj.分散的,稀疏的;散步的;疏疏落落的
参考例句:
  • Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来,塞进文件夹里。
5 remarkable 8Vbx6     
adj.显著的,异常的,非凡的,值得注意的
参考例句:
  • She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
  • These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。
6 Celsius AXRzl     
adj.摄氏温度计的,摄氏的
参考例句:
  • The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
  • The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。
7 deciduous 992yy     
adj.非永久的;短暂的;脱落的;落叶的
参考例句:
  • Overgrown deciduous shrubs can be cut back at this time of year.过于繁茂的落叶灌木可以在每年的这个时候修剪。
  • Deciduous trees shed their leaves in autumn.落叶树木在秋天落叶。
8 maple BBpxj     
n.槭树,枫树,槭木
参考例句:
  • Maple sugar is made from the sap of maple trees.枫糖是由枫树的树液制成的。
  • The maple leaves are tinge with autumn red.枫叶染上了秋天的红色。
9 foliage QgnzK     
n.叶子,树叶,簇叶
参考例句:
  • The path was completely covered by the dense foliage.小路被树叶厚厚地盖了一层。
  • Dark foliage clothes the hills.浓密的树叶覆盖着群山。
10 resin bCqyY     
n.树脂,松香,树脂制品;vt.涂树脂
参考例句:
  • This allyl type resin is a highly transparent, colourless material.这种烯丙基型的树脂是一种高度透明的、无色材料。
  • This is referred to as a thixotropic property of the resin.这种特性叫做树脂的触变性。
11 perfectly 8Mzxb     
adv.完美地,无可非议地,彻底地
参考例句:
  • The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
  • Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。
12 remains 1kMzTy     
n.剩余物,残留物;遗体,遗迹
参考例句:
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。
13 territorial LImz4     
adj.领土的,领地的
参考例句:
  • The country is fighting to preserve its territorial integrity.该国在为保持领土的完整而进行斗争。
  • They were not allowed to fish in our territorial waters.不允许他们在我国领海捕鱼。
TAG标签: trees food jays
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