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变色龙小鹬 Eared Grebe

(2022-01-04 22:52:48) 下一个

今天中午饭后散步,又见一身羽毛小球似的小鹬,它们在长途飞行之后,冬季抵达我的眼前时,瘦身效果显著,只有秋季养肥了的1/2,此时它们的羽毛显得格外蓬松(下图)。

这种小鹬不单是季节性的羽毛颜色变化,为方便候迁,它们的身体器官也随季节生长,或缩小。简直就是变色龙的代言鸟。

冬季我们见到它是黑灰白色的羽毛(上图);它们的春季时装(下图)

  • In the fall, almost the entire population of Eared Grebes flies to Mono Lake, California, or Great Salt Lake, Utah, to fatten up on brine shrimp and alkali flies before migrating farther south. Here they more than double their weight, and the sizes of their muscles and organs change. The pectoral (chest) muscles shrink to the point of flightlessness and the digestive organs grow significantly. Before departure for the wintering grounds, the process reverses; the digestive organs shrink back to about one-fourth their peak size, and the heart and pectoral muscles grow quickly to allow for flight. 
  • A cycle similar to that of the fall staging areas occurs 3–6 times each year for the Eared Grebe. For perhaps 9–10 months each year the species is flightless; this is the longest flightless period of any bird in the world capable of flight at all.

上面摘抄一段鸟站的资料,更多的细节有兴趣的可详见https://www.allaboutbirds.org/guide/Eared_Grebe/overview

http://tgreybirds.com/Pages/EaredGrebep.html

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