評論
打印
Depending on the species, bird eggs can be any color rangingfrom chicken's plain white to a robin's blue, streaked, spotted,bright, pale, and anything in between.
不同鳥類蛋殼的顏色千差萬別，雞蛋是純白色，知更鳥蛋是藍色，其它蛋殼的顏色迥異：有條紋的、有斑點的、亮色的、淡色的或者是介于之間的。
We take a look at someof the reasons this might be the case.
那么，讓我們看看顏色不一的原因吧！
But first, how do eggs get their color?
那么，蛋殼的顏色是如何形成的呢？
As the egg moves downthe female's oviduct, the tube that connects the ovary to the outside, it squeezes against glands that produce colored pigments that combine to form every color in the egg shell spectrum.
鳥蛋經由母體的輸卵管排出，分泌色素的腺體受擠壓，給蛋殼著色。
If the egg is stationary at the time that it comes in contact with these glands, it'll bespotted.
如果此刻鳥蛋是靜止的，觸碰腺體的蛋殼形成斑點； If the egg is in motion, it will be streaked.
如果是運動的，蛋殼形成條紋。
So why go through all the trouble of producing colored eggs?
為什么那么大費周章地形成不同色彩呢？
For many species of birds that nestout in the open, the eggs' colors help to conceal them by enabling them to blend into the back ground.
一些鳥類的巢在露天野外，蛋殼的色彩有助于和外界混為一體，便于隱藏。
Another way that colored eggs come in handy, is that in some species, like murres,individual birds learn to recognize their own particular markings and reject eggs that don't match.
蛋殼顏色還在某些地方能排上用場：例如海鴉，通過蛋殼顏色來識別，排除它類。
In contrast, birds that nest in cavities, or that start incubating as soon as the egg is laid andconsequently don't need to hide their eggs, tend to lay unmarked white ones.
另外一些鳥類在樹洞中筑巢的，或下蛋后馬上孵化的；鳥蛋不用隱藏，蛋殼顏色通常是白色。
Given all this, how do scientists explain the fact that robin's eggs are an eye-catching, unmarkedblue?
終上所述，科學家如何解釋知更鳥蛋是耀眼的純藍色呢？
Perhaps this enables robins to spot when a parasitic bird tries to add its own eggs to the nest.
也許這樣便于知更鳥識破其巢寄生的鳥類將自己蛋放進知更鳥巢吧！
For some species, this may pose a greater threat than that of nest robbers.
巢寄生的行為對其他鳥類更具威脅性！
