英語(yǔ)時(shí)差：為什么雄鳥(niǎo)如此多嬌
Don: Ummm! I dunno, Ya?l. So drivers can see it when it crosses the road.
Y: Nice try, but males birds are more brightly colored and have more ornamented feathers than females for two reasons. First, so they can compete with each other for territory. Second, so they can attract mates.
D: How do they do that?
Y: Males use feather color to warn potential rivals that they occupy a piece of territory. Red-winged black bird males flash hidden red feathers on their upper wings called epaulets. Scientists have found that when a male's epaulets are dyed black, he is more likely to lose his territory.
When it's time to mate, male birds show off their plumage to attract a mate. In experiments, female house finches prefer to mate with redder males while female pea fowl like males with big tails. Scientists think females use male feather color and condition as a way to determine if he is healthy or will take good care of their nestlings. For example, redder cardinal males make better fathers by taking on more of the feeding responsibility.
D: So, fancy feathers mean a bird's healthy?
Y: Yes. That is the case with the Pied Flycatcher where males can be colored brown to black. Scientists have found that the more food a nestling receives, the bigger and healthier it is, and the blacker its color. Light feather color can also indicate disease. Chickens with a parasite known as coccidia are less colorful than healthy birds.
D: I understand now. If I want to attract the ladies, I should wear red Hawaiian shirts.
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