国家地理:Acorn Woodpecker 橡树啄木鸟（在线收听） |
| Tragedy has produced opportunity among the acorn woodpeckers here in California's Carmel Valley. The second of two breeding females in this particular communal group has been killed, probably by the birds of prey that kill one in five of the acorn woodpeckers every year. To understand where the opportunity comes in, it helps to know how a communal group of acorn woodpeckers works. They don't just wing it. Acorn woodpeckers are what scientists call cooperative breeders. This group includes co-breeder males, like this farther and son who share the job of fathering offspring. These two sisters are the clan's joint-nesting breeding females who share the job of producing the chicks. The others in the group are non-breeding helpers of both sexes who collect acorns and help out in general. In this group, both joint-nesting females have died. So these highly prized positions in the group are up for grabs. That's where the opportunity comes in. But the now deceased females have left behind two newly hatched chicks. What'd become of them? Competitors for the coveted chance to leave the ranks of helper and become a breeder arrive from all over. And once they arrive, the cooperation turns to conflict as they fight for the role. The winners are a pair of sisters, former helpers from another group nearby. The first thing they do is, kill the babies of the previous breeders. Somehow, the group accepts this without a squawk. New group, new order. acorn: The fruit of an oak, consisting of a single-seeded, thick-walled nut set in a woody, cuplike base. 橡树 wing it: (idiomatic) to improvise; to make things up or figure things out as one goes; or to perform with little or no preparation 即兴表演 father: To procreate (offspring) as the male parent. 作为父亲生养(后代) up for grabs: Available to anyone 供人竞争 deceased: No longer living; dead. 已死的 become of: Happen to, befall, be the fate of 遭遇；发生 covet: To feel blameworthy desire for (that which is another's). 非分地妄想（别人的所有物） squawk: To complain or protest noisily or peevishly. 抱怨 |
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