閱讀難度：

When bombarded by noise pollution, some male birds begin to sing higher tunes, a new study has found, the Discovery News reported. And that tonal shift makes them less attractive to females.

The findings suggest that birds must make difficult trade-offs in urban areas and places where traffic and industrial noises threaten to drown them out. Either they sing less appealing songs or tones in an effort to rise above the din, or they sing the songs that make them sound appealing at the risk of not being heard at all.

Wouter Halfwerk, a behavioral ecologist at Leiden University in the Netherlands said, "It could very well be that noise pollution is interfering with reproductive decisions by females." （點擊Discovery網站查看原文）

世間太吵鳥類被迫大嗓門

???????據美國《探索新聞》報道，一項新的研究發現，噪音的狂轟濫炸使得雄性鳥兒開始高聲唱歌。這種聲調的變化降低了它們對雌性鳥兒的吸引力。

???????鳥兒們在城市以及交通和工業噪音污染嚴重的地方必須作出一個艱難的選擇，因為噪音已經要把鳥兒的歌聲淹沒，它們要么唱得聲調缺少吸引力以壓過噪音，要么就唱一些有吸引力的歌而雌性鳥兒卻根本聽不到。

???????荷蘭萊頓大學的一位行為生態學家沃爾特·哈佛沃克說：“很明顯，噪音污染已經干擾到了雌性擇偶繁殖的選擇?！?/p>

(China.org.cn September 6, 2011)