而且，健康状况、羽毛颜色等特征不同的雄性鹩莺，在鸣叫这种行为上也没有太大区别。

What's more, there are no obvious differences in male wrens' singing behavior based on other physical traits such as health and color.

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黑头莺在欧洲一种常见的候鸟，它们生活在很多公园里，实际上它们曾经并没有禽虐感染，但是1999年的一项研究显示，几乎4%的黑头莺感染了这种疾病。

The blackcap (Sylvia atricapilla), a migrant bird common in Europe that breeds in gardens, once had virtually no avian malaria but a study in 1999 showed nearly 4% had the disease.

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这样，它们渐渐和那些到了冬季往南飞的黑头莺们在外表上出现差异，它们的鸟喙显得更狭长，这种形状的鸟喙在啄食西班牙的橄榄时可是大大不便。

So they're starting to look different from the birds that go south. Their beaks are longer and narrower, less suited to supping on Spanish olives.

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