60秒科学:Backyard Feeders Driving Bird Evolution

Backyard Feeders Driving Bird Evolution
A study in the journal Current Biology finds that backyard bird feeders in Britain are responsible for splitting central European blackcap warblers into two distinct populations that may be on their way to becoming separate species. Karen Hopkin reports

We usually think of evolution as something that happens over eons, in remote places where people rarely venture. Not something that happens around the backyard birdfeeder in just a few decades. But a study in the journal Current Biology suggests that feeding birds in winter can influence their course of evolution.

The birds in this study were central European blackcaps, a common kind of warbler. In spring, they breed in southern Germany. And when winter comes, they all fly south to the Mediterranean¹. At least they used to. In the 1960s, folks in Britain started putting out seed in winter. And the blackcaps split into two distinct groups. One goes to Spain to nosh on fruits and olives, the other heads north to take advantage of the easy English pickin’s.

The two populations may even be splitting into two species. The blackcaps that winter in England tend to mate with each other when they return to Germany. So they’re starting to look different from the birds that go south. Their beaks² are longer and narrower, less suited to supping on Spanish olives. As birds of a feather, they definitely flock together. And to some degree, they have a bunch of bird-feeding Brits to thank.
 

1 Mediterranean   

adj.地中海的；地中海沿岸的

参考例句：

• The houses are Mediterranean in character.这些房子都属地中海风格。
• Gibraltar is the key to the Mediterranean.直布罗陀是地中海的要冲。

2 beaks   

n.鸟嘴( beak的名词复数 )；鹰钩嘴；尖鼻子；掌权者

参考例句：

• Baby cockatoos will have black eyes and soft, almost flexible beaks. 雏鸟凤头鹦鹉黑色的眼睛是柔和的，嘴几乎是灵活的。 来自互联网
• Squid beaks are often found in the stomachs of sperm whales. 经常能在抹香鲸的胃里发现鱿鱼的嘴。 来自互联网