Song Birds - Sounds Wild
Pacific Wren


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Pacific wren

On a damp, March day in Southeast Alaska, the cheery song of the Pacific wren is a welcome sound in the chilly rainforest. Some Pacific wrens migrate south in winter, but many stay and overwinter in Alaska, and in fact this tiny bird used to be called the winter wren. In 2010, winter wrens found in the western United States, the eastern United States, and in Europe and Asia were split into three different species. The wrens in the eastern US retained the name winter wren, those in the west became Pacific wrens, and those in the old world are now called Eurasian wrens.

Although these tiny brown birds all look the same, biologists have long observed that their songs are noticeably different. The song of the eastern wrens are slower, lower pitched, and more repetitive than western wrens, and western wrens sing dozens of variations of their faster, burbling song, with trills and down-slurred whistles the eastern wrens lack.

The great ice sheets and glaciers of the last ice age divided a lot of animals and birds into western and eastern populations. Over tens of thousands of years of separation, differences between the groups became more and more pronounced - a process known as speciation. But there's more going on with the wrens -their DNA shows that the winter wren and the Pacific wren last shared a common ancestor more than four million years ago, long before the ice ages separated them. The combination of genetics and behavior convinced scientists that these birds merit new names and their own species designation.