Plain-tailed wrens sing what is perhaps the most complex and coordinated birdsong known, researchers have discovered. But you might not realize it just by listening.

“It sounds rather boring, truth be told,” said Peter Slater, a biologist at the University of St. Andrews in Scotland.

“It’s only when you realize that it’s several birds singing in a perfectly synchronized form that it becomes impressive.

“At a distance you wouldn’t know it was more than one bird.”