You snooze, you lose paternity. That’s the message of a new study on wild birds in Germany. Males that wake up the earliest are able to sneakily mate with other birds’ partners. Males that sleep in, meanwhile, get stuck raising young that aren’t their own.
Great tits (Parus major) appear monogamous at first glance. They stick with one partner and cooperate to raise their young. But, like many other birds that scientists call “socially monogamous,” they sleep around. Great tit nests often