Hooting owls reveal motives of the dawn chorus


By Matt Kaplan (Image: Dominique Robert) The dawn chorus – when male birds sing their hearts out at sunrise – has puzzled biologists for almost as long as it has inspired poetry. The birds probably do it to show off to females – but is it a signal of strength from being able to sing on an empty stomach, or being tough enough to sing in the cold? Owls, whose activity patterns are the reverse of diurnal birds, could hold the answer, says Loïc Hardouin at the Chizé Centre for Biological Studies, France. Hardouin’s team recorded the song of male little owls and measured ambient temperatures over two months. They found that owls spontaneously called much more often just after dusk than later in the night. This is the first time that evidence for a “dusk chorus” has been established, says Hardouin. Hear the owl song The birds sang more in the early evening than they did later at night as temperatures got cooler, which suggests that the key message behind the display of toughness is the ability to sing on an empty stomach rather than in the cold, the team says. In another experiment, the researchers played recorded male owl hoots to male owls at different times. The owls responded less often at dusk than at other times of night. Hardouin says this is because responding to another call may lead to an aggressive encounter which may prove difficult or deadly to an owl that has only recently woken up and not yet fed. “While owls and songbirds have opposite singing periods, we think the owl dusk chorus helps us to understand songbird dawn choruses,” says Hardouin. “Our work indicates that singing before breakfast is the best time for males to reaffirm their territory and display fitness for females.” Journal reference: Behavioural Ecology and Sociobiology (DOI:
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