Air Date: Week of April 29, 2011

Scientists have found that artificial night lights cause most male songbirds to sing early in the morning and that helps them attract more females. Jessica Ilyse Smith reports why early morning bird trysts may not always be ideal.

Transcript

GELLERMAN: Coming up - a city slicker with a green thumb. But first this note on emerging science from Jessica Ilyse Smith.

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SMITH: Scientists have shed light on the love life of the early bird. Not only does it get the worm, but if it’s a male songbird that lives under a streetlight, it can attract more females.

To examine the link between artificial light and the breeding behavior of songbirds, researchers in Germany listened to five species sing. When streetlights were on at night, four out of five male birds began to sing a lot earlier, and they found mates a lot more easily. For example, male Blue Tits, or chickadees, who lurked under the lights, were twice as likely to attract females.

Scientists believe the male’s early morning serenade acts as a signal to females, indicating that they are strong and virile mates. But while artificial light may increase the male birds’ chance for romance, it can also deceive the females into thinking the early birds are genetically good partners when actually, they’re not. This could lead to less vigorous chicks and problems for the species.

Scientists also suggest another downside to these well-lit early morning trysts. The birds may be tired from their nocturnal workouts and vulnerable to predation. So from a bird’s eye view, nighttime might be the right time for mating - but it’s better in the dark. That’s this week’s note on emerging science, I’m Jessica Ilyse Smith.

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Links

Read the scientific article in Current Biology.