What birds can teach us about courtship and nesting

The first day of spring is Sunday, March 20, and with its arrival come longer days and lighter thoughts, include around love and romance. To that end, consider taking some lessons from our avian friends.

Researchers from the Cornell University Lab of Ornithology have found an antidote for the perky Australian red-backed fairy-wren whose promiscuity (both sexes) is legendary. How to hold such feelings in check? Sing with your mate, the researchers discovered.

The study was published Feb. 24 in Biology Letters.

“The result was not expected at all,” said Daniel T. Baldassarre, PhD, one of the study authors. “In fact, we were actually looking into whether more aggressive males did better at preventing extra-pair matings with their mate than more timid males. We thought the aggressive males would be cuckolded less often.”

The scientists tested their theory with red-backed fairy-wrens just outside Brisbane in Queensland, Australia. (DNA paternity testing on the offspring from nests in the study site found 60 percent contained young sired by a male who did not share their nest.)

To test the aggression hypothesis, the scientists positioned fake fairy-wrens in the bushes and played male song recordings. Some wrens were fierce in their territorial defense, physically attacking the fake birds to drive them off. Others were wary. But in the end, it made no difference. Whether lion or lamb, on average the males got cuckolded just as often.

But in addition to measuring levels of aggression, the scientists also measured how quickly the pair began a duet and how often they sang duets after detecting an intruder. Those who reacted quickly and sang duets more are said to have a “strong” duet-singing response. Others were slower on the uptake.

“We found that pairs with a strong duet response had lower rates of cuckoldry,” said Emma I. Greig, PhD, one of the study authors. “Pairs were less likely to mate outside of their pair bond when they sang together more.”

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