Nightingale's Sexy Song is All About Good Fathering

For nightingales, nothing is hotter than good fathering skills. That's at least what bird experts now think after extensively studying the songs of male nightingales. Traditionally, it was thought that these songs simply told listening females about a male's health and other desirable traits. Now, they think the 'lyrics' are actually about how good a dad he'd be.

"It has long been thought that a single feature - the size of a bird's song repertoire - may be important for females during mate choice," researcher Conny Bartsch from Freie Universität Berlin, Germany said in an emailed statement. "But our study shows that, in nightingales, it is a mix of specific song features that seem to be more important in determining their paternal efforts."

"These song features have never been described before in any other species, and include the sequential ordering of songs and the use of acoustic structures that are most probably challenging to produce," she added. "We were surprised that multiple song features - instead of one 'key' song feature - were related to male feeding effort."

As far as we know, there are about 10,000 bird species in the world. Of those species, approximately 80 percent rely on good fathering to rear their chicks. For nightingales (Luscinia megarhynchos), males feed their mate while she's incubating their eggs, provide food to chicks, and defend the nest against predators. (Scroll to read on...)

This, naturally, makes a good husband and father exceptionally important for the survival of nightingale young - a revelation that caused experts to suspect that excellent fatherly instincts may be sexually selected for.

To investigate, Bartsch and her colleagues preformed field studies on 20 nightingale couples, examining the link between the quality of a male song before pair formation, and how good a parent he then was, based on the rate at which he provided food to his chicks.

Recordings of nocturnal singing, video footage of nests and chick rearing, and data from electronic tags attached to the subjects allowed the team to determine that several different song features are associated with paternal promise. An ordered song repertoire, for instance, meant a male would be more attentive to his family; and complex songs - with many different 'buzz', 'whistle,' and 'trills' - was directly linked to more efficient chick feeding.

The researchers added that ordered singing may also be sign of age and experience. It's a fatherly 'silver fox' with the voice of an angel that these lady birds are interested in. We've all heard about 'dag bod' for humans. The nightingale 'dad song' then, is nothing to be surprised about.

Study results were published in the journal BMC Evolutionary Biology.

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