The Early Bird Gets the Sperm … to the Egg

What gets you out of bed in the morning? Before morning has broken, and some time before blackbird has spoken, songbirds rise for sex. And a clever

Early rising male Great Tits can get the sexy stuff over with and spend the res of the day looking fabulous.
Israel Gutiérrez/flickr

Male great tits in the control group became active about 22 minutes before dawn, but those with melatonin implants took an extra ten minutes to get going. They were no less active during the day, and they stopped for the night at the same time, a few minutes before dusk.

But those extra ten minutes cost the males dearly. Twelve percent of chicks fledged from the nests of control males were sired by another male, but 42 percent of chicks in the nests of melatonin-implanted males had been conceived with another male’s sperm.

As an early riser, I’d like to claim victory for the early birds at this point. But of course I can’t. For humans, Sex at Dawn remains niche. Many even prefer to rise early for bird watching.

The night time is where the action is for our species. Night owls tend to be more extrovert, novelty-seeking, and night-owl men (but not women) report having more sexual partners. Night-owls are more likely than early risers to be single and open to short-term commitment-free sex. Being a night owl is associated with risk-taking in women on a levels similar to males (both night-owls and early risers). Risk-taking predicts short-term sexual behaviour, suggesting that female night owls might be especially oriented toward sex.

Interesting, it’s true, but not yet the basis for any firm prescriptions. Unless you’re Charlotte Alter writing at Time Magazine. Anybody spot the implicit bias and rampant earlybirdophobia?

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