Among blue-footed boobies, bright blue feet are known to be important for courtship, but it seems that's not all they're good for. Researchers now find that if male feet lose colour after a first egg is laid, females reduce their reproductive efforts.
Roxana Torres at the National Autonomous University of Mexico in Mexico City and her colleagues monitored pairs of the birds (Sula nebouxii) on Isla Isabel, off the coast of Mexico. In general, boobies lay two eggs of similar weight each year, with an average delay of four days between the two. The team captured males within 24 hours of the first egg being laid and used crayons to make the foot colour of half the males duller and so less healthy looking.
The researchers found that females paired with males that returned with unsavoury feet delayed laying their second eggs and, when they did lay them, produced smaller eggs than did females with untampered mates.
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Animal behaviour: Don't you step on my .... Nature 454, 920 (2008). https://doi.org/10.1038/454920a
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DOI: https://doi.org/10.1038/454920a
