For a great example of complex co-parenting, perhaps we should be looking to wildlife – in particular, seabirds.
A new study published in The Auk: Ornithological Advances describes the collaborative parenting efforts of the common murre (Uria aalge) – a thin-billed seabird found in the cooler waters of the northern hemisphere.
While brooding their young, a pair of common murres share their roles throughout the day – one stays at home looking after chicks while the other leaves the nest to forage for food – but this isn’t the interesting part.
Fascinatingly, parenting murres have developed a complex language exhibited through preening, to let each partner know how the other is faring, and whether rest is needed.
The research team studying murre reproductive behavior in Witless Bay, Newfoundland, observed a surprising variety in the nest behaviours of parenting birds – in particular, the swapping over of duties, or ‘nest relief’, between parents.
“Some nest reliefs were short and businesslike, while other nest reliefs seemed to involve a lot of interaction between the mates, and it took a long time for the mates to exchange brooding duty,” explains study co-author Carolyn Walsh, a behavioural scientist at Memorial University of Newfoundland.
The team then observed 16 pairs of murres over one summer, recording their nest-relief processes and periodically measuring their body weights. The results indicate the preening ceremonies preceding role-swaps took longer when one bird was especially low in body mass.
This suggests a nesting bird can delay preening to let their partner know they’re not ready to take over foraging, with the returning forager perhaps pulling a double shift to give their mate more rest time; conversely a nesting bird might let a tired partner take a rest even if they have returned from foraging without food.
It’s a level of open communication that would not go astray among humans.