Vertical transmission of learned signatures in a wild parrot

Nests of wild green-rumped parrotlets were monitored continuously with cameras and microphones through chick development, and eggs were cross-fostered between nests so that some chicks were raised by parents other than their genetic ones. The contact calls chicks developed were compared with those of their genetic and foster parents.

Studied in

Forpus passerinus

Sample size

wild green-rumped parrotlet nests, including cross-fostered broods

Each chick developed an individually distinctive contact call whose features resembled those of the parents that raised it rather than its genetic parents, and parents used distinct calls when addressing different chicks before the chicks called at all.

• One small parrot species with an unusual nesting system; parrots are diverse and this is not automatically general.
• That a signature is learned does not establish what it is used for beyond individual recognition.
• Sample sizes for cross-fostered broods in the wild are necessarily small.

• Swapping parrot eggs between nests to see whose voice a chick copies

  Is a parrot’s individually distinctive contact call inherited from its parents, or learned from whoever raises it?

• Vocal learning

  Learning to produce new sounds is rare. It turns up in a handful of unrelated groups — songbirds, parrots, hummingbirds, some whales and bats, humans — and each appears to have arrived at it separately.

• Parrots

  A wild parrot chick develops an individually distinctive call that resembles the calls of whoever raised it — and swapping eggs between nests is what shows it is learned rather than inherited.