The secret password Australian songbirds use to identify their offspring (and catch out copycat cuckoos)
- Adelaide researchers found mother's pass on a single note to their offspring
- The young birds have to include the password in their songs to be fed
An Australian song bird uses secret passwords to prevent identity theft, scientists have learned.
When they are still in the egg, superb fairy wrens learn a unique single note sung by their mother.
Once hatched, they have to include the password within their begging calls in order to be fed.
THE SUPERB FAIRY WREN
Male Superb Fairy-wrens have been labelled as 'the least faithful birds in the world'.
Females may be courted by up to 13 males in half an hour, and 76% of young are sired by males from outside the social group.
Mother wrens also taught their mates the password, as well as trusted helpers, by singing a 'solicitation song' away from the nest.
The system is believed to have evolved to prevent identity theft by cuckoos.
Parasitic cuckoos typically lay an egg in another bird's nest which hatches early.
The young cuckoo throws out the other eggs or chicks and takes over the nest, being fed and raised by the unsuspecting parents.
In the case of the superb fairy wren, an invading cuckoo that does not produce the necessary password after hatching is likely to find itself abandoned.
'Parents and others attending the nestlings will only feed them if their begging calls contain the learned password,' said study leader Dr Sonia Kleindorfer, from the University of Adelaide in Australia.
Studies showed that when clutches of eggs were swapped between nests, newly hatched chicks produced begging calls that matched those of their foster mothers.
This was evidence that the passwords were learned.
Reporting their findings in the journal Current Biology, they wrote: 'Playback experiments showed that adults respond to the begging calls of offspring hatched in their own nest and respond less to calls of other wren or cuckoo nestlings.
'We conclude that wrens use a parent-specific password learned embryonically to shape call similarity with their own young and thereby detect foreign cuckoo nestlings.'
Natureko aipamena: http://www.nature.com/news/wrens-teach-their-eggs-to-sing-1.11779