Clever jays switch food-finding tactics
Jays demonstrate "flexible tactics" by switching between storing food and stealing from others' stashes, scientists have found.
The woodland birds are known as the shy members of the notoriously intelligent corvid family.
But birds were observed boldly stealing food from subordinates' hiding places in the University of Cambridge study.
Researchers found that the jays' strategy was dependent on the relative social rank of their opponent.
The results are published in the journal Animal Behaviour.
Eurasian jays live in woodlands and feed primarily on acorns. Past studies by the University of Cambridge team have highlighted the birds' remarkable ability to plan for the future by storing thousands of the nuts and returning to them later.
Researchers were able to ascertain the social hierarchy of 14 birds after systematically introducing them in an outdoor aviary.
To further understand the jays' food-storing behaviour, scientists observed interactions between pairs of the birds after introducing a bowl of food, including their favourite acorns, to the test area.
"When dominant, jays in our study hid many food items, moved these items frequently and boldly approached food that had been hidden by their subordinate competitor, often stealing it in full view," said Professor Nicky Clayton who supervised the study led by Rachael Shaw.
"In contrast, when subordinate, the same jays were secretive when hiding food and when attempting to steal from others, preferring to wait until the competitor was at a distance before attempting to approach and steal their food stores."
Prof Clayton told BBC Nature that these changes in behaviour indicated that the birds were thinking about the situations.
"The flexible response to social context, both when hiding food and when stealing food, suggests that the [jays'] different hiding and stealing tactics may be based on cognitive strategies, rather than learned or innate rules," she said.
The results raise further questions about how intelligence has evolved in the corvid family.
Many species in the family, including ravens and jackdaws, are social animals; meaning that they live together in groups some or all of the time.
In the past, scientists have theorised that managing relationships within these social groups may have contributed to the birds' high intelligence.
But Eurasian jays are very territorial, emitting screeching calls and performing threatening behaviour to keep others away.
"The evidence from Eurasian jays therefore suggests that current social environment alone cannot explain the cognitive abilities of corvids," said Prof Clayton.