The surprisingly powerful memories of blue tits and great tits revealed by University of Cambridge and University of East Anglia study

Blue and great tits recall what they have eaten in the past, where they found the food and when they found it, a study by the University of Cambridge and University of East Anglia has shown.

In the first experiment of its kind to involve wild animals, the birds demonstrated ‘episodic-like’ memory to cope with changes in food availability when foraging.

Episodic memory is a system involving the conscious recollection of personally experienced events. While many psychologists believe it is uniquely human, a growing body of evidence suggests that many animals possess episodic-like memory too.

And the same study may suggest that humans leaving out seeds and nuts for garden birds could be contributing to the evolution of these memory traits.

The researchers enabled 94 wild blue and great tits to take part in a series of memory tasks involving automated food containers and a new software program that created unique experiences for individual birds, and tracked each bird’s behaviour after they formed a memory.

The birds were fitted with unique radio frequency tracking tags that was read when they landed on the feeder’s special perch. Custom-built programs released, or did not release, food through an electronic door, according to experimental rules with unique timed events specific to each individual bird.

“These findings provide the first evidence for episodic-like memory in the wild and show that blue and great tits have a more flexible memory system than we used to assume,” said first author James Davies, from the University of Cambridge’s Comparative Cognition Lab.

Senior author Dr Gabrielle Davidson, from the University of East Anglia, said: “The birds were behaving naturally in a familiar environment, so we captured something more realistic than if the birds had been captive. It was remarkable to see these birds performed well in our memory tasks while also experiencing a bunch of other memories out in the wild.

“For us, field research is challenging because the birds are completely free not to take part in our experiments and just fly away, but we’ve shown this type of intelligence test in the wild works.”

Nicola Clayton, professor of comparative cognition at the University of Cambridge, an author of the study, and James Davies’ PhD supervisor, said: “It is fascinating that these non-caching species of birds showed episodic-like memory using two independent tests. When I began this research in the late 1990s, most psychologists assumed that the ability to remember the ‘what, where and when’ of unique past events was uniquely human.

“The initial findings in scrub-jays showed that this was not the case. Subsequent research suggests that this ability is much more widespread in the animal kingdom than we previously thought.”

The researchers suggest that having a more flexible memory may help these birds cope with further environmental stress and fluctuation influenced by climate change.

James said: “This type of memory would allow them to flexibly react to new conditions and combine this information with their original memory to make decisions. So whether they’re thinking about fruit ripening or caterpillars emerging, that’s a powerful ability to have when things get tough.”

And it thought that humans leaving out food for garden birds may contribute to the evolution of these memory traits. We know birds have evolved beak adaptations in response to increased reliance on garden feeders.

Dr Davidson said: “It is possible that these birds are picking up on and remembering our routines in terms of when we top up bird feeders. This needs further study.”