By JULIE WHELDON, Science Correspondent

Last updated at 22:25 06 November 2006

The insult of 'bird-brain' is generally applied to scatty people who cannot hold much in their heads.

But it seems this may be doing an injustice to our feathered friends.

Scientists have discovered that the common pigeon actually has an astonishingly good long-term memory.

In tests they found a single bird can memorise 1,200 pictures.

The team said that, despite clear physical differences between birds and other animals, there are important similarities in the way their memories work.

They therefore concluded that the processes that drive the way we store and retrieve memories appear to be largely the same throughout the animal world.

Anyone who has seen squirrels dig up nuts will know they have some long-term memory.

But to date no-one has actually challenged different species to see just how much they can learn.

The new study, published in the Proceedings of the National Academy of Sciences (PNAS), set out to do just this with two species - pigeons and baboons.

Each species was given tests in which they were shown a picture and then given a choice of two possible responses.

For example if shown a picture of a lamp they might then get shown a red and green key - one of which has been randomly selected by a computer as the 'correct' label for the image.

To train them, the birds were given a food reward if they correctly pecked the key that matched the image.

Baboons were given a similar test but had to push a button instead.

Both species were tested over the course of several years to see just how much they could remember.

To the amazement of the scientists from the Mediterranean Institute of Cognitive Neurosciences in Marseille, France, the pigeons were able to memorise up to 1,200 pictures and the correct responses.

Baboons performed much better with some managing to remember 5,000 successfully.

Despite the difference in the capacity of their memories, the researchers noted some key similarities in their reaction times and rate of forgetfulness.

'In our task the two species only differed in terms of their absolute long-term memory capacity,' they concluded.

Lead researcher Joel Fagot said the study provided important new information on how memory systems have evolved.

'Birds and monkeys differ considerably in physiology and evolutionary history,' he said.

'Despite millions of years of divergent evolution they demonstrate highly similar memory profiles.'

He concluded that the different paths species set out on hundreds of millions of years ago 'may have mainly changed memory capacities but have had little impact on basic memory processes and memory dynamics.'

The study is not the first to shed light on some of the remarkable abilities of pigeons.

Italian researchers have found they owe their sense of direction to 'odour maps' they make of areas they pass over.

Last year scientists also attempted to rate the intelligence of a whole range of birds.

They found crows, rooks, jays and ravens topped the lead for bird IQ - however the New World quail was crowned the dunce of the avian world.