Beware the birds! They ARE bright enough to choose who to attack

The skies of his apocalyptic film were filled with dive-bombing, murdering birds.
But although Alfred Hitchcock's airborne killers were nothing more than fiction, scientists say they aren't as different from normal birds as we'd like to believe.
The Birds tells the story of a small Californian town whose inhabitants are attacked and murdered by aggressive flocks of birds.

Heads up: A mockingbird dive-bombs a student at the University of Florida after recognising her as a threat to its nest

In an experiment which echoed the director's 1963 thriller, researchers proved that wild birds could remember the faces of people who threatened their nests.
They could then single them out for dive-bombing attacks. The study was carried out on mockingbirds in the U.S. but British birds could be equally vindictive, the experts believe.
Mockingbirds are one of the most common species on campus at the University of Florida. They nest in trees and shrubs close to the ground.
For the study, scientists asked student volunteers to walk up to the nests and touch the edge before leaving without harming the eggs or chicks.
The same volunteers did this for several days. On the fifth day, different volunteers approached the 24 nests.
The experiment was repeated at least five times last year and scientists began to see a pattern.

Hold on to your hair: Hitchcock's classic thriller, The Birds, showed what can happen when birds turn bad

On the first day, the birds would wait until the students approached the nest before flying off and making alarm calls.
By the third day, the birds had learned the faces of their 'attackers' and would raise the alarm while the students were still some way off.
They were able to recognise the threat even when the students wore different clothes and approached from different angles.
Each day, the birds became more aggressive. Some even dive-bombed the students  - grazing their heads with their beaks.
But when a different set of students approached the nests, the birds ignored them - flying out of the bushes only at the last moment.
They also made fewer alarm calls and were less aggressive when strangers approached, found the report in the journal Proceedings of the National Academy of Sciences.
Researcher Dr Doug Levey, said: 'We tend to view all mockingbirds as equal, but the feeling is not mutual.'
It took only two visits from a student for the birds to recognise the threat. Dr Levey added: 'Sixty seconds of exposure was all it took for mockingbirds to learn to identify different individuals and pick them out of all other students on campus.
'We think that our experiments reveal an underlying ability to be incredibly perceptive of everything around them, and to respond appropriately when the stakes are high.'
The study has not been carried out on British birds - but it is likely that some of the smarter species may share the mockingbird's talent for recognising people.
The experiment is the first time scientists have shown that wild animals in their natural settings can recognise individual people.