CROWS could be turning savage in Waltham Forest, a resident has warned.

Concerned Guardian reader Maggie Harding described a scene in Larkswood, Chingford reminiscent of Alfred Hitchcock thriller The Birds.

She said: "My husband has noticed increasingly aggressive behaviour by groups of crows in Larkswood, first attacking and killing another crow, then attacking a small dog."

Mrs Harding then described how about 20 of the birds chased a heron into a tree, before "dive bombing" it and killing it.

"It was a mistake for the heron because the branches and leaves were hindering its escape. The sound was deafening," Mrs harding said.

"They hacked this poor heron to pieces. It fell dead from the tree."

And the RSPB have confirmed that while it is not common for crows to behave in this way, it is not unheard of.

A spokesman said: "I'm afraid it's an example of nature 'red in tooth and claw' as Tennyson said. I witnessed a couple of crows chasing off a heron over Walthamstow Marshes just last week.

"You could say the crows are particularly aggressive at the moment because they have young. They are fiercely territorial so will chase away other crows and anything they see as a threat."

He also explained that herons are probably not a threat but because of they are much larger, they are still perceived as a danger and may be attacked.

The spokesman added: "It is unusual for crows to kill the animal they are chasing away. Normally, this 'mobbing' behaviour just results in the victim being chased off. However, this heron unfortunately got trapped in the tree.

"Dogs, cats and birds of prey may also be mobbed by crows and also gulls, which also regularly mob herons and other perceived threats."

Traditionally associated with death and doom, groups, or "murders", of crows have been known to attack humans in parks and open spaces.

In 2005, two crows swooped on 44-year-old Justin Keay as he jogged through Battersea Park, leaving him requiring hospital treatment.

And in March this year, 89-year-old Ronald Milton, who lives in Gloucestershire, resorted to installing nets around his home after suffering repeated attacks from the troublesome birds.

To find out more about 'mobbing', visit the RSPB website