Crimes against wildlife in Britain have increased more than two-fold since last year, pushing one species to the brink of extinction, authorities say.

Examples of cruelty to wildlife include badger baiting, deer poaching, bird trapping, egg theft, general habitat destruction and hare coursing -- using dogs to chase hares by sight not scent, which is generally considered sport -- The Sunday Telegraph reported.

The hen harrier, a bird of prey, has been hunted on grouse moors to the point of extinction.

National Wildlife Crime Unit Detective Inspector Brian Stuart said the motive for such crimes appears to be money.

"We are seeking to use wider policing powers, such as the Proceeds of Crime Act, to target criminals where it hurts them most -- in their pocket," he said.

The Wildlife Trusts and other conservationists accuse police of inconsistent enforcement tactics, giving offenders a sense they will not be prosecuted, the Telegraph said.