Crows will be sent to pick up discarded cigarette butts and other forms of litter from the streets of a Swedish city.

The wild birds are being trained through a step-by-step process to pick up rubbish and place it into a machine which will dispense food for them in the city of Södertälje.

The method is part of a pilot project called 'Corvid Cleaning' by The Keep Sweden Tidy Foundation and aims to lower the costs of street cleaning in the city.

Christian Günther-Hanssen, the founder of the company, estimates the use of crows could save Södertälje, which currently spends 20million Swedish kroner (£1,601,518) on street cleaning, at least 75 per cent of costs.

He also said the wild birds were 'taking part on a voluntary basis' and were 'easier to teach' than other birds.

He told the Swedish news agency TT: 'They are easier to teach and there is also a higher chance of them learning from each other. 

'At the same time, there's a lower risk of them mistakenly eating any rubbish.' 

As part of their training the crows are taught to pick up the cigarette butts and throw them into a special vending machine.

The vending machine, which will be able to tell the litter apart from other items such as stones and leaves, will then reward the bird with food.