A council has added a new weapon to its arsenal in the fight against problem birds in Aberdeen.

Rooftops across the city will be adorned with a so-called Bird Free gel designed to deter seagulls and pigeons from nesting there.

The flourescent yellow jelly makes birds think that the rooftop is on fire and also emits a smell which is offensive to birds.

Invented by Korean bio-scientists, the Bird Free gel is being used at thousands of commercial sites across the world and has recently been introduced into the UK.

Aberdeen City Council already uses netting and spikes as deterrants for the large numbers of nesting birds, but plans to test the new gel in the near future.

Stewart Forsyth, environmental health officer, said: "It's basically an oil-based product that, when it evaporates, it emits at the UV end of the visual spectrum so to pest birds this looks as if it's flame.

"That seems to have a deterrant effect on the birds, preventing them roosting for example. It's been tried out south of the border and also worldwide. They reckon the product is effective for maybe two to four years.

"It's quite useful for ornamental buildings, like say Marischall College, because visually it's not obtrusive.

"On an annual basis we receive hundreds of complaints about gulls and pigeons. A lot of people think they are being kind feeding them. The next thing the birds do is roost on their roof. If this lives up to what it suggests it does, it will be a very useful tool."