Stockholm - A theory in play that nesting birds may be partly to blame for spreading forest fires has been disproved, reports said Monday.

The theory, akin to the mythological firebird or phoenix, was mentioned last week in connection with a large forest fire in Mjolby, southern Sweden.

"The birds roost on their nests for the longest time. When the fire and heat forces them to fly off it is too late. They catch fire, fly a little and fall down like a torch," Arne Gustavsson, head of the fire service in Mjolby, was quoted as telling the Ostgota Correspondenten newspaper.

Goran Andersson, a guide at the Ottenby bird observatory on the southern tip of the Baltic Sea island Oland, read about the theory and decided to conduct his own experiment to test it.

Andersson collected feathers along the beaches of the island and took them to a warehouse where he set them alight.

"Feathers and down that are kept still after been set alight burn well, but as soon as you move them the fire dies out. I can only conclude that burning or running birds can't spread fire although they can burn up," Andersson told the newspaper.

Gustavsson later said he had not personally seen any birds flying off in flames but had read about it somewhere, but after hearing of the test said he was convinced that the theory was wrong.

"The fire could have spread through sparks," he said. (dpa)