The moorland is internationally important for the hen harrier

Conservation group English Nature said two internationally important breeding areas for the hen harrier were wiped out in the fires, describing one of them as "intentionally targeted".

Up to 250 hectares of heather moorland were affected in the fire, within the special protection areas (SPAs) on Bowland Fell and North Pennine Moors.

On Monday, English Nature (EN) said the threat to the harrier was "dreadful news".

If it had been later in the year when the peat below was dry it could have caught fire as well Karl Vietoris

In a statement, a spokesman said: "The fire has destroyed two active hen harrier nests and possibly a third nest of a female that appeared to be settling in the area.

"At least one of the burns in the North Pennines was intentionally targeted at last year's nest site."

Sir Martin Doughty, chair of EN, said last year's breeding sites were well known.

'Majestic birds'

He said: "Hen harriers use mature heather as cover and protection when building their nests and raising their young.

"It is unlikely that they will settle and nest in these newly burnt areas without this deep heather cover."

Lancashire Fire and Rescue confirmed on Monday the fires were now under control.

Station officer Karl Vietoris, from Lancaster Fire Station, said: "The fires covered a wide area.

"But they weren't as much of a problem as they could have been, because the heather on the surface was burning.

"If it had been later in the year when the peat below was dry it could have caught fire as well and been much worse."

Last year there were seven breeding female hen harriers in England, who successfully raised 22 chicks.

However, EN said the fires have left the future of the "majestic bird of prey" in doubt.