Ian Hopkins from Rothesay, told the Buteman: “This is the third large, uncontrolled fire in this area in the last four years, which would suggest it is hardly accidental.
“It is also, by far the largest. I would estimate that roughly one-fifth of the island was affected, including the North Bute Site of Special Scientific Interest. This designation is mainly because it contains the best examples of upland habitats and upland oak woodland on the island.
“Together, these habitats support a wide variety of breeding birds, with up to 70 species recorded.
“Some of these species like Hen Harrier, Merlin, and Short-eared Owl require long, rank heather to nest in.
“This now all looks like an ash desert. No doubt nature will eventually restore it, but it will take years to bring it back to what it was. However, it will never recover if we keep having these uncontrolled fires!”
A Scottish Fire and Rescue Service spokesman said it was alerted to a fire at Balmakailly Hill at 2.36pm on Friday, adding: “Two appliances and crews extinguished the fire before leaving the scene at 4.57pm. There were no casualties.”