Firefighters say they believe three fires on Friday night were started deliberately.
They were called into action just before midnight – firstly to a heath fire on the approach to Eary Cushlin in Dalby.
Crews from Peel and Port Erin were dispatched to deal with the blaze – on the approach they came across a second fire near the picnic site on the Sloc.
A third fire was also spotted at the top of the Sloc on the footpath to Cronk Ny Eary Laa.
The Isle of Man Fire and Rescue Service says it is working closely with the police and the Department of Environment, Food and Agriculture to track the culprits.
A spokesperson for the service says: "What may look like scrubland is often home to the Island's unique flora and fauna, and one site involved last night is believed to be a nesting site for Grouse and Hen Harriers, both species struggling for numbers on the Island.
"The Fire Service, Police and DEFA would ask all members of the public who are out and about in our beautiful countryside, to report any actions they think may be suspicious to the police."