Sean Prendergast, chief ranger at the Peak District National Park, was speaking after the fifth fire in the area since the beginning of the warm weather.
Fire crews were called to Longnor, near Leek, during Friday evening to deal with a grass fire.
Birds are ground nesting at this time of year, Mr Prendergast said.
The previous four fires are thought to have been started deliberately. Crews are still investigating the cause of the latest fire.
News Feed from BBC News
