Tracey

“At Bealltainn, or May Day, every effort was made to scare away the fairies, who were particularly dreaded at this season. In the West Highlands charms were used to avert their influence. In the Isle of Man the gorse was set alight to keep them at a distance. In some parts of Ireland the house was sprinkled with holy water to ward off fairy influence. These are only a mere handful out of the large number of references available, but they seem to me to reveal an effort to avoid the attentions of discredited deities on occasions of festival once sacred to them. The gods duly return at the appointed season, but instead of being received with adoration, they are rebuffed by the descendants of their former worshippers, who have embraced a faith which regards them as demons.

In like manner the fairies in Ireland were chased away from the midsummer bonfires by casting fire at them. At the first approach of summer, the fairy folk of Scotland were wont to hold a "Rade," or ceremonial ride on horseback, when they were liable to tread down the growing grain.”
― Lewis Spence, British Fairy Origins