Ticks are brought to your yard by deer and become infected mainly by feeding on mice. Keep deer out by planting undesirable plants, installing deer fencing or applying deer repellents. Mice like to live in stonewalls, around sheds, woodpiles or any enclosed area they can get into. Clean up brush, keep stonewalls clear of leaves, move woodpiles away from daily activity. Birdfeeders also attract deer and rodents that may drop ticks off right where you are standing.