Two signs deer have been on your property: scat (above) and tracks (below).
Keep Deer Off Your Property
Each fall and spring hundreds of blood-fed female deer ticks will drop off a single white-tailed deer. Each of these female ticks is capable of producing approximately 3,000 eggs in the spring.
Exclusion or removal of deer is fundamental to controlling deer ticks on your property or in your community. A wide variety of deer repellent compounds, deer-resistant plants, and devices are available on-line and in gardening and hardware stores. While at least temporarily useful, they will not be as effective as a deer fence.
It's important to note that that mice, chipmunks, squirrels and birds may also bring ticks into the fenced area where they will drop off, molt to nymphs and adults, respectively, and infect people and their pets.
The Connecticut Agricultural Experiment Station provides an excellent description of deer control on your property.