Horse and deer flies are found worldwide. More than 40 species occur in North Carolina, but only about a dozen are common. These biting flies are often encountered along hiking trails, narrow lanes and roads and at the edges of woodlands. They are numerous and annoying along the coast and near their breeding and natural feeding sites such as flood plains of swamps, streams and rivers and around ponds, salt marshes, and beaches. Females also consume nectar.
Deer flies tend to bite around the head and neck areas.
Horse flies often attack the legs. Birds are usually not attacked by these flies. Male tabanid flies do not feed on blood. Males consume nectar and plant sugars. Horse fly larvae are predaceous on small invertebrates and consume organic matter.