A deer fly in the palm of a person's hand - Keep deer flies out of your home with Kona Coast Pest Control in Kailua Kona

Deer Fly

Actual Size: ½”

Characteristics: Gray or light brown in color with clear mottled wings.

Legs: 6

Antennae: Yes

Wings: Yes

Habitat: Favors damp environments such as marshes, woodland ponds, and streams; rarely enter homes or other structures.


  • Similar to horse flies; they avoid breeding indoors.
  • The bites of deer flies can be painful, causing swelling and itching. 
  • Humans can contract tularemia through the bite of a deer fly.
  • Attracted to movement; often target moving targets such as humans and animals.
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Deer Flies in Kailua Kona

Deer flies, known for their considerable size and weight, are incessant pests affecting wildlife, livestock, and humans. These insects are infamous for targeting a variety of mammals, including horses, mules, cattle, hogs, dogs, and humans. Deer flies can be identified by their dark wing bands and eyes resembling those of horse flies. An assault by just a few of these persistent flies can make outdoor work and recreational activities into a miserable ordeal.

Deer Fly Habitat

Deer flies tend to inhabit areas near water habitats that are conducive to larval development. The majority of these flies find their habitat in brushy or low-lying pasture areas near creeks, streams, or reservoirs, where the presence of damp soils supports the growth of their immature stages. While they generally avoid entering buildings, deer flies may occasionally find their way indoors. Homes or hotels featuring swimming pools may experience heightened issues with these pests, as the gleaming surfaces and quick movements can cause deer flies to become attracted to humans.

Deer Fly Behaviors, Threats, or Dangers

People may experience bites from female deer flies, as these insects have the ability and tendency to bite, causing pain in any part of the body. The resulting bites often lead to visible bleeding wounds. The application of general first-aid type skin creams may provide relief from discomfort. In rare cases, allergic reactions may manifest, presenting symptoms such as hives and wheezing. Evidence in the western U.S. suggests the involvement of a deer fly in transmitting a bacterium causing tularemia, known as deer fly fever or rabbit fever. These flies are well-known livestock pests with painful and relentless biting behavior. Always contact your local fly exterminator for help with deer flies.