White-tailed Deer Biology

A female deer, or doe, with her fawn, browsing in the maritime forest at Watch Hill. Does give birth to usually one or two fawns in mid- to late-spring.

White-tailed deer (Odocoileus virginianus) are the most widely-distributed large mammal in North America. While native to Atlantic barrier islands, they were not numerous on Fire Island when the park was established in 1964. However, their numbers have increased dramatically since that time, along with issues relating to an overabundance of deer: their impact on native and cultivated vegetation and forest regeneration, their role in disease ecology, and deer-human interactions on Fire Island.

Deer can be found across Fire Island: from the Fire Island communities on the western end of the island, to the undeveloped Otis Pike Fire Island High Dune Wilderness on the eastern end. Deer also live and forage at the William Floyd Estate, on Long Island.

 

Basic Deer Biology

White-tailed Deer Populations

 

Deer behind the dunes in the 1,380-acre Otis Pike Fire Island High Dune Wilderness, where current deer density is about 12 DPSM.

White-tailed Deer Populations

Deer population studies at Fire Island National Seashore reveal that there are approximately 300-500 white-tailed deer on Fire Island, and about 140 deer at the William Floyd Estate.

Deer density, or the number of deer per square mile (DPSM), varies widely between locations on Fire Island. (This number is frequently provided as "deer per square kilometer," or deer/km², in many studies. For a long, narrow landform like Fire Island, each square mile may be the equivalent of 3-5 linear miles of the barrier island, depending upon its width.)

At the 613-acre William Floyd Estate, deer density is about 140 DPSM or 54 deer/km².

The number of deer, however, is not as important as the impacts related to their abundance and distribution.

So, where are all the deer? White-tailed deer are crepuscular. That means that they are typically active at dawn and dusk, and may be out of sight during the middle of the day.

Learn more about ire Island Ntional Seashore's Deer Population Studies and White-tailed Deer and Vegetation Management Plan.

 

Bucks use their antlers to spar with other males during the rut.

Photo by Diane Abell

Basic Deer Biology

The breeding season (or "rut") for white-tailed deer in New York occurs from October to January, with peak activity occurring in mid-November.

Male deer, or "bucks." can be identified during the breeding season by their antlers, which they grow and shed annually. Antlers consist of bone, cartilage and blood vessels, and are covered by a living tissue called "velvet." The growth and shape of antlers depends largely on nutrition and genetics. Antlers remain intact for mating displays and territorial defenses throughout the breeding season.

 

Doe and her fawn in late June on Fire Island.

The female deer, or does, give birth to usually one or two fawns in mid to late spring. occasionally, triplets or quadruplets are born.

White-tail deer may live from 6-10 years in New York, but may live longer on Fire Island because they have no natural predators. Unchecked, deer may double their population numbers every 1½ years.

Their weight can range from 110 to 300 pounds. Deer are herbivores, eating a wide variety of vegetation. As they browse, deer can affect the abundance and composition of plant species in their habitat.

 

Bucks in field at William Floyd Estate, late November.