How Hurricanes Affect Deer Populations And Movement

Photo provided by Tyler Barron Photography.

Just like with fishing, one of the best times to hit the woods is before a low-pressure system like a hurricane makes landfall in your state. Even if your property isn’t in the direct path of the storm, its outer bands can produce winds and rain that affect barometric pressure, and, increase deer movement.

The southeastern portion of the United States is subject to frequent tropical storms and hurricanes during its active season. Storm surges and 155 MPH winds have the potential to reshape shorelines, diminish crop yields and level thousands of acres of merchantable timber; effectively ruining a deer’s habitat, you would think.

But case studies suggest, and deer hunters would concur, the whitetail is hard to kill.

While climate change has increased the frequency of extreme climatic events (ECEs) like hurricanes along the Gulf and Atlantic coast, biologists and deer ecologists have been busy studying deer movement and survival rates related to ECEs.

The common denominator among studies examining deer behavior during hurricanes: resiliency.

“They’re so resilient. From South America to the Arctic Circle, deer survive,” said Assistant Professor Gino D’Angelo with the Deer Ecology and Management and the University of Georgia. “There’s usually a few accidents; a deer might be killed by flooding or a fallen tree, but the mortality associated with hurricanes, usually does not affect deer appreciatively. They survive, they change patterns short term but beyond the initial event, often times these disturbances are phenomenal for deer habitat.”

Louisiana State University and Louisiana Dept. of Wildlife and Fisheries found no evidence that the 57 deer marked for research were affected by three tropical systems in the coastal marshes of Louisiana’s Mississippi River Delta during 2007-2012.

UGA’s Warnell School of Forestry and Natural Resources partnered with Virginia Tech and the Florida Fish and Wildlife Conservation Commission to study the behavioral response of deer to ECEs in the Florida Panther National Wildlife Refuge (FPNWR) and the northern units of Big Cypress National Preserve (BCNP) during Hurricane Irma (Category 5) in 2017.

Deer not only increased movement during Hurricane Irma, but most left their home ranges and sought higher elevation in pine and hardwood forests to weather the storm. Movement increased substantially the day of the storm, there was a depression during the event and afterward movement returned to normal. No mortality was attributed to Hurricane Irma.

“In Florida, it’s harder to find higher elevation but those deer sought higher elevation and had zero mortality. One issue, in terms of Key deer and Louisiana deer, is increased salinity in coastal environments,” Gino continued. “So, where deer are able to find fresh water and plants associated with fresh water, that can change after a storm. By in large, mortality didn’t increase at all with storm events.”

Wind-thrown trees from hurricanes open a forest’s canopy and allow sunlight to germinate the native species residing in the soil below. Although economic damage to a landowners’ timber resources looms, Mother Nature rearranging her landscape creates gaps that produce early successional habitats for deer.

“Outside the loss of mature trees to acorn production, or the cover aspect associated with mature trees, deer can live in systems that don’t have any trees,” Gino said. “When trees are removed from the landscape and we get sunlight to the forest floor, all nutrients are available for a flush of plant growth. Deer do really well in those gaps created by hurricanes.”

He continued, “As a young forest grows back, you’ve got your blackberries, sumacs and poke weed that comes in soon after the storm event. Deer rely on those areas between mature forests, ag fields and clearcuts. Because guess what’s in those gaps? Flush growth, high-protein forage, soft masts so that cover is greatly associated with food which they rely on throughout much of the year.”

Going back even further to Hurricane Georges (Category 2) in 1998 and Irene (Category 1) in 1999, researchers at Texas A&M University, University of Florida and the U.S. Fish and Wildlife Service conducted a case study on the endangered Florida Key deer in the National Key Deer Refuge (NKDR) and concluded that mild to moderate hurricanes have little to no effect on deer survival.  In fact, productivity rates doubled after the hurricanes.

Within the NKDR, 75% of deer populations live on Big Pine Key and No Name Key. BBK and NNK’s overstories were reduced nearly 50% following Hurricane Georges, which caused a short-term increase in available forage and long-term increases in understory vegetation. Female Key deer’s overall fitness increased because of added food availability and were more productive during breeding season. Surveys conducted between 1999-2000 estimate fawn:adult ratios were at 0.31, and the fawn:doe ratio recorded in post-hurricane years was 0.64.

Areas occupied by Key deer during Hurricane Georges, like Munson Island and Annette Bay (both low elevation), were completely submerged for several hours, according to a personal observation by Texas A&M researcher, R.R. Lopez. Previous studies noted that Key deer are strong swimmers, and some researchers suggested deer may have had to tread water until the surge subsided.

Out of 98 Key deer relocated during Georges and Irene, only one deer died.

Case in point, hurricanes and tropical storms are like flushing a toilet. All the water, riparian zones and habitat gets a refresher while our houses get smashed.