How Does a Harsh Winter Affect Wildlife?

a closeup of lynx in the wild peering out from snow at dusk

mlorenzphotography / Getty Images

Freezing temperatures and record amounts of snow can be tough on humans. Those signs of winter also make life difficult for many forms of wildlife. For some, including salmon and an endangered mussel, the worst may still be ahead because quickly melting snow could lead to heavy spring floods.

But the news isn't all bad for wildlife. Deep snows have given biologists a special opportunity to study some species such as the rare New England cottontail. Scientists are watching other creatures, such as the snowshoe hare, migratory birds and wild turkeys, to determine what impact the winter might have on their populations.

Here is an overview of wildlife in New England as the end of winter approaches and the region moves toward spring. The stories were compiled with the help of Meagan Racey, public affairs specialist with the Northeast Region of the U.S. Fish and Wildlife Service.

The New England cottontail

A New England cottontail with a radio tracking collar is released into outdoor captive breeding pen in snow
A New England cottontail with a radio tracking collar is released into outdoor captive breeding pen at the Great Bay National Wildlife Refuge in Newington, NH.

Courtesy of New Hampshire Fish & Game

The deep and lingering snow has had varying affects on a rare rabbit, the New England cottontail across its range, according to Maine Department of Inland Fisheries and Wildlife biologist Walter Jakubas. The snow, for example has helped biologists and volunteers find and study the rabbits in Rhode Island. Radio-collared rabbits there have been surviving the winter.

However, in Maine and New Hampshire deeper and longer lasting snow has made it more difficult to find rabbits because they move less and burrow under the snow. The past hard winters have been associated with a 60 percent reduction in the number of New England cottontail sites in Maine, Jakubas said. This year in New Hampshire all the radio-collared rabbits died after the heavy snows, he added.

The rabbits live in dense thickets that would normally make them hard to locate, but they leave behind clues about their presence that are particularly easy to find in fresh snow. These clues include droppings (fecal pellets) and tracks. The biologists use DNA analysis to identify the droppings as being those of the New England cottontail rather than those of snowshoe hares or the common eastern cottontail.

The snow has been so deep in places this year that the rabbits' favorite cold-weather food sources such as raspberry and blackberry plants and willows have disappeared under the snow. To help find clues to where they've been, biologists and volunteers look for gnawed tree bark and browsed twigs.

U.S. Fish and Wildlife Service biologists are teaming up with the Rhode Island Department of Environmental Management, the Nantucket Conservation Foundation and University of Rhode Island researchers to study four sites where the rare rabbits have been most recently detected in Rhode Island and on the island of Nantucket. Students from Unity College, an environmental college in Unity, Maine, have joined in the effort, too, helping with a study of New England cottontails at another site, the National Wildlife Refuge in Scarborough, Maine. These efforts are just a snapshot of a five-state monitoring program in partnership with the Wildlife Management Institute and the United States Geological Service to standardize New England cottontail data collection.

The studies this year are particularly important because the Fish and Wildlife Service is considering whether to propose adding the rabbit to the threatened or endangered species list. The deadline to make that proposal is Sept. 30. As part of the effort to make a difference for the species before that deadline, biologists have live trapped the rabbits, tagging and releasing some and bringing others to a captive rearing facility at Roger Williams Park Zoo in Providence, Rhode Island. Several of the captive-reared rabbits that have been fitted with radio collars and released on Patience Island, Rhode Island and at another site in Rhode Island are doing well despite the harsh winter, according to biologists.

A lingering danger from the persistent cover of deep snow is that it not only limits the rabbits' mobility to feed, it also inhibits the ability of individuals to escape predators. Predators that hunt for the rabbits include coyotes, red foxes, owls and, even, domestic cats.

These rabbits are also somewhat easier to find in the snow than the snowshoe hare because they remain a brownish-gray all winter. The snowshoe hare transitions to white as cold weather and snows set in. The snowshoe hare has another winter advantage than its white fur over its smaller New England cottontail cousin. They have large feet that allow them to travel further than the cottontail in search of food and and make it easier for them to outrun predators.

Bobcats and lynx


Kevin Schafer / Getty Images

One of the snowshoes hare's predators, the bobcat can have a tough time during severe winters. For at least 25 years, Maine's bobcat management system has considered heavy snows with a sinking depth of more than 10 inches to be a high mortality factor for bobcats. Some biologists have suggested that bobcats at the northern edge of their range did poorly in the deep snow during the harsh winters of 2008 and 2009 and then recovered after subsequent mild winters. It's too early to know how this winter's snows will impact populations, Jabukas said.

The severity and length of the winter, though, can provide opportunities for the Canada lynx. This lynx is typically dominated by bobcats and consequently relegated to snowier parts where their exceptionally large feet allow them to seemingly float on the snow and cover large territories. Snow track surveys next winter will help biologists understand whether lynx or bobcat ranges changed in response to the deep snows this winter.

The Maine Department of Inland Fisheries and Wildlife (IFW) continues to study Maine's lynx population to better understand their population trends and range. Maine's lynx population is a subset of the more numerous Canada lynx and continue to interact with the far-reaching Canada lynx population.

Radio-collar research of Maine's lynx show that they travel in and out of Canada, and ear-tagged Maine lynx have also been captured in Canada. One Maine lynx travelled a straight-line distance of 249 miles from northern Maine into the Gaspe Peninsula.

Another lynx was tracked using a Global Positioning System (GPS) collar from northeast of Greenville, Maine in May to Fredericton, New Brunswick. It turned around there and returned to the Greenville area, covering 481 miles from March through December.

IFW biologists are also studying white-tailed deer to learn how the winter has impacted these populations. White-tailed deer are at the northern edge of their range in Maine, and a harsh winter can severely affect deer survival. Since the 1950s, biologists there have tracked temperature, humidity and snow depth from November through April in order to determine winter's effect on deer.

Wild turkeys and owls

Two male Wild turkeys with colorful feathers feeding in the snow during winter

Jeff R Clow / Getty Images

The perpetual deep snow cover is expected to have an impact on wild turkeys, though it is too early to tell to what extent. The birds are suffering from both a lack of food and thermal cover. If they can't find food on the ground through two-to-three feet of snow, they will spend most of their time up in the trees roosting.

Maine Audubon naturalist Doug Hitchcox expressed concern for resident owls because deep snow is making it very difficult for them to find food. Hitchcox has received reports that northern saw-whet owls are resorting to stalking prey in backyards, where mice and other rodents are attracted to seed on the ground under feeders. During harsh winters, barred owls will resort to hunting along dangerous roadsides where litter can attract rodents.

Bird migration

American Woodcock bird with ruffled feathers in snow and leaves
An American Woodcock hunting for grubs in the snow as winter starts to recede.

Joesboy / Getty Images

Literature shows that the timing of bird migration is more dependent on the calendar than local weather conditions.

The danger if the cold winter weather persists late into the season is that migratory songbirds and shorebirds returning to (or passing through) the Northeast to breed could starve from a lack of sufficient sources for food. In addition, the cold weather can further tax birds that are already weak from a long migration.

The American woodcock returns to the open fields of New England very early in the spring. With all the snow on the ground, these birds may be forced to suburban environments where added stress from people and cats could force them to expend much-needed energy.

Ducks, geese and other waterfowl

Group of Canadian geese walk as a group across snowy field

Santiago Urquijo / Getty Images

Biologists in Massachusetts and Connecticut have observed that black ducks captured during this winter's banding effort have been in poor condition. During the past few years black ducks will stay put once they get to their primary wintering areas, even when the weather gets worse. There have also been reports of Canada geese in Massachusetts that have died from apparent starvation.

The barrier island habitat for endangered roseate terns and the shoreline habitat for threatened piping plovers are vulnerable to erosion. For the plover, if winter storms have washed over beach areas (creating wash over fans and blowouts), the wicked winter weather might actually improve habitat for the upcoming breeding season. The New England coast is covered in snow, and biologists say they will have to wait until it melts to assess this winter's impact on plovers.

In the streams

The Atlantic salmon (Salmo salar) is a species of ray-finned fish in the family Salmonidae. It is found in the northern Atlantic Ocean

hadot / Getty Images

High levels of snow can be good or bad for Atlantic salmon depending on how the snow melts and is released downstream. Scientists will have to wait to see how this scenario plays out this year.

One of the things they will be watching is to see how quickly (or slowly) the snow melts. If water is released slowly throughout the spring, then the streams and rivers won't be flooded and stream temperatures will remain cooler for a longer period of time, which is good for salmon. On the other hand, flooding caused by more rapid release of water can increase volume, velocity and sediment in the water, which can be very tough on young fish.

In the meantime, anchor ice, which forms on the bottom of streams on the rocks and pebbles where salmon eggs are buried and grows upward, could block the flow of water to the eggs. Water also carries oxygen that the eggs need to survive. Anchor ice can also force the juvenile salmon (parr), which hang out on the bottom in the gravel in winter, to move and expend energy when there isn't much food, thus weakening them and potentially reducing their ability to survive extreme conditions.

Snowmelt could also pose a problem for the endangered dwarf wedgemussel. Until the thaw begins, the mussel should be snug in the sediment. The concern among scientists is that if all the snow melted at once there could be serious flooding that might scour up the mussels and send them down river to places where they could not survive.

The flora

Furbish's lousewort (Pedicularis furbishiae) is a green plant with small flowers in new brunswick
Furbish's lousewort (Pedicularis furbishiae) is found nowhere else in the world except along the Wolastoq/Saint John River.

Courtesy of the Nature Trust of New Brunswick

There's good and bad winter news for the plant inhabitants of New England, too. The snow cover could be good for plants because it keeps the ground from really hard, deep freezes and protects plant roots (or rhizome in the cause of the threatened small whorled pogonia).

Jesup's milk-vetch needs ice scour on the Connecticut River to reduce invasive plants that occupy its very limited habitat on the ledge banks of the river. Because quite a bit of ice has built up on the river this winter, biologists said they will have to wait and see how the ice responds to warming temperatures. If ice clears the invasive plants from the ledge banks, biologists said they could see some great new habitat for the plant.

It is the Furbish's lousewort that is possibly in the most precarious position of New England plants this winter. This species of lousewort is an endangered plant that is found in only one place on Earth, the banks of the St. John River in northern Maine. This member of the snapdragon family lives on the river's edge and depends on periodic scouring of the riverbanks in spring by pieces of ice the size of your house!

If the riverbanks are not scoured frequently enough, shrubby vegetation like alders shade out the lousewort. If scoured too frequently, then the plant does not have time to establish and reach maturity.

Ice scouring about once every 5 to 7 years is just about right. Climate change is altering the St. John River dynamics by increasing the rate and intensity of spring floods and ice scouring. Thus, the lousewort is not as successful at establishing new populations. Biologists will have a better sense of how ice scouring affected existing populations and habitat when the Maine Natural Areas Program surveys are conducted later in the year.