SCORES & OUTDOORS: How do birds stay warm in cold weather?


by Roland D. Hallee

Last week we took a look at how white-tailed deer keep warm during those cold winter days and nights. As you remember, that was perpetrated by my watching birds at my wife’s feeders during the blizzard of February 12-13. So, let’s talk about how those little feathered friends keep warm during those times.

First of all, I was astonished as I watched the birds come in and out of the feeders during the height of the storm that dumped upwards of 24-28 inches of snow in central Maine, with winds gusting to 25-30 miles per hour.

Birds are warm-blooded animals that have a much higher temperature than humans, usually in the range of 105 degrees, as compared to our 98.6 degrees. Body temperatures can vary during daylight hours but it can challenge the birds during the night to maintain such a high body heat.

Smaller birds run more of a risk of body heat loss since they have a proportionately larger surface area on their bodies to lose heat but a smaller core volume to generate it.

Birds have different ways to maintain body heat during cold weather. Their feathers provide remarkable insulation, and many species will actually grow extra feathers as part of a late fall molt to give them thicker protection in the winter. Oil also coats their feathers to provide, not only insulation, but waterproofing.

Their legs and feet are covered with scales to minimize heat loss. By constricting blood flow to their extremities, they can also reduce body heat loss even further.

Then, there is the old standby: adding body fat reserves to serve as insulation and extra energy for generating body heat. They will gorge themselves in the fall when food sources are abundant.

Another way to produce insulation from the cold is to fluff their feathers. That enables air pockets to be created, keeping them toasty warm. Also, it is not unusual to see birds standing on one leg or crouched to cover both legs with their feathers to shield them from the cold. They also tuck their beaks into their shoulder feathers for protection, and to breathe air warmed from their body heat.

On sunny days, they will perch with their backs to the sun to maximize the exposure area of their body.They raise their wings to allow the skin and feathers to absorb as much of the sun’s heat as possible, even spreading or drooping their wings while sunning.

If you see a bird shivering, don’t worry. They do this to raise their metabolic rate and generate more body heat as a short term solution in extreme cold.

Many small birds will gather in large flocks at night and crowd together in an attempt to share their collective body heat. Even individually, they will roost in places that may contain residual heat from the day’s sunlight.

But, there is something called torpor that birds will use to conserve energy during the cold nights. Torpor is a state of reduced metabolism when the body temperature is lowered, therefore requiring fewer calories to maintain the proper heat. Birds can lower their body temperature from 22 to 50 degrees. Torpor, however, can be dangerous as reduced temperature also leads to slower reactions and greater vulnerability to predators.

Even with all of these Mother Nature-built in safeguards, mortality rate among birds can run high during extreme winters. You can help.

During winter, keep your feeders cleared of snow and filled with good food, offer liquid water, and provide shelter. You can build brush piles or protective boxes if you have no natural shelters. I think one of the reasons we have as many birds during winter as we have is because birds are attracted to coniferous trees. My wife and I have three rather large pine trees in our backyard, providing them with plenty of protection from the weather.

Mother Nature, again, provides for its creatures, large or small.

SCORES & OUTDOORS: Surviving the rigors of Maine’s winters


by Roland D. Hallee

During the blizzard that swept through our area last week, I was standing at my kitchen window, watching the bird feeders. To my surprise, even during the height of the storm, with heavy snowfall and howling winds, the birds kept coming to the feeding stations.

“Tough little buggers,” I thought while watching.

That got me to thinking. How do these animals and birds survive these harsh winters?

So, I decided to do some research on the white-tailed deer. I had recently read an article that said the “mild” winter so far made it easier for the deer to move in search of food. That all changed last Sunday and Monday. Now that there is in the vicinity of an additional three feet of snow on the ground, how will they survive the remainder of this season?

White-tailed deer have developed a set of adaptations that enable them to survive the deep snow and cold temperatures that occur in Maine. Maine is the northern-most point of their range and there are very few of them north of the St. Lawrence River. Also, the further north you go in their range, the larger the body size, as compared to their counterparts in the south.

According to Maine Department of Inland Fisheries and Wildlife biologists Joe Wiley and Chuck Hulsey, deer shed their hair in the spring and fall. The summer hair has solid shafts and lacks the undercoat, but the winter hair has hollow hair shafts, and dense, wool-like under fur, providing effective insulation.

Also, deer will alter their diet to accumulate and retain more fat under their skin and around organs, providing them with insulation and energy reserves for the months that lie ahead. The winter diet is lower in protein and less digestible than the summer diet, requiring more energy to digest and resulting in fewer calories. The stored fat is burned during winter to partially compensate for the lack of energy in the winter diet. Deer will lose weight during the winter. If winters become too long (early start and late finish) deer could run out of stored energy and die.

Fat reserves in adult does can account for up to 30 percent of their body mass in the fall.

Their winter habitat is also important. Dense softwood canopies intercept more snow, resulting in reduced snow depths. Gathering in these areas also allow many deer to share the energy cost of maintaining a trail network to access food and to escape predators.

As you would suspect, the greatest mortality in the winter is found among fawns, followed by adult bucks and then does. Severe winters can drastically deplete the fawn population, resulting in fewer young to mature into adulthood. Consecutive severe winters can have a devastating effect, by as much as 90 percent, of young maturing, depleting the adult herd.

So, should you try to help out these critters?

Although supplemental feeding of deer is usually well-intentioned, it could have some severe adverse effects. Just to touch on a few of the reasons to leave the deer to Mother Nature’s natural course:

  • Supplemental feeding may actually increase predation. Providing supplemental food sources crowds deer into a smaller area than their usual range, making it easier for coyotes and bobcats to hunt down the deer, by limiting their escape routes;
  • Feeding sites near homes may place deer in danger of free-roaming dogs;
  • Deer feeding stations may increase deer/vehicle collisions. Feeding stations near homes also place the deer in close proximity to well-traveled highways;
  • Deer could actually starve when fed supplemental foods during winter. It takes deer two weeks to adjust to new foods, and could starve in that time period;
  • Deer compete aggressively for scarce, high-quality feeds;
  • They could die from eating too much at one time;
  • Deer concentrations at feeding sites may increase the vulnerability of deer to disease. MDIFW has documented deer concentrations equal to 350 deer per square mile at some feeding sites can cause an outbreak of infectious diseases, such as the bovine tuberculosis in 1994, and more recently, the fear of introduction of Chronic Wasting Disease, which, by 2016, had only been found in deer and moose. Although CWD, a disease that causes weight loss leading to death, has not been detected in Maine, the disease, which originated in the midwest, seems to be making its way east. It is now found in 23 U.S. states and two Canadian provinces.

Finally, predation and vehicle collisions claim more deer during the winter than starvation. Mother Nature has provided well for her creatures, so just sit back and watch them go about their daily routine.

SCORES & OUTDOORS: Crows v. Ravens: is there a difference?


by Roland D. Hallee

If you remember, a couple of weeks ago I wrote about all the birds that have been coming to our feeders, and I compared the situation with the Alfred Hitchcock thriller film, The Birds. Well, I have another chapter in that episode. I have noticed recently the high number of crows, or ravens, that have been hanging around my house. Just the other day, I saw seven of them sitting in my pine trees in the backyard. They are huge birds.

Just to draw a comparison, there was a gray squirrel – either Martha or Stewart, my resident squirrels, are pretty good sized squirrels – on one of the other branches, and these birds made it look like a field mouse. The squirrel was dwarfed by these birds. They were also licking their chops. However, the crows’ stout bill is not strong enough to break through the skin.

Later that day, while driving by the park that is located at the end of my street, there were about two dozen of these birds feeding on the banking that was bare of snow.

Where are they coming from? And are they crows, or ravens like some people are calling them?

Well, to cut to the chase, crows have a fan-shaped tail, while ravens’ tails are wedge-shaped. The birds I’m looking at have a fan-shaped tail. Obviously, there are a few differences between the two species. Most of the differences are noticeable when the two are together. However, crows will assemble in large flocks, while ravens tend to be solitary, until the fall migration.

Crow, left, and Raven. Note the position of the tail feathers. The crow’s are fan-like, while the Raven’s are wedge-shaped.

Both the crows and the ravens are highly intelligent birds. Perhaps the most intelligent. The two can learn to imitate a variety of sounds, including the human voice. Recent research has found crows not only use tools, but also tool construction. Their intelligence quotient is equal to that of many non-human primates.

There is a story that indicates crows know how to count. The story has not been substantiated, but it goes like this. Three hunters enter a hunters’ blind. They wait, the crows know they are in there. The crows don’t move. Two hunters leave the blind, and the crows still don’t move. Once the third hunter leaves, the crows know they are gone and resume their normal activity.

Crows also have a good memory, remembering where there is danger, and where their cache of food is for later consumption.

Predators include owls and hawks. Crows will gather together to move an offending or intruding owl or hawk. However, West Nile disease has been taking its toll on crow populations.

A couple of years ago, while fishing on Webber Pond, my wife and I noticed a large flock of crows headed for a tree that sat on a point. Apparently, a bald eagle was intruding on a nest. The crows mobbed the eagle and drove it off. That was interesting to watch.

So, taking all these things into consideration, the large black birds hanging around my house are crows. But the question as to where they come from and why they are hanging around, has not been answered. In the past, I have seen massive numbers of crows fly overhead in late fall. But they continue in a northwesterly direction, darkening the sky as they passed. This year, they are making themselves right at home around my house.

I will continue to investigate.

SCORES & OUTDOORS: Canada lynx surviving in Maine

Roland D. Halleeby Roland D. Hallee

Recently, two Canada lynx were found dead in northern Maine, spawning an investigation into why, and who, killed the predatory cat.

The Canada lynx, Lynx canadensis, was listed as threatened on March 24, 2004, by the U.S. Department of Fish and Wildlife.

Canada lynx are medium-sized cats, generally 30-35 inches long and weighing 18-23 pounds. They have large feet adapted to walking on snow, long legs, tufts on the ears, and black-tipped tails. They are highly adapted for hunting snowshoe hare, the primary prey, in the snows of the boreal forest.

A Canada lynx in the wild.

A Canada lynx in the wild.

Lynx in the contiguous United States are at the southern margins of a widely-distributed range across Canada and Alaska. The center of the North American range is in north-central Canada. Lynx are found in coniferous forests that have cold, snowy winters and provide a prey base of snowshoe hare. Lynx, primarily found in northern Maine, prey almost exclusively on snowshoe hare, so the fate of both species are linked.

Lynx can only flourish in a large boreal forest that contains appropriate forest types, snow depths and high snowshoe hare densities. In the Northeast, lynx were most likely to be in areas that support deep snow (106 inches annually), associated with regenerating boreal forest landscapes.

Lynx are highly mobile and have a propensity to travel long distances, particularly when prey becomes scarce.

Some believe both lynx and coyotes would compete for the same food, but during a recent 12-year study, it was found that is not the case. Lynx roam the deep snow without problems, while coyotes travel more in packs along trails and road systems, and are more likely to attack larger prey, such as deer.

a snowshoe hare

A snowshoe hare, the favorite prey of the lynx, with its winter coat.

The historic and current range of the lynx in the contiguous United States is within the southern extensions of the for­ests of the Northeast, Great Lakes, Rocky Mountains and Cas­cade Mount­ains.

The lynx is listed in 14 states that support the environment needed to sustain the animal. Maine, New Hampshire and Vermont are three of them.

The environment in Maine is perfect to support Canada lynx populations. Harsh winters, deep snow, dense evergreen forests and sub-zero temperatures are exactly what the lynx likes. But, due to extensive hunting for its pelts in the 1960s, the cat nearly disappeared from Maine. Only a new law enacted in 1967, has protected it from hunting and trapping.

According to Jennifer Vashon, in charge of Maine Department of Inland Fisheries and Wildlife lynx program, it is believed the lynx population in Maine is at a historic high. More than 1,000 adult lynx are believed to be inhabiting the Maine forests. Even though it doesn’t sound like very many, compared to other fur bearing animals in the state, the lynx is actually living at the edge of its range.

Recently, a friend of mine who keeps farm animals in Richmond, reported sighting a lynx that was checking out his chicken coop.

Although the lynx was placed on the federal threatened species list, it is only listed as a species of special concern in the state of Maine.

Legal trapping, snaring, and hunting for bobcat, coyote, wolverine, and other fur-bearers create a potential for incidental capture of lynx. Lynx persist throughout their range despite the incidental catch that presumably has occurred throughout the past, probably at higher levels than presently.

Even though the animal rights group won a ruling about the state taking steps to prevent the occasional accidental trappings, they were not successful in their request for temporary suspension of some trapping where lynx are present in northern Maine.

Subsequently, inadvertent trappings of Canada lynx occur from time to time.