by Roland D. Hallee

Last week I was watching a cardinal at my wife’s bird feeder and wondered how those little critters keep warm. So, let’s talk about how those little feathered friends keep warm during those times.

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.

Roland’s trivia question of the week:

Which current NFL team was originally called the Titans?

The different coats of the winter and summer ermine.

by Roland D. Hallee

Last week, I received a phone call from a reader in Palermo who told me that for only the third time in the last 17 years, he spotted an American ermine crossing his back yard.

The American ermine or American stoat, Mustela richardsonii, is a species of mustelid native to most of North America.

It was long considered conspecific with the stoat, but a 2021 study found it to be a distinct species. The finding has been accepted by the American Society of Mammalogists.

Both ermines and mink belong to the same subfamily, which contains weasels, badgers, ferrets, polecats and wolverines. These two creatures share many features, but differ in several ways.

Ermines resemble the long-tailed weasel in general both appearance and coloration, but is smaller, has a shorter tail, and has white fur on the inner side of the hind legs.

The species is found throughout most of North America aside from most of Alaska (although it is found on some islands in southeastern Alaska), eastern Yukon, most of Arctic Canada, and Greenland. It reaches the northern extent of its range in Baffin Island and a portion of eastern mainland Nunavut and ranges from here to cover almost all of western North America south to northern New Mexico, and eastern North America south to northern Virginia. It is absent from most of the Southeastern United States and the Great Plains.

The International Union for Conservation of Nature lists the ermine population as stable and of least concern.

In North America, where the ecological niche for rat- and rabbit-sized prey is taken by the larger long-tailed weasel, the American ermine preys on mice, voles, shrews, young cottontails, chipmunks, deer mice, jumping mice, and house mice. Usually the ermine kills by biting at the base of the skull. Small birds, frogs, small fish, and earthworms are other types of prey for ermines.

Ermines live and find cover from predators in hollow spaces from logs, burrows and man made structures. Ermines sometimes den within their prey’s nest and use their skin and fur as a lining for their den.

Ermines are mostly nocturnal, but may forage by day.

The ermine is listed as one of the top 100 most invasive species in the world. It was introduced to several areas to reduce rabbit populations and rapidly became a threat to ecosystems because of its vicious nature and ability to sustain itself on a variety of prey.

At one time, the ermine was sought for its attractive fur. During the winter months, the ermine’s fur turns white, making it a valuable and prized material for fur clothing. In medieval Europe, ermine fur was highly sought after for its rarity and beauty, and it was often reserved for use by royalty and other members of the nobility.

They breed in dense parts of the forest. The season for breeding is late springtime to the summer from July to August. The males mature in a year while the females only take three to four weeks to mature. The females carry a litter of four to seven babies for 255 days then gives birth.

Some of the larger wild predators of ermines are minks, martens, fishers, bobcats, coyotes, and large owls and hawks. Occasionally, a domesticated cat or dog may kill an ermine. Their small agile bodies help them evade these predators, while also allow them to compete with their predators for food in more barren months.

In spite of its bad smell and small size, however, the ermine is very self-confident, even rude – it often sits up and stares directly into the eyes of humans. Ermines do not dig its own den when they give birth, instead, they will take over old lemming burrows, food caches or graves.

According to my research, it appears that it is legal to have an ermine as a pet in Maine. However, I would advise to check with the state before owning one.

Roland’s trivia question of the week:

Which NFL team allegedly changed its geographical name in an attempt to attract a larger fan base?