A Northwoods Almanac for 1/19/18

A Northwoods Almanac for 1/19 – 2/1/18  

The Cold Facts

            We certainly experienced a cold stretch of weather over the last 3+ weeks, though the forecast for this weekend is a warming trend. Two thoughts about the cold we had: one, the -20° that we hit a few times is not particularly extreme for northern Wisconsin. Zone 3 for gardening and farming is defined as winter temperatures reaching between -30° and -40°, while zone 4 temperatures stretch between -20° and -30°. So, -20° barely puts us into zone 4. Our area, at least until the last decade, had always been designated as zone 3. Now that our winter extreme temperatures have moderated, we’re considered zone 4.

            My second thought regards the relationship between snow cover and intense cold.

Fresh, uncompacted powder snow typically is 90 to 95 percent trapped air. Many small animals take advantage of snow's insulating qualities and live throughout the winter in this “subnivean” zone. Once the snow cover has reached a depth of 8 inches or more, the subnivean zone maintains a temperature of close to 32 °F regardless of the temperature above the snow cover.

Diane Kappel-Smith, a Vermont naturalist and writer, describes this as the “winter threshold, and then the underworld begins a time of sheltered calm and darkness.”

The subnivean zone begins to form after the first accumulating snowfall. When snow lands directly on standing vegetation, downed logs and branches, and overhanging rocks, they act as umbrellas, creating protected areas for animals to move about.

Meanwhile, the snow that lands on the ground changes from a solid into a gas without melting, a process called sublimation. Twelve feet down into the soil in a normal snow year, it is warmer in January than in June. The stored solar heat and the geothermal heat rising from the core of the earth is trapped by the snow layer. This heat vaporizes the bottom of the pack, creating delicate, rounded crystals, or “depth hoar.”

In terms of insulation value, light snow is comparable to dry peat, fiberglass, or blown cellulose, because of all the air spaces it contains. If only it wouldn't melt, snow would make a great insulating material for buildings.

Snow Roosting

            Callie and I were snowshoeing in the Frog Lake and Pines State Natural Area over the weekend when my sister-in-law’s young Australian shepherd startled a ruffed grouse out of its snow roost just ten feet off the trail. The grouse exploded from the snow and certainly woke us from any reverie. I know folks who have stepped near a snow-roosting grouse and nearly had a heart attack when the bird burst from the snow beneath their feet.

            Like the small mammals I wrote about in the subnivean zone, grouse learned a long time ago of the insulating value of snow. With their wings and feet, grouse may extend their snow roost up to 10 feet to make a comfy little condo for themselves under the snow.

Common redpolls are known to also roost under the snow. Their tunnels may be more than a foot long and four inches under the insulating snow, says the Cornell Lab of Ornithology.

The Bear Facts

Deane Galloway noted in an earlier column that I stated “The Wisconsin bear population is estimated at 20,400 and has grown on average 3.4% annually since 1988.” I was quoting from a July 2017 Milwaukee Journal article that doesn’t jive with a much higher number – over 28,000 estimated in the fall of 2017 – which is the number currently used by the DNR. I don’t know which one is more accurate, but whatever the number, Wisconsin’s black bears are clearly thriving.

The full moon in January has been called by some the “bear moon” because black bear cubs are typically born in January. Sows now average giving birth to three in a litter, which sounds like a lot of work except for the fact the cubs are tiny, weighing less than a pound each. This makes the cubs smaller relative to their mother’s size than the young of any other placental mammal.

In a month, the cubs will weigh two to three pounds, and will have grown fur almost an inch long. Mother’s milk is their only food, and they get an exceptionally rich formula – 33% milkfat compared to a human mother’s 3%.

It’s cold in the den given that most den entrances are open to the air, so the tiny newborn cubs are kept very close to the mother. When they defecate, she eats the feces to keep the den clean and recycles the unabsorbed nutrients for her own use. 

Two “Wisconsin” Snowy Owls Fitted with Transmitters

            On December 30, a day with a high of 1° and 25 to 30 mile-per-hour winds, a female snowy owl, now nicknamed “Badger,” was caught and fitted with a transmitter near Freedom in Outagamie County.

Then on January 4, two juvenile male snowies were caught just south of the village of Arlington in southern Columbia County. Because like most raptors, snowy owl males are smaller than the females, one of the birds was deemed too small for a transmitter and set free. But the second male, which weighed more than 4 pounds, was an ideal size for a transmitter. Nicknamed “Arlington” for the town, he’s now “on line” and being followed wherever he goes.

While radio-collaring animals is relatively common these days, these aren’t any old run-of-the-mill transmitters. Solar-powered, they record locations in three dimensions (latitude, longitude and altitude) at intervals as short as every 30 seconds, providing exquisite detail on the movements of these birds. Unlike conventional transmitters, which report their data via Argos satellites in orbit, GSM transmitters use the cellular phone network. When the bird is out of range of a cell tower, the transmitters can store up to 100,000 locations, then transmit that information – even years later – when the bird flies within cell coverage. Once the owls migrate north beyond the limit of the Canadian cell phone system, direct contact is lost. However, their transmitters continue to log precise GPS locations, storing them until the owls migrate south the next winter (or the next, or the one after that). This information represents the most detailed record ever made of the movement of owls in the Arctic and subarctic.

The transmitters weigh about as much as seven U.S. quarters, but only 1.5 to 3 percent of the bird’s weight. They’re attached with a backpack harness that goes over the bird’s wings, a method that has not impacted mortality or decreased breeding success.

Previous transmitter data has shown how some snowy owls move out onto the frozen surface of the Great Lakes for weeks or months at a time, apparently hunting for waterfowl using cracks in the wind-driven sheets of ice. The data has also confirmed that snowy owls feed heavily on birds in the winter, especially ducks, geese, grebes and gulls, and for the first time the owls have been documented hunting at night over the open ocean, often using channel markers and buoys as hunting perches.

The researchers have already learned that one of our Wisconsin snowy owls, “Badger,” has remained in a 0.7 square mile area since she was tagged over two weeks ago.

The Natural Resources Foundation of Wisconsin and Wisconsin Public Service Foundation have sponsored two of the transmitters, Madison Audubon Society is sponsoring another, and the Wisconsin Society for Ornithology is funding a fourth.

Sightings

            Denise Fauntleroy sent me a photo of a flying squirrel eating the Christmas popcorn she had strung on a tree outside her window. With a spotlight on the tree at night, she has watched them at length. She didn’t say, however, if they ate the strung cranberries.

photo by Denise Fauntleroy

            Along those lines, Mary, Nancy Burns, and I were snowshoeing on the WinMan trails last week when Mary saw a movement in a tree near the trail. Something was working its way high up the trunk of the tree, and at first Mary thought it was a brown creeper. But it suddenly leapt from the tree and glided to the next tree. Mary hollered for me to catch up to her and as soon as I did, what turned out to be a flying squirrel leapt again into the air and glided away from us toward the ground. This was the first time during the day I had ever seen a flying squirrel in flight!

            We have an entertaining flock of at least 14 pine grosbeaks working our feeders every morning. Besides their beautiful coloration, they also consistently sing, which in the quiet of winter is a very pleasant addition to anyone’s yard.

            This winter continues to bring good numbers of common redpolls and pine siskins to local feeders, but so far few to none of evening grosbeaks, bohemian waxwings, or purple finches.

Celestial Events

            Here’s something to look forward to: January 26 marks the last of the year’s coldest average high temperature: 21°. It’s also the last of the year’s average coldest days. So, everything, on average, should be getting warmer now. Of course, the problem with averages is illustrated well by this quote from Bruce Grossman: “A statistician is a person who lays with his head in an oven and his feet in a deep freeze stating, “On the average, I feel comfortable.”

            We’re up to 9 hours and 31 minutes of daylight on January 27.

            The full blue supermoon occurs on 1/31. To see the total lunar eclipse that same day, you’ll need to be up early at 5:48 a.m. to watch the shadow begin to sweep across the moon from left to right. Totality begins at 6:51, but the oncoming light from the sunrise will diminish the effect.

Thought for the Week

            Nature is party to all our deals and decisions, and she has more votes, a longer memory, and a sterner sense of justice than we do.  – Wendell Berry            

A Northwoods Almanac for 1/5/18

A Northwoods Almanac for 1/5 – 18, 2018  by John Bates

Trumpeter Swan 24Y

A handful of trumpeter swans usually winter-over on the Manitowish River, and this year it appears to be a small family of four: two adults and two cygnets. During the Manitowish Waters Christmas Bird Count on 12/16, Mark Westphal took a picture of this group just below Benson Lake, and one of the adult swans was banded #24Y. I contacted the DNR to get the backstory on this bird and learned that 24Y was banded as a cygnet on 9/6/2007 in Price County, so it’s 10 years old.

photo by Mark Westphal

It’s unclear what 24Y’s gender might be – males are somewhat larger and heavier than females, but otherwise look exactly alike (the only way to be certain is to examine the bird’s vent, which is not exactly an option). It’s also unknown if 24Y has been a successful parent up to now, but trumpeters often begin breeding at the age of three, so the two cygnets could be 24Y’s seventh brood. Trumpeters usually mate for life, and they’re long-lived – 20 to 30 years in the wild. So, 24Y may have another ten or more years of parenting ahead of him or her. Currently, trumpeter swan #82K, banded in Wisconsin, is the oldest banded swan in North America, and is now 27 years old.

Trumpeters are the largest native North American waterfowl, weighing between 21 and 30 pounds and with a winspan over seven feet. Thus, they need a lot to eat during the winter, and I’m always impressed that they can find enough food on the few open sections of the Manitowish River. They eat a wide assortment of aquatic vegetation (arrowheads, pondweeds, sedges, pickerelweed, rushes, smartweed, cattails, bulrushes, milfoils, wild celery, wild rice, algae – you name it). But given that most aquatic plants die-back in the fall, the swans likely survive mostly on tubers that they dig up from the sediments.

The literature says a thick layer of down protects them in subzero temperatures, but as a human, I find it almost unimaginable that anything can stay warm swimming around in -20 degree temperatures.

Few birds exhibit the grace and beauty of a trumpeter swan, and what a gift that they share their beauty with us all winter!

Latest Update on Snowy Owl Irruption

According to Ryan Brady, bird monitoring coordinator for the DNR, as of 12/26 “approximately 202 individual snowy owls (give or take a bunch) have been detected, which far exceeds those found in 2016-17 or '15-16, but is in line with the 210 and 156 found by this date in 2014-15 and 2013-14, respectively. Only 11 of our 72 counties lack reports this year . . . the influx of incoming birds does appear to be slowing somewhat, as might be expected this time of year. Juveniles still dominate, although several apparent adult males were photographed as well in recent weeks. Finally, vehicle collisions remain a significant source of mortality, for many of these birds are inexperienced hunters and unfamiliar with a developed landscape.”

It appears it’s not hunger that produces these mega-flights, but the opposite – an amazing abundance of summer food. Large populations of lemmings, voles, ptarmigan and other prey during the summer breeding season led to large clutches of owl eggs and excellent survival of the chicks. But once winter came and prey numbers dwindled, the young had no choice but to migrate south – too many mouths for too little food.

Sightings – Pine Grosbeaks, Northern Shrikes

A few days before Christmas, Paul Strong in Hazelhurst reported seeing both a juvenile and an adult shrike chasing birds at his feeders. A week later Paul also observed a hoary redpoll in a mixed flock of common redpolls and pine siskins. 

Mary and I have 12 pine grosbeaks visiting our feeders as of 1/1/18. These exceptionally pretty and vocal birds are circumboreal, nesting and usually wintering in subarctic and boreal forests from Siberia in eastern Asia to Scandinavia and, in North America, from eastern Canada to western Alaska. They migrate south only in winters triggered by limitations in their foods. We didn’t see any the last two years at our feeders, but now every morning, we’re treated to breakfast with a flock of pine grosbeaks as companions.

pine grosbeak range map

They eat our sunflower seeds, but we’ve watched them many times eating crabapples and highbush cranberries, too. In wilder winter circumstances than our back yard, they feed primarily on a variety of buds and the seeds of mountain ash, box elder, and ash.

            Their short and heavy conical bills allow them to nip off buds and the growing tips of conifer branches, and to crush seeds.

male pine grosbeak photo by author

female pine grosbeak photo by author

Blue Moons

This year, January offers us two full moons, one that already occurred on 1/1 and the other on 1/31. Given that full moons occur every 29.5 days, February won’t have a full moon, but will be followed in March by two full moons on the 1^st and 31^st.

The last time two blue moons happened in the same year was 1999, an event that occurs every 19 years (remember to look for them in 2037)!

January's blue moon on the 31st will also feature a total lunar eclipse, the only lunar or solar eclipse over Wisconsin this year. Northwoods viewers will be able to see it early in the morning very low in the western sky. The eclipse will start at 5:48 a.m. and totality will begin at 6:51. Unfortunately, moonset and sunrise occur only 33 minutes later, so much of the eclipse will be washed out in the morning light.

Also of note, both of the January full moons are “supermoons,” appearing about 7% bigger than normal. And because the moon will turn a reddish-orange color, a total lunar eclipse is often called a blood moon. So, it will be a full blue supermoon eclipse.

The “blue” in a blue moon comes to us from over 400 years ago when the phrase “once in a blue moon” was said to indicate how rare an event might be. But in 1883, the moon did appear blue when the Indonesian volcano Krakatoa exploded and its dust turned sunsets green and the moon blue all around the world for nearly two years. And in 1951, huge fires in western Canada billowed out so much smoke that the moon turned bluish in northeastern America.

So, a blue moon indicates something rare in general, and something specifically rare astronomically. But it also has come to mean the second full moon in a month, the apparent result of an obscure article in Sky and Telescope magazine in 1946 and then an NPR program in 1980 where that article was read aloud. So, the term is part folklore, part historical fact, and part just something that has caught on through media use.

Radiative Balance

Why isn’t the coldest day of the year on winter solstice when we have the least amount of light? And why do average winter temperatures continue to fall until late January? Well, it’s all about the earth’s energy balance. So far this winter, the earth has been radiating more energy back into space each day than it receives from the sun, so we’re still losing heat and getting colder. This is because over the course of the year, the earth’s land surfaces, oceans, and atmosphere absorbed an immense amount of energy which is still being radiated back to space.         We’ll continue radiating out more heat than we receive until late January when the “radiative balance” will be reached, and we then begin receiving more energy than we lose. Temperatures, on average, then will slowly begin to rise.

Quaking Aspen – Winter PHS       

Quaking aspens are the most common trees in the Northern Highlands area, but they also grow out west at elevations as high as 10,000 feet and thrive in cooler climates far to our north. Like other true cold weather species, quaking aspen (or “popple”) has evolved ways to adapt to intense winter conditions, including an ability to photosynthesize through its inner bark. In winter, when other deciduous trees are mostly dormant, quaking aspens can keep producing sugars. Trees growing in more northern latitudes tend to have greener bark with higher chlorophyll levels, a character of quaking aspens, as an adaptation to cold winter temperatures.  

quaking aspen range map

            Most northern trees are conifers, holding tight onto their leaves (needles in this case) as a means of withstanding long winters and short summers. Quaking aspens are one of the very few deciduous trees to thrive in the otherwise mainly evergreen northern environment, and it’s thought that their ability to photosynthesize through their bark accounts in part for their ability to compete.

Celestial Events

            If you’re looking for planets in January, you have to get up before dawn – none are visible at the easier viewing time after sunset. Mars, Jupiter, and Saturn are all visible in the east-southeast before first light. On 1/6, look before sunrise for Mars just below Jupiter. Before dawn on 1/11, look for both Jupiter and Mars to be four degrees south of the waning crescent moon. And also before dawn on 1/15, Saturn will be two degrees south of the crescent moon.

            On 1/8, the sun rises one minute earlier for the first time since June 10, 2017. And by 1/13, we’ll reach 9 hours of daylight – now our days are growing longer by two minutes every day. New moon on 1/16.

Thought for the Week

“Winter comes a shimmer of hoarfrost, a mist of snowflakes from a scudding cloud a roaring wind with a barbed-wire edge. It comes as a fragile film of ice needles on the pasture pond or woodland brook. It comes in the brittle cold silence of night, the sun-dazzle or sullen overcast of day, echo of those ages when ice locked up the northern hemisphere 10,000 years at a time, reminder that the long cold and the deep ice can come again . . . And yet winter blankets the tender root and bulb, relaxes the fevered urgency of growth and fruition, brings rest and renewal, provides a time for summaries. It is the essential pause in the throbbing of the great, eternal rhythms of life.” Hal Borland, Seasons

Please share your outdoor sightings and thoughts: call 715-476-2828, e-mail at manitowish@centurytel.net, snail-mail at 4245N State Highway 47, Mercer, WI, or see my blog at www.manitowishriver.blogspot.com.