A Northwoods Almanac for March 5 – 18, 2010
Water Levels
With spring snowmelt only a little over a month away, the question foremost on many people’s minds is what will our area lake levels look like? The drought we’ve experienced over the last 5 years has taken a huge toll. Biologist David Schmoller from Minocqua kindly sent me the following precipitation data that was taken over the last decade at the Minocqua Dam (average precipitation for our area is 32.1 inches per year):
Year Precipitation Difference
2000 32.56 inches +0.46 inches
2001 34.07 +1.97
2002 38.00 +5.90
2003 27.26 -4.84
2004 32.03 -0.07
2005 30.79 -1.31
2006 26.88 -5.22
2007 28.97 -3.13
2008 25.32 -6.78
2009 17.54 -14.56
Note that the last year we received more precipitation than the average was 2002. In 2004, we received the average precipitation, but it’s been downhill since then. Since 2003, our area is down 35.91 inches from normal, which has created exceedingly low water levels in many lakes across northern Wisconsin.
The shortage of precipitation isn’t the whole story, however. Our lake levels have also declined due to shorter winter ice-duration and increased average annual temperatures this decade, which have resulted in increased evaporation from our lakes and increased transpiration from plants.
I asked Tim Kratz, director of the UW Trout Lake Limnology Station, to comment on the scientific data that pertained to local historical water levels. He wrote, “The USGS has water levels data for Anvil Lake (just east of Eagle River) going back to the late 1930s. It shows that the current water level in Anvil Lake is lower now than at any other time since the record started. The Wisconsin Valley Improvement Corporation has water level data for Buffalo Lake (off Hwy J between St. Germain and Minocqua) from the early 1940s to the early 1990s. We have data from Crystal Lake from 1981 to the present. When we compare the overlapping period of record between Crystal Lake and Buffalo Lake and then use that relationship either to predict earlier Crystal Lake water levels or post 1990s Buffalo Lake water levels we also conclude that water levels now are lower than any other time in the historical record.”
One of the major ecological issues we face as shorelines retreat due to lower water levels, is that the shoreland branches and logs that fell into these shallow waters over many decades are left high and dry. Numerous research studies have conclusively shown that this coarse woody habitat along shorelines is essential habitat for everything from fish to frogs, and that as coarse woody habitat decreases so does the growth rate and reproductive success of fish and other organisms.
To reverse this trend, we need snow now and rain in a month, and lots and lots of both. Our current moderate snow depth is of significant concern because it will translate into only a minor pulse of spring meltwater. While most of us start begging for the snow to go away in March, in truth we need some major snow storms between now and April if we wish to have a good recharge of our rivers and lakes from the spring thaw. And then we’ll need spring rains of Noah-like proportions to refill our groundwater and wetlands, which provide the slow and steady release of water to our rivers and lakes throughout the summer.
March as Armageddon
“Winter is a predictable kind of Armageddon,” wrote naturalist Diane Kappel-Smith. While Kappel-Smith referred to the entire season, I think she had March in mind as the most predictable time for Armageddon to occur. It’s March when the accumulated stressors of five months of cold, snow, and ice weigh most heavily on animals. It’s March when hunger and weakness arrive at their peaks. It’s March when life often hangs by a thread and extreme weather can push an animal beyond its endurance. And I’ll bet it was March when someone coined the old adage of “the straw that broke the camel’s back,” because March is the final straw.
Take wintering deer, for example. White-tailed deer employ every trick they know to conserve enough energy to make it to March. At night, they conserve heat, and thus energy, by curling up in sheltered beds under conifers that slow skyward radiation and inhibit wind. In deep snow, they winter in “yards” where they can share a network of tramped trails and conserve more energy. They stand on their rear legs to feed on tree branches seven feet above the ground, creating browse lines easily observable in particular around lakeshores. They change their diet of woody browse, eating five or more pounds a day of buds and twigs of plants that aren’t all that nutritious, but are what’s available. And they slow down their natural metabolic rate to a point which one ecologist describes as “a walking hibernation” that reduces by 30 percent their need for food.
Nevertheless, they slowly starve over the winter, typically losing a minimum of 15 percent of their body weight in the best of circumstances, and 20 to 25 percent in poorer habitats. When their weight loss reaches 30 percent, they’re near the cliff edge of dying from exposure and starvation.
It’s March when that cliff draws near. And even if survival is granted, a malnourished doe may lose her fetuses, or produce only one fawn, which though alive may be born underdeveloped and then be poorly nourished by the starving mother.
So, while cabin fever descends in March on the human population in the Northwoods, a different sort of fever takes hold of much of the animal world. It’s make or break time, where an intense cold spell or heavy snowstorm can mean everything. To date, our winter has been very mild in terms of low temperatures and average depth of snow, which bodes well. But there’s more winter to come, and the quality, quantity, and duration of late winter snow and cold will make all the difference.
Sightings
On 2/28, Cherie Smith in Lake Tomahawk reported watching two pine siskins “carefully selecting the dog hair I threw outside after brushing. One supervised while the other one looked for just the right hair!” She wondered if they might be building nests already. I checked the Atlas of Breeding Birds of Wisconsin, which said, “During April and May following a greater than normal winter presence, isolated pairs of siskins in central Wisconsin will engage in breeding activities that include courtship, copulation, and nest building. However, these birds have no intention of remaining to raise young, but instead, and almost without exception, leave the area entirely.”
Now it’s always possible that these siskins didn’t read the literature about their behavior, and have chosen to breed anyway. But it would seem very unlikely, particularly in February.
On 2/22, Barry Dalberto in St. Germain reported hearing “the remarkable sound of ‘trumpeting’ sounds, low and melodious. Then I looked up and saw 5 black beaked trumpeter swans flying just above tree level.”
More than likely these were local over-wintering trumpeter swans simply moving about to find the best open-water feeding sites. There’s a family of trumpeters over-wintering this year on the Manitowish River, as they have for numerous years. I don’t know of a wintering trumpeters in the St. Germain area, but that would be most likely.
On 2/22, Rolf Ethun reported seeing a small flock of evening grosbeaks. “I was lucky enough to have a small flock of at least a dozen at my feeder about 7:30 this morning. In ten minutes they were gone.”
Mary & Mark Pflieger in Harshaw sent me a photo of a barred owl they’ve been watching feeding on their suet all winter, which is really quite uncommon. Sometimes barred owls come in to feeders in late winter, apparently out of great hunger, but it’s very unusual for an owl to utilize a feeder all winter.
And for the most unexpected observation of February, on 2/21, attendees at a birding trip of the Horicon Marsh Bird Club watched a pair of common loons on the Beaver Dam river where it flows under the Meadow Road bridge south of Leipsig. Early spring migrants are often observed on southern Wisconsin lakes by mid-March, but loons in February are exceptionally early.
Golden Eagle Attacks White-tailed Deer
A recent posting on the Wisconsin BirdNet showed a series of photos taken of a golden eagle attacking a white-tailed deer at the Nachusa Grassland in Lee County, Illinois (see http://www.ilbirds.com/index.php?topic=32809.msg41222#msg41222). Given the number of ruses that come over the Internet, some questioned whether a golden eagle would really attack a deer. Tom Erdman, curator of the Richter Natural History Museum at UW Green Bay, wrote in response that adult golden eagles in the West “kill mule deer and some mountain goats . . . Typically they hit the hind-quarter, rump, first and then when the animal swings around to respond, the second foot hits the head, and the first foot moves up to the neck. At 500 lbs pressure per/square inch at the tip of the talons, it can be quick.”
He added, “Golden Eagles have been used to hunt fox, coyotes and wolves for 100s of years by falconers.”
Celestial Events
Our average high temperature reaches 32°F on 3/6. By 3/8, we are blessed with 11.5 hours of sunlight. New moon takes place on 3/15.
In March, the only planet visible at dawn is Jupiter, low in the southeast. However, after dusk, Venus is brilliant low in the west, Mars is high in the southeast, and Saturn rises in the east.
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