A Northwoods Almanac for 8/19 – 9/1, 2016
I’ve received a number of calls and emails recently asking about the syrupy smell emanating from some local woodlands, and like last summer, the culprit appears to be honeydew. You may recall that honeydew is the alias for the sticky, misty excretions made by Lecanium scale insects that feed on sap in the tree leaves. The insects take in much more sap than they can hold, and then exude the excess, the dew falling onto leaves, decks, cars, etc.
|photo by Bev Wigney|
Linda Williams, forest health specialist for the WDNR – Northeast Region, found that the scales causing the problem are European Fruit Lecanium (Parthenolecanium corni). She noted in her June Forest Health Update, “Although this pest has been previously identified in Wisconsin in the early 1900’s, this may be the first largescale outbreak of this pest in a forest setting in Wisconsin . . . Host trees that I’ve found scales on include: Oak, cherry, ash, maple, dogwood, musclewood, basswood, and hazel brush . . . Homeowners may want to rinse off the honeydew from outdoor items on a regular basis as the stickiness can be unpleasant and can allow sooty mold to grow.”
The Lecanium scale is native and is usually controlled by ladybug larvae, as well as tiny parasitic wasps and fungal diseases. Obviously, enough Lecanium scale survived this summer to again create a sticky mess. Next summer, however, given the effectiveness of the scale insect predators, the woods hopefully will no longer smell like the local Waffle House.
Forest Tent Caterpillars – Wither Art Thou?
On the other end of the abundance coin is the lack of forest tent caterpillars. You may remember the last big outbreaks occurring in 2001 and 2002 when literally billions of the leaf-eating caterpillars defoliated trees on millions of acres of forest lands, the largest outbreaks in forest history. At their peak infestation, there were up to 4 million caterpillars per acre. Folks cancelled vacations, cancelled outdoor events, and were generally going over various psychological edges. The more rabid even accused the DNR of dropping the caterpillars at night from black helicopters, a story concocted for reasons only known to those who suffer such delusions.
Then the native parasitic “friendly flies” appeared, landing on everything and everyone, but also decimating the caterpillars’ pupae.
We also learned then that forest tent caterpillars explode cyclically every 10 to 15 years.
Out of sight, out of mind is how most of us live, so only a few people have since commented on their absence. Doing the math, they should have reappeared by now. However, so far, they’ve been a bust. In Minnesota (I’m unable to find Wisconsin data), significant numbers did occur in 2013, but their numbers crashed in 2014, while in 2015 they were barely noticeable. And this year they are being found only in isolated pockets. Perhaps we’ve dodged the forest tent caterpillar bullet, but let’s give it another year or two before we breathe a sigh of relief.
Sightings – Harrier Prey Exchange, Juvenile Eagle, Purple Finches, Migration
Mary, Callie, and I were walking one of the dikes at Powell Marsh when a male northern harrier flew in front of us dangling a mouse or vole from its talons. I kept him in my binoculars as he flew far beyond where we stood, and then noticed another harrier flying up from the ground towards him. The male dropped his prey before the other harrier got to him, and the one below caught it and flew back down to the ground. Harriers are known for their in-flight prey exchanges, and this was only the second time in my life I was able to watch an exchange occur.
Wil Conway was fishing a few weeks ago and observed a vocal juvenile eagle flying from shore-station to shore-station. Wil’s a fine photographer and was able to get many close-up shots of the eagle which he was kind enough to share with me.
|photo by Will Conway|
At last count, we have at least 25 juvenile purple finches visiting our feeders, as well as young rose-breasted grosbeaks, red-breasted nuthatches, white-breasted nuthatches, and red-winged blackbirds. They are currently eating all of our ripening elderberries, so again, we’ll be out our elderberry jam. But it’s a small price to pay for the pleasure of so many birds in our yard.
Warbler migration has begun. Sarah Krembs sent me a fine photo of a juvenile chestnut-sided warbler that may already have been on the move.
|photo by Sarah Krembs|
A Bevy of Bitterns
Sarah Krembs observed six American bitterns at one time in her binoculars, which given the cryptic coloring and secretive behavior of bitterns, must be a record. She was birding on Powell Marsh and noted that in previous years, bitterns have been difficult to visually find, though she could often hear them.
|photo by Sarah Krembs|
I’m not sure if I’ve ever seen more than two at a time in my binocs, so Sarah is way ahead of me. She was puzzled, however, by this abundance of bitterns and wondered if this was a particularly good year for some reason. Frankly, I have no idea. Cornell’s “The Birds of North America,” my Bible on such matters, has this to say in general about bitterns: “Remarkably little is known about the biology of this species.” So, at least I’m in good company.
The few research studies that have been done relate that the average clutch size is 3 to 5 eggs, all incubated and raised by the female. Most nests are placed among dense emergent vegetation over very shallow water and are very well hidden. As for abundance, one study on a large marsh in Wisconsin found 40 calling males per 100 hectares (247 acres). The eggs are incubated for 24 to 28 days, and the young are altricial (born immobile, featherless, and generally helpless), covered with yellowish olive down. The chicks are given regurgitated, partly digested fish, frogs, snakes, crayfish, and mice, and supposedly are able to leave nest when one to two weeks old, but then linger near the nest for up to a month while being fed by the adults. Their age at fledging is unknown, and all association between family members is said to end after fledging.
So, Sarah’s six bitterns aren’t likely to have been family members, but rather six adults foraging in a relatively small area. They’ll migrate sometime in September or October, but that too is unknown about them.
In northern Wisconsin, snapping turtles, painted turtles, and state-threatened wood turtles emerge from lakes and rivers in mid-June to lay their eggs wherever they can find loose soil, sand, or gravel. The eggs incubate for anywhere from 55 to 120 days, if they aren’t dug up by the host of predators that voraciously await them. Earliest hatches occur in August if the summer has been hot and dry, while later hatches occur in September if it’s been cool and wet. A hatch in August usually means a much higher percentage of females, a hatch in September means far more males. If the summer has been particularly cool and wet, the hatchlings may even remain in the nest over the winter and emerge the following spring.
Today’s snapping turtles have hardly changed from 215 million years ago when the most primitive turtles lived. Says one researcher, these are “creatures who are entitled to regard the brontosaur and mastodon as brief zoological fads.”
Snapping turtles can live a very long time. It’s possible to determine from the rings on the shell how old a snapping turtle is. The oldest observed age for snapping turtles so far is 75 years, though its believed they can live more than a century.
The semi-terrestrial wood turtle prefers clean rivers and streams with fast flows and healthy adjacent wetlands and upland deciduous forests.
Nighthawk migration peaks in later August when occasionally thousands can be seen in one evening. The largest flight ever recorded in the Upper Midwest was 43,690 nighthawks tallied in three hours on August 26, 1990, in Duluth, Minnesota!
Nighthawks leave northern Wisconsin early, because they require a constant supply of flying insects. They have little choice but to stay at least one step ahead of the first killing frost, which in the North often comes in August.
In migration, individuals follow no apparent leader, flying close to the ground, their wings often beating in unison. The great distance they travel to their winter range in southern South America makes their flight one of the longest migration routes traveled by any North American bird.
In many ways, the name “nighthawk” is inappropriate for this bird because it is most active at dawn and dusk, not night, and like other members of the nightjar family, it’s not related to the hawks.
Look for nighthawks close to evening, flying over open fields, near airports, and along highways. The fly erratically as they try to capture insects on the wing, twisting and turning in a bat-like flight pattern. Their pointed, angular wings, each with a broad white line, help to quickly identify them.
“August is tomatoes ripening and the insistent note of the cicada punctuating the heat of midafternoon. August is . . . the stain of blackberry juice on the fingers. August is a languid river and a springhouse brook reduced to a trickle. August is . . . the first sprays of goldenrod in the uncut fencerow. August is baby rabbits almost grown, and pilfering in the garden; it is fledglings all feathered and on the wing. August is . . . wild grapes festooned on the trees at the riverbank; it is the algae on the pond and the fat green thumbs of cattails in the swamp, and ironweed purpling, and vervain in full bloom. August is a hastening sun, earlier to bed and later to rise. August is Summer thinking of the cut and color of her Autumn costume.” Hal Borland, Sundial of the Seasons
A solar eclipse will occur on 8/21, reaching its maximum around 1:15 pm central time, but we’ll only see about 40% of it. Folks further south and out West will be able to see it in its totality.
Please share your outdoor sightings and thoughts: call 715-476-2828, e-mail at email@example.com, or snail-mail at 4245N Hwy. 47, Mercer, WI.