A Northwoods Almanac for June 22 – July 5, 2012
Turtles Laying Eggs
Mary and I observed both painted and snapping turtles laying eggs as of June 7th, which seems a week or so early for our area.
Here’s a quick snapshot of the spring-to-fall lifecycle of a snapper:
Snapping turtles in our latitude typically emerge from hibernation in early May when the water is about 41 to 50° F. They initially bask while moving around some, but don’t eat until the water reaches about 60° F. The females soon undertake nesting migrations in search for a preferably sandy, sunny nest site. Interestingly, the males also migrate and aggregate in areas close to major nesting sites and on migration bottlenecks in order to intercept the females and mate. Ideally, the females will locate their nests close to small streams, where the hatchlings will then spend their first couple of years before they move into larger bodies of water.
Females may migrate long distances, 2 to 8 miles through lakes and rivers, to find ideal spots. By turtle standards, the migrating individuals often move relatively fast – the mean speed of travel can be up to 1 mile per day.
When the female reaches her desired site, she digs a nest chamber, a task that will take her about an hour and a half, and then she will lay from 22 to 62 one-inch diameter eggs. Once her eggs are laid, she will fill the nest hole again with sand, press it down, try to camouflage the nest, and leave. Unfortunately, up to 90% of the nests will be destroyed by predators like raccoons, skunks, foxes, and mink, often almost immediately.
The eggs hatch after 60 to 120 days, usually in September in this area. Cold temperatures in our area constrain embryonic development. Snappers have temperature dependent sex determination, which means that the sex of the turtle depends on the temperature at which the egg was incubated – males like it colder, females warmer.
The hatchlings will dig out of the nest and somehow know to head straight for the nearest water, even if they cannot see it. If the weather is too cold after hatching, the hatchlings may sometimes try to overwinter in the nest.
Today’s snapping turtles have hardly changed from 215 million years ago when the most primitive turtles lived. In comparison, the age of the dinosaurs was approximately 150 million years ago, 65 million years later than the first turtles. To put things into further proportion: humans are estimated to have evolved a mere 3.5 million years ago.
Abundance of Butterflies and Moths
Numerous people have told me they are seeing unusually high numbers of butterflies and moths, and have wondered why. I asked Phil Pellitteri at the UW Madison Insect Diagnostic Lab for his interpretation, and his very short and straightforward reply was this: “Lots blew in from down south with all the strong southerly winds. Mild winter helped our natives. Dry weather is good for caterpillars.”
Hannah Dana on Mercer Lake sent me fine photos of three moths: a luna moth (Actias luna), a big poplar sphinx moth (Pachysphinx nodesta), and a one-eyed sphinx moth (Smerinthus cerisyi).
6/7: Mary and I saw a pair of trumpeter swans with 6 chicks on the Little Turtle Flowage near Mercer.
6/7: Hannah Dana wrote: “My cousin, Dr. Tom Petersen and his wife, Sharon, live on Mercer Lake. A couple of weeks ago they were looking out the window overlooking the lake shore and saw a mother Canada goose with her brood. They noticed that the last gosling in the queue was stumbling and lagging behind. Then they realized something was wrong, and Tom went to the lakeshore to see what was going on. The little one was wrapped in gobs of fishing line that some idiot had thrown in the water rather than keep in the boat to dispose of later. The mother and the siblings swam farther around the bay and didn't seem to realize the last in line was in trouble. Tom picked up the gosling and took it into the house. Tom, a dentist, used tweezers to lift the knots and Sharon, a nurse, used a tiny scissors to cut the line. Finally, the baby (who had remained calm) was free of its imprisonment, and Tom returned it to the water. Lo and behold, Mom and the crew turned around and swam back to it, encircled it and murmured as if to say, "Welcome back. Are you okay? What was it like in that People House?" Then, they went on their way around the point to the next bay.
“Years ago, I would visit my friend, Marge Gibson, who runs the Raptor Education Center in Antigo. So many eagles, loons, swans and other creatures would be ensnared by line discarded by fishermen. She was able to save many of them, but some died from starvation, drowning, dehydration etc. I find no excuse for "sportsmen" being too lazy to take their old line home, preferring to throw it into the water. Surely, they must be able to foresee what could happen to the birds and animals that get caught up in it.”
6/10: Joe Mastalski reported seeing a loon chick on Lake Kaubashine in Hazelhurst.
As a related note, in a current study of 10 loon nests on the Turtle-Flambeau Flowage, nearly all the eggs were laid from May 10 to 17. Since loons employ a 28-day incubation period, those eggs that weren’t predated or flooded out nearly all hatched in the window from June 10 to 17, as should be the general case for loon nests throughout our area.
6/12: Pat Schwai on Cochran Lake wrote: “When I was a child, my family camped at Twin Lakes campground in Price County, just a short distance from our present home. The call of the whip-poor-wills was a nightly event. But since arriving here in 1996, we've seldom heard them, and then only at a distance. This year we heard our first whip-poor-will on May 30. It has progressively been calling closer to our house, which is not quite as delightful at 4 a.m. Nevertheless, we feel very fortunate to hear him nearly every evening because whip-poor-wills seem to be rare. Are they?”
I wouldn’t say rare, but whip-poor-wills are certainly uncommon. Breeding birds appear to strongly prefer very open, dry woodlands since most of their feeding is done in open spaces at night. In areas where brush has grown up in the understory, where moths have declined due to the use of pesticides, and where predators like raccoons have increased, whip-poor-wills have correspondingly decreased.
6/14: Pete Dring observed large leaf aster in bloom, which is extremely early for this plant to be flowering – it usually blooms around mid-July.
Celestial Events – Summer Solstice
Summer solstice is widely recognized as the beginning of summer in the Northern Hemisphere and the beginning of winter in the Southern Hemisphere. The solstice represents a “turning” of the year – the sun is now rising and setting as far north as it ever does.
However, for people living around 40° north latitude, the latest sunsets of the year happen in late June (at our latitude of 46°, the latest sunset of the year comes on or near July 1 every year). And conversely, in the Southern Hemisphere at 40°south latitude, it’s the year’s latest sunrises that happen around this time of year despite the fact that the longest (or shortest) day of the year falls on the June 20 solstice.
Several weeks ago when Mary and I were hiking in far northwestern Scotland in an area around 58° latitude, it seemed like it never got dark. We’d go to bed around 11 p.m. and though we’d get up now and again during the night, we never were up at a time when it was actually fully dark.
For perspective, we live in Manitowish at about 46.1° north latitude. Each degree of latitude represents 69 miles further north, so at our cottage in Poolewe, Scotland, we were over 800 miles north of Manitowish. For comparison sake, head 800 miles north from the Lakeland area and you’ll find yourself in uninhabited, roadless areas of northern Ontario, or further east, you’d be swimming in the middle of Hudson’s Bay.
People can, however, live just fine in far northwestern Scotland, because the Gulf Stream brings warm ocean water along the coast which moderates the climate. Because of those warm Atlantic currents from the Caribbean, the coldest winter temperature ever measured in Poolewe was 14°F in 1986, while temperatures are rarely very hot in summer; the highest temperature recorded was 84°F in June 1978.
The Gulf Stream is such a remarkable moderating factor that in Poolewe you can visit Inverewe Gardens, a 50-acre, world-renowned garden that is an oasis of exotic plants – rhododendrons from the Himalayas, eucalypts from Tasmania, olearia from New Zealand, and other species from such far-flung places as Chile and South Africa.
The garden was created in 1862 by Osgood Mackenzie on a 850 hectares (2,100 acres) estate bought for him by his mother. When he placed rabbit and deer fencing around the headland in Loch Ewe in 1862, there was just one tree, a three-foot-high dwarf willow, within the boundaries he had selected. Since the west coast of Scotland is susceptible to strong winds and salt spray, one of the first things Osgood did was establish shelterbelts of pines. He reclaimed the seashore with good soil reputed to have been brought by the basketful from Ireland, and by the end of the century he had established one of the finest collections in Scotland of temperate plants from both Northern and Southern hemispheres.
Which all just goes to show what determination, imagination, and no small amount of money can achieve. And as a result, visitor numbers now approach 100,000 per year.
Fireworks and Birds
As July 4th approaches, I’m obliged to simply remind folks that many birds are still nesting or are raising their young. Since fireworks and nesting birds don’t coexist well, please consider which you prefer more.