A Northwoods Almanac for June 14 – 27, 2019 by John Bates
Monarch Sun Compasses and Time Antennas
Monarch butterflies have reappeared in northern Wisconsin as of the beginning of June – I saw my first one on 6/6. To me, their return is nothing short of miraculous because as monarchs have slowly migrated their way north, several generations of monarchs have already lived, laid eggs, and died this year in North America.
The first generation were those that wintered in the 10,000-foot-high Mexican mountains, and then migrated in the second week of March into the southern U.S. They’re called “super-generational monarchs” by ecologists, by which they mean they’re very different physiologically from all other monarchs. They’re bigger, they can live for many months, they can’t reproduce initially, and they can fly all the way to the Mexican mountains in the autumn, up to 3,000 miles.
What also makes these monarchs super-generational and very different from the generations before them is that they make less of one special hormone, a hormone that in its absence prevents them from aging, allowing them to live 8 times longer than other generations of monarchs. The typical adult monarch, the non-super-generational, only lives 2 to 6 weeks.
Thus, the super-generational monarchs are able to fly all the way to Mexico, winter-over, and then return to North America. These individuals are the same species of monarch, but they have a totally different life span. It would be like some of us being able to live for 400 years.
What also makes their migration back to the U.S. miraculous is that they have a brain the size of a sesame seed, but this brain guides them to go to a place they have never been before and then to specific trees in the Mexican mountains, and then back to North America. How do they know where to stop, for instance, in the Mexican forest? No one knows.
But scientists have figured out how they navigate. They have two internal clocks: a circannual clock, which keeps track of annual cycles like when to migrate, and a solar compass-clock that tells time, which is the key to their navigation.
Consider that they have no map – they only have a heading to follow. Their solar compass can read the horizontal position of the sun, but the sun moves from east to west throughout the day. If it’s mid-morning, the sun will be on their left if heading southwest. If it’s mid-afternoon, the sun will be on their right.
So, they have to know what time it is via the position of the sun, and after years of research, scientists have learned it’s the monarch’s antennae that can somehow convert the sun’s position into “telling time.” They then do some fancy internal math and set their compass on the right heading. And if it’s cloudy? Special cells in their eyes can find the sun on cloudy days using polarized light.
Once in Mexico, they live off stored energy all winter, and then something changes. The hormone that stopped them from aging increases, and they become reproductively active again.
Now they need to reverse their internal compass heading and fly back north. Somehow their compass reverses itself, and in a few weeks, they arrive in the southern U.S., where these adults lay eggs and die. A new generation then hatches out, flies part or all of the way north, lays eggs and dies. Once here, summer monarchs live only three to five weeks compared with eight or nine months for the overwintering adults.And when the autumn arrives, the 5thgeneration, the super-generational, leaves for Mexico.
It certainly seems like magic, but these skills have been written in their genetic code and passed down through literally millions of generations.
So, when you see that first monarch this June, say a particularly reverential hello, because that monarch has never been to Wisconsin before and its eggs will likely be the source of the annual super-generation that will depart in the early fall for Mexico once again.
Sightings: Lewis’s Woodpecker, Northern Mockingbird, Blackburnian Warbler, Eagle/Heron Attack
There’s tons going on! Here’s a sampling of sightings I’ve had or that were sent to me:
5/28: Sue Conley and Michael Stieghorstobserved four pairs of scarlet tanagers while kayaking on White Sand Lake in Lac du Flambeau: “They were moving about at all levels of pine, poplars and cedars (mostly about 2/3rds of the way up) on the east shoreline. Three males were brilliant red and the fourth even brighter orange . . . Several dull yellow/green females were present . . . and no obvious bonding activity between pairs nor competition among any of them, nor other birds . . . it was so vibrantly, brilliantly, memorably vivid as we watched for about 20 minutes!”
5/29: Mic and Nancy Austin, who live a few miles west of Hazelhurst, sent me photos of a Lewis’s woodpecker that had been at their feeders for two days. Named after Meriwether Lewis who first described one on the Lewis and Clark expedition in 1805, Lewis’s woodpeckers are a far western species that nest eastward only as far as Colorado. In Wisconsin, there’s only been five sightings of this species since recordkeeping began in the late 1800s, so this was a big deal! Unfortunately, the bird departed before anyone else could get to see it, but please keep your eyes peeled for this species if you live around Hazelhurst, because it may still be in the area.
5/31: Caroline Sedlak sent me photos of a red-headed woodpecker that was exploring their yard in Minocqua. She noted, “We have lived here since 2010 and this is the first time we have seen one.” They are quite uncommon, so it’s a coup to have one in your yard.
6/5: Sondra Katzen and Dave Derk were in Presque Isle getting ready to go out fishing in the early evening and witnessed the following: “We were on the pier when we heard a lot of bird distress calls coming from the middle of the lake in more than 40 feet of water and about 150 yards from shore. Crows and ravens were flying from all directions to see what was going on. We quickly jumped in the boat and headed to the commotion, thinking an eagle had injured a loon. When we got to the scene, we came upon an adult eagle in the water holding onto an adult great blue heron, who was also in the water. And about 10 feet from the eagle and heron was a pair of loons. We believe the eagle had the heron in its talons and was attempting to pull it to shore . . .
“As we approached, the crows and ravens flew away, and the eagle lifted itself out of the water and flew away. The two loons stayed nearby just watching the entire scene unfold, and probably grateful they weren’t the ones being preyed upon. The heron was obviously in distress and weak from flapping its wings trying to fly out of the cold water. Having a lot of animal experience, Dave grabbed the heron at the neck and its legs and assessed it to see if it had any injuries. The heron looked in good condition, but was weak. When we reached the shoreline, Dave carefully placed the heron down, where it walked along the shore.
“The next day we went back to the location where we released the bird to check and see if it was still there. We did not see it and took that as a good sign that the heron recovered from its ordeal with the eagle. Over the next two days, we also threw a few walleyes to the eagles (they have a nest on the lake) to make up for rescuing the heron.
“Several days before that we were fishing for perch in a shallow bay on the lake. A rather large snapping turtle swam towards our boat. He had two leeches attached to him, one was on its head and the other between his nose and an eye. We enticed him closer with a tasty perch, and Dave used pliers to remove both leeches. The turtle ended up eating seven perch, which were originally slated to bring home for my parents!”
6/2:Sharon Lintereur sent a photo of a barred owl poking its head out of a nest box that they made specifically for it in their Lake Tomahawk woods. An owl has nested in this box for several years and is likely the same female.
6/8: During the Mercer Lupine Fest, I led a bird walk on the Little Turtle Flowage. The highlight of our observations was watching a bald eagle harass an osprey in flight long enough that it dropped the fish it was carrying, and the eagle then swooped down, caught the falling fish in the air, and flew away. I’ve seen this a few times over the years, and it’s always a “Wow”!
6/9: The cottongrass bloom along Hwy. 47 in Powell Marsh is a veritable snowstorm of white.
6/10: Sarah Krembs sent me several excellent photos on 6/10 of a female Blackburnian warbler that had been collecting nesting material in her garden for several days. Blackburnians are notoriously difficult to see, much less get good photographs of a female collecting nesting material, so kudos to Sarah. I find the photos particularly interesting because they confirm the suspicion that our neotropical warblers are late in nesting this year. Our very slow to arrive spring led to an equally slow migration of many species into the Northwoods. Females typically incubate their eggs for 11-12 days, and the chicks will fledge in another 12 days.
6/10: We had a northern mockingbird visit our yard. Mockingbirds are very uncommon in the Northwoods, so we felt quite blessed that one found our yard to spend its day.
Turtles Laying Eggs Now
Snappers and painted turtles, along with a few highly uncommon wood and eastern spiny softshell turtles, are laying eggs right now throughout the Northwoods. It’s important to protect these turtles given that only 5-10% of the eggs they lay are estimated to hatch (lots of predators out there!), and then only 1-3% of those hatchlings will live to become adults. Thus, for every 100 eggs, fewer than 1 will make it to adulthood, a daunting prospect if you’re a turtle. So, slow down if you see one crossing the road and do what you can to slow others down, too. And, if they’re nesting on your property, you might consider fencing off the nest as soon as the eggs are laid to protect them from predators. Hatching won’t occur until late August and into September, at which time you can remove the temporary fence.
Palmer Drought Severity Index
We’ve finally had a stretch of dry weather in early June which has helped reduce the extreme high water in our area. To see graphs of water conditions nationally and regionally, search for the “Palmer Drought Severity Index.” I’ve attached their graph of the Wisconsin Statewide Drought Severity Index for January through April from 1895 to the present which shows this spring to be the second wettest the state has experienced over the last 124 years, only exceeded by a spike in 1973.
Celestial Events
Jupiter is the star of the evening sky show this month. Look for it in the southeast after dusk. And while you’re looking in that direction, you should be able to find Saturn low and just to the east. On 6/16, look for Jupiter two degrees below the waxing moon. The full moon occurs on 6/17 – the “Strawberry/Rose/Honey” moon. Summer solstice officially occurs on June 21, but from 6/17 – 6/24, we’ll experience our longest days – 15 hours and 44 minutes. On 6/18, look for Saturn just above the moon. Our days start growing shorter on 6/25.
Thought for the Week
Arthur Carhart in a letter to Aldo Leopold in 1919: “There is a limit to the number of shorelines on the lakes; there is a limit to the number of lakes in existence; there is a limit to the mountainous areas of the world, and . . . there are portions of natural scenic beauty which are God-made, and . . . which should be the property of all people.”
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
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