By R. R.

BRANSTROM

Escanaba Daily Press

STONINGTON — As weather gets cooler and days get shorter, monarch butterflies in the north prepare to migrate south. Peninsula Point, the lighthouse at the end of the Stonington Peninsula which divides Big Bay and Little Bay de Noc, acts almost as a beacon, its nearby cedar trees gathering points in which monarchs from the Upper Peninsula and Canada roost and warm themselves before flying over Lake Michigan. Butterfly populations have decreased in recent years, but diligent volunteers across North America gather invaluable information for the universities and organizations who analyze and comprehend the data.

While not every community reports counts every year, Sue Jamison, who coordinates the efforts on Stonington, is proud to say that their group has presented data every year since 1996.

Milkweed is the only plant on which monarch butterflies lay eggs. There are two fields on Stonington in which volunteers check milkweed every Wednesday morning during the time of year when larvae are present — usually between June and August. According to Jamison, two volunteers use an orienteering compass and count the number of plants within a “shoulder-width path” and record the number of larvae and how many of each instar stages are seen. There are five instars of monarch development. Jamison said she submits the data to the University of Minnesota for the Monarch Larva Monitoring Project, which was developed in 1997. The project, now led by University of Wisconsin-Madison Arboretum, plays a key role in the Monarch Joint Venture, which is “a partnership of federal and state agencies, non-governmental organizations, businesses and academic programs working together to protect the monarch migration across the United States.”

The monarch butterflies that are in the U.P. during the summer have a short lifespan — around two to six weeks — whereas the migrating generation lives for six to nine months. That vast difference is due to activity and metabolism, said Chip Taylor, founder and director of Monarch Watch at the University of Kansas and a founding member of the MJV.

Summer monarchs are sexually active and exert a lot of energy and die without traveling very far. Those that migrate fly all the way to Mexico — where they overwinter — and don’t reach sexual maturity until the spring. Some call them the “super generation.”

The same butterflies that are leaving the U.P. and Canada now begin the journey back up usually around late February, Taylor said. After leaving Mexico, the mature monarchs lay eggs in Texas, Oklahoma, and other parts of the south and then die; their offspring continue to head northward by the end of April through May and early June and are the ones seen in the U.P. at that time. Two more generations hatch, breed, and die in the north in the summertime. The third generation stops at Stonington on their way south.

“Monarchs east of the Rocky Mountains will migrate to Mexico. Monarchs west of the Rocky Mountains just go to California,” said Sue Jamison. She said that when she enters her data for the Monarch Larva Monitoring Project, she checks other pins on the map. But as not all of the places that have reported in the past supply data each year, it’s hard to know for sure whether that means they no longer see monarch larvae or there are no longer volunteers to do counts.

Chris Leeseberg, forest biologist with the U.S. Forest Service in Hiawatha National Forest, said that larval counts have been good so far this year and he expects a decent number to pass through Stonington before flying over the lake to Door County, Wis., which is northeast of Green Bay.

“Peninsula Point at the end is a perfect place for them to funnel down,” said Jamison. “They roost in the cedar trees; they’ll fly down there at night. They like the cedar trees because they’re dense and they offer them protection. They’ll be on the trees with their wings closed.”

According to Jamison, volunteers usually begin roost counts at the grounds around the Peninsula Point Lighthouse the third week of August. But as the migration is weather-dependent, the timing fluctuates. One resident, ideally situated on one of the last private roads at the end of the Stonington Peninsula, is perfectly positioned to act as eyes in the field.

“As the crow flies, I’m probably a mile from where we count larvae and everything. But I see the activity rate on my beach, so I monitor my own beach as well,” said Opal Hoffman. Her updates keep Jamison informed. Once the migration begins, Hoffman said, she’s at the point almost every day. The monarchs’ arrival isn’t consistent or especially predictable — while it’s common for them to roost overnight and leave when the sun and wind are right, sometimes none will be there at 8 a.m. (the usual morning check time) but a second trip at 11 a.m. will have found groupings.

The butterflies cluster together in the cedars to keep the chill away and conserve their energy before becoming active. They seem to enter a torpor state that sounds almost like the hibernation Chip Taylor described happening in Mexico.

“If the temperatures are high enough, some of the butterflies will leave the clusters and seek water. They’re living off of fats that have been accumulated during the migration, and living off those fats means that they have to have water to metabolize, to break down the fats,” said Taylor. “When they need to get water, they’ll go off to places where there’s a lot of condensation or something of that sort. So they’ll fly off in the morning, maybe starting at 9 in the morning, and by 4 in the afternoon, they’re all back up in the clusters.”

That happens during a long period in winter after making this long journey. Before, they also become very still as they hang in the trees at Peninsula Point.

Hoffman referred to it as a “zone” and said, “When they really get going, it’s like night and day. They’ll be hanging there, and then the next thing you know, it’s like instant awake. Something tells them it’s time to go.” She said that on mornings when a tree is covered with immobile roosting monarchs, they begin to move when beams of sunlight reach them.

Counts at the lighthouse begin soon. Jamison said that volunteers and Forest Service employees will help gather information, and that they try to have someone out there every day.

“We check for the monarchs; we also record the time of day, the temperature, what the wind speed is, the wind direction — you know, all of those things — the visibility of the sun … we record all of that,” said Jamison.

The butterflies favor a north wind to help carry their trip and sunshine to warm their wings. In the past, reported Hoffman, west winds have caused many monarchs to travel to the eastern end of the U.P. and cross at the Straits of Mackinac instead.

Both women pointed out that the clusters don’t fly out all at once; there are different groupings. Jamison said it may only be 15 at a time. Hoffman said that last year’s total count at her property was disappointingly low, but there have been years she’s seen thousands arriving at once. There are usually about five waves of migrating monarchs per season, Hoffman explained. She shares her sightings on social media, which tends to create a buzz.

Data will be collected until those on the lookout stop seeing monarchs. The migration can usually be observed on Stonington Peninsula through mid-September.