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Butterfly splendor on full display in June

Northwoods Notebook

Betsy Bloom/Daily News photos Canadian tiger swallowtails “puddling,” in which they gather around a puddle or damp spot to sip minerals dissolved in the water.

This is a good time to see on display a number of butterflies that use different strategies to avoid perishing during the winter.

The most spectacular out right now are the Canadian tiger swallowtails, which have emerged in force after spending the cold months as a pupa attached to a tree or tucked into leaf litter. Like a number of other species, such as spring peeper frogs, swallowtail pupae can produce a type of natural antifreeze that protects them in winter.

With an average wingspan of about 3 inches, Canadian tiger swallowtails are the largest butterflies in the Upper Peninsula and northern Wisconsin, though southern Wisconsin has the slightly larger Eastern tiger swallowtail and giant swallowtails that can be more than 5 inches across.

Abundant in late May and June, Canadian tiger swallowtails usually disappear in July; any seen here later in the summer likely are hybrids from where ranges overlap in central Wisconsin with the Eastern species, according to several online sources.

But their caterpillars might be found later on host plants that include birch, aspen and black cherry.

A question mark, one of the “punctuation” butterflies that will survive winters as adults by tucking themselves away among dead leaves or cracks in trees or rocks. While a well-known butterfly, it is considered fairly uncommon.

Also now flying again in the region are monarch butterflies. They use their famous migration to escape the north, covering thousands of miles to reach the cool oyamel forests in Mexico’s Sierra Madre Mountains, according to the U.S. Forest Service. There they cluster together in tree tops and rely on fat reserves to survive to early spring.

The ones now in the Upper Peninsula are the offspring of those that made the fall journey, produced earlier this spring in southern states that already had milkweed available as host for the caterpillars. With the early start plants have gotten in the U.P. and abundant rainfall, the monarchs are finding the milkweed here already tall and the nectar sources abundant.

Earlier this spring red admiral numbers appeared to be up in the region. Like the monarchs, these black butterflies broad, semi-circle bands of red-orange on each wing are migratory but much less predictable, scarce in some years, present in profusion in others, according to the Wisconsin Butterflies website, https://wisconsinbutterflies.org.

No definitive answer has been found so far for why red admiral populations sometimes explode, the site states. But it had offered a possible explanation:

“An outbreak in Wisconsin in June would be the offspring of the first of these southern visitors, so it seems reasonable to conclude that weather conditions for overwintering Red Admirals to the south, combined with conditions during April and May when they are traveling, determine the number of butterflies we see here in Wisconsin in June.”

Again, it might be a result of the mild winter the region had this year.

A number of the native butterfly species do manage to endure the northern winters as adults, so they can take full advantage when the seasons finally turn. These include mourning cloaks, Milbert’s and Compton’s tortoiseshells and the “punctuation” butterflies such as commas. Most of these will have two generations in a summer, one in spring and the second in late summer that will tuck themselves into rock cracks or tree holes to hibernate.

Interestingly, the “punctuation” butterflies rarely nectar like the swallowtails but prefer to feed off decaying fruit and tree sap, according to several online sources.

Conditions this year seem ideal for a host of butterflies, so take advantage of the opportunity to get out and see what’s flying.

Betsy Bloom can be reached at 906-774-2772, ext. 240, or bbloom@ironmountaindailynews.com.

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