Northland Nature: Monarchs arrive soon for summer
Jun. 3—The ice-out was later than normal by about two weeks. The growth of the spring wildflowers, though quite prolific, was delayed more than a week due to the melting snowpack and thawing ground. Cooler temperatures also slowed the greening of trees in May.
Our waiting was worth it. As May was winding down, we had plenty of wildflowers with trees blossoming and leafing. Warming temperatures and moisture gave the spring that we were waiting for.
The bird migration was a bit slow in the Northland and the ice cover on rivers and lakes postponed the arrival of geese, swans, ducks and mergansers. Others, such as red-winged blackbirds and woodcocks, were also noted at a later date. Songbird migration in April was less than expected; the first warbler (yellow-rumped), phoebe, tree swallows, sparrows and hermit thrushes were all a bit late. And then we moved into May.
Instead of a month with temperatures considerably below the norm, they proved to be about normal, a blend of chill and warmth with plenty of precipitation. The rest of the spring migrant songbirds made their appearance. During May, we saw the return of the colorful and well-known rose-breasted grosbeaks, Baltimore orioles, scarlet tanagers and ruby-throated hummingbirds. And those not as well-known: thrushes, flycatchers, vireos, wrens and a huge variety of warblers.
It is interesting to note that most of these migrants came back at about the time expected. They did not appear to be delayed by the late arrival of spring. The reason for this is that many May migrants winter in the tropics. Wintering there, they did not deal with our colder-than-normal winter and late spring. And so, with the increasing length of daylight, they flew north.
This timing is important to these insect-eating birds. They need to be here when the insects emerge and caterpillars feed on the newly opening leaves. Warblers are often hard to see, but with the slow leafing, I saw many — 15 kinds in one day.
Now as their arrival lessens, we look for another migrant: the monarch butterfly. Probably the best-known (and loved) butterfly, their migration is well-documented. Spending summer in the Northland, they lay eggs on milkweeds. This next generation, maturing late in the season, will fly about 1,200 miles to the wintering site in the Transvolcanic Mountains of Mexico.
This southbound flight is done by the grandchildren of the ones arriving here in spring. After hanging onto branches in a mountain forest, they leave in late winter to go north.
Getting to the southern states, they locate new growth of milkweeds where they lay eggs and subsequently die. These young grow up on the milkweeds, and as adults, go north to our region, usually arriving in early June. I have seen some years when they are here before May 20; others are near mid-June.
Monarchs are large and mostly orange — rather easy to discern from other butterflies at this time. Also called "milkweed" butterflies since they lay eggs on this plant. Young caterpillars grow up feeding on milkweeds. (The name "monarch" is believed to have been given to them in honor of King William III of England, the Prince of Orange.)
Though some local butterflies hibernate for winter, most of the variety seen in June hatch from eggs or emerge from chrysalis. But the one that we look forward to seeing is a migrant. Once arrived, we will monitor the progress and populations of these summer monarchs.
