Like September, its fall mirror image, April annually ushers in perhaps the most change in what the flora and fauna looks like in the region. Deer begin to switch from muted gray to reddish and tawny coats. Red squirrels also shed out their gray undercoat for a more fiery hue. Insects, amphibians and snakes emerge. Trees and shrubs put out the first leaves and buds; willow have catkins already, their equivalent of flowers that in the coming days will sprout pollen for when the first bees begin foraging.

And, of course, a host of birds are making their way through the region. Common grackles, red-winged blackbirds and robins are back in number. An early turkey vulture has been spotted in the Iron Mountain area, with more likely this coming week.

At Six Mile Lake, the past week was heavy on sparrows, with a few new ducks making use of the ever-widening pools in the ice. Seen were wood ducks, common and hooded mergansers and, of course, mallards. All of these annually are the most likely to show up with the lake still dominated by ice. A few Canada geese have touched down as well but for now do not seem to be staying long.

The sparrows, too, probably are just passing through. Most of what has appeared so far in the yard are species known to breed in the far north. They’ll spend some time fueling up for the rest of the flight before moving on when the winds are favorable.

A hooded merganser shows off at Six Mile Lake.

The majority were American tree sparrows, which generally can be identified by having a rusty orange cap and, unlike the similar chipping sparrow, a dark spot on its breast and a yellow lower beak.

This bird is somewhat misnamed, as it nests on the edge of arctic tundra so mostly breeds in Canada. It got the name from European settlers who thought it looked like their native tree sparrows, according to the Cornell Lab of Ornithology’s All About Birds website, allaboutbirds.org. It turns up here in spring and fall, making the journey to and from Canada, when it might linger by feeders but generally favors areas with open fields so doesn’t tend to stick around much here in winter.

The larger, rounder and more richly colored fox sparrows prefer the far north for nesting as well, so it’s not surprising to see them mingling with the tree sparrows, as they’re headed in the same direction.

The song and white-throated sparrows, however, may decide to raise a family in the area, though for the song sparrow the U.P. and northern Wisconsin are the southern end of its breeding range.

The song is good-sized for its kind as well and has bold streaks on back and breast but not the vivid red-brown spots and blotches of the fox sparrow.

The white-throated sparrow, shown here, and American tree sparrow, below, are familiar to the Upper Peninsula in spring.

The white-throated is noteworthy in it has two color forms — one with white streaks on its head, the other tan streaks. While the colors do not denote different sexes as with some other bird species, it apparently does play a role in how white-throated sparrows choose a mate, according to All About Birds.

“The two forms are genetically determined, and they persist because individuals almost always mate with a bird of the opposite morph. Males of both color types prefer females with white stripes, but both kinds of females prefer tan-striped males. White-striped birds are more aggressive than tan-striped ones, and white-striped females may be able to outcompete their tan-striped sisters for tan-striped males,” the Cornell Lab of Ornithology web site states.

The other oddity about the white-throated is it occasionally hybridizes with our familiar dark-eyed juncos, which while in the sparrow family is not a close relative and, as All About Birds notes, doesn’t look much like either color of white-throated sparrow.

All the sparrows are fun to watch as they scratch like mini-chickens in the leaf litter or ground under the feeders, looking for what they can turn up.

In the coming days, watch for sandhill cranes, yellow-bellied sapsuckers, belted kingfishers, osprey and perhaps the first of the northern flickers and eastern phoebes. If the weather warms a little more, turtles may begin basking as well even if some ice remains on area lakes.

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One creature that might not be expected this time of year is a butterfly, as normally butterflies and moths will spend the winter as pupae or caterpillars, with further development suspended until spring finally establishes itself.

But the region can host several varieties of butterfly that manage to tough it out through the winter as adults: the mourning cloak, the Compton and Milbert’s tortoiseshell, the eastern and gray commas and the question mark. Most annually will vary in number, some years scarce, some abundant.

This year, the most frequent I’ve seen have been the mourning cloak — velvet-brown with wings edged in blue spots and gilt-cream — and the Compton tortoiseshell, shown above.

Both spend the winter tucked into tree holes, crevices in rocks and other spaces where they can hibernate undisturbed.

Seeing them flit across the last of the snow on the first warm days of the season can provide one of the first indications that the region has turned the corner into spring.

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