Rime ice etches the evergreen leaves of boxwood shrubs.
On the last morning of the year, soft gray clouds insulate the city. The air is still and quiet except for a few American robins and goldfinches calling. In the silence of the night, fog crept in and dressed every tree branch and plant with beautiful needle-like ice crystals.
When fog or mist droplets freeze instantly on contact with the wind-facing side of a cold surface, rime ice is formed. The milky white color of rime is caused by the air pockets between the ice particles.
How is rime ice different from hoar frost? First, they differ in appearance: Hoar frost often looks feathered and lacy, in contrast with the sharp needles of rime. They also form by different processes. Hoar frost typically forms on cold, clear nights rather than during cloudy conditions. Water vapor freezes and crystallizes on surfaces without becoming water droplets first. Both rime ice and hoar frost add a magical beauty to the monochrome winter world.
Rime ice’s sharp needle-like crystals decorate a garden obelisk.
A quiet trail in Minneapolis, Minnesota, glows with fresh snow and late-afternoon sun.
The “keeper snow” came early this year. In late November, we walked in lightweight clothing and running shoes. Two days later a storm blew in ahead of a Canadian cold front and dropped eight inches of new snow. We’ve entered the stark season. Green is a memory buried under an ice-cold blanket. Gone from our yard are the bumblebees, painted lady butterflies and other pollinators. I’ve put the garden to bed for the winter.
Black-capped chickadees (Poecile atricapillus) are high-energy winter residents in our back yard.
Just ahead of the storm, a mixed flock of robins, dark-eyed juncos, black-capped chickadees and small woodpeckers—both downy and hairy—descended into our back yard. Robins tossed aside leaves to uncover stray insects, seeds and fruit. Juncos sought seeds on the garden wall. Chickadees and woodpeckers hunted for insect larvae and other delights in the bark of our old apple tree.
This afternoon at dusk, a female northern cardinal, softly colored and alone, delicately plucked crabapples one-by-one in our front yard. She was lucky to find any because the portly gray squirrels have stripped most of the tree bare. I am grateful for these winged winter residents that bring life to our garden on even the coldest winter days.
A female downy woodpecker (Dryobates pubescens) excavates for insect eggs and larvae in a dead portion of our apple tree.
A painted lady’s (Vanessa cardui) underwing sports four eyespots and pink patches. It is nectaring on asters (Symphyotrichum oblongifolium).
Mild October days bring butterflies to our garden. We commonly see red admirals, painted ladies, commas and tortoiseshells, but in 2022, I’ve seen fewer numbers of butterflies all season. The only painted lady (Vanessa cardui) that I’ve spotted appeared in late October on a mild, sunny day (77°F/25°C).
It spent hours nectaring on late-blooming asters in the company of many bees, and flew energetically around the garden every few minutes. While most of the native bees perished in a hard frost (24°F/-4°C) more than two weeks ago, a few hearty bumblebees survived, as did the honey bee colonies. Bees and butterfly got along well and were simply focused on collecting nectar for energy. As I gardened nearby, the gentle humming of the bees was soothing and complemented the rustling of falling scarlet-red maple leaves.
A painted lady’s upper wings carry black and orange markings with a few white spots near the wingtips.
Two days later, the painted lady disappeared from our garden on a warm wind heading south. I miss them during the long northern winter. Also known as the “thistle butterfly,” (because thistles are a favorite food source for both caterpillars and adults), painted ladies migrate to wintering grounds in the southern United States and Mexico to return in late spring.
On a windy, warm September evening, the sun has set; the air is soft and dusky. Migration is underway, but not the avian sort. A few large common green darner dragonflies zigzag beneath the trees hawking insects. I look skyward and far above me, a river of swarming green darners surges — hundreds of them — straight south ahead of a cold front.
Born in Minnesota, these green darners migrate to the Gulf Coast of the southern United States and Mexico. When they arrive, they’ll mate and lay eggs to produce the next generation, which will migrate north in April or May. When they arrive here, they will mate and give rise to a new generation before dying. These progeny will hatch by late August and continue the cycle of migration and reproduction.
But that’s not the entire story! Common green darners are present in the north all summer — so where did they come from? There’s a resident population that doesn’t migrate. They’re active and deposit eggs throughout the summer and autumn. However, their young, called naiads, won’t mature until the following spring. They will wait out the winter on the bottom of a pond, marsh or slow-moving river or stream.
Averaging 3 inches in length, and with a wingspan of 3.5 inches, green darners are among our largest dragonflies. This one also is a female. Males’ abdomens are bright blue.
Green darner adults eat mosquitoes, midges and other flying insects. The aquatic naiads feast on mosquito larvae and other aquatic insects, tadpoles and tiny fish. Green darners are eaten by spiders, large robber flies and birds such as kestrels.
Male widow skimmers (Libellula luctuosa) are dark brown with a bluish frost called pruinose.
What do you think of when you hear the term skimmer? A shore bird, a kitchen utensil, or perhaps a type of shoe? Skimmer also refers to the earth’s largest family of dragonflies, Libellulidae.
Skimmers might be the image that many envision when they “think dragonfly.” Skimmers’ wings are large and patterned with spots — usually black and a powdery grayish-white. Like all dragonflies, skimmers hold their wings spread out horizontally from the body when resting. The head is large with eyes that contact each other on top. Two inches is a common body length, but it can vary between one and three inches. Adult skimmers dine on many soft-bodied insects, especially mosquitoes, flies, small moths and winged ants. Nymphs, or immature dragonflies, develop underwater where they eat mosquito larvae, fly larvae and other aquatic organisms. Skimmers are preyed upon by raccoons, skunks, shrews, bats, turtles, snakes, frogs, fish, spiders, larger insects such as praying mantids, and many bird species.
A female twelve-spotted skimmer (Libellula pulchella) perches on a dead forb in an urban oak savanna.
The twelve-spotted skimmer (Libellula pulchella) and the widow skimmer (Libellula luctuosa) are two common skimmers of Minnesota. Though similar in appearance and size (about two inches long), the difference is in their wing spots. Male twelve-spots carry 12 black patches and eight white spots between the black ones. Male widow skimmers show a dark black wing patch from the wing’s base to about midwing. One large white spot extends outward from the black patch. Female and young juvenile males of both species only exhibit black patches. Males and females of both species are coppery brown, but adult males develop a whitish-blue dusty or frosted appearance, called pruinose, on the abdomen. Both species sport bright, neatly etched side stripes — yellow in twelve-spots and orangish in widow skimmers. In addition, the thoraxes of mature twelve-spotted skimmers display two yellow stripes.
Why the name widow skimmer? One explanation is that most male dragonflies carefully guard their mates during egg-laying, but widow skimmer females deposit their eggs unguarded, and thus became commonly known as widows. Another is that the black wing patches were thought to be reminiscent of a widow’s shawl.
A female widow skimmer’s wings show the black pattern reminiscent of a widow’s shawl.
Both skimmer species may be found near ponds, lakes and marshes, but they also venture away from water into fields and meadows. I observed two twelve-spotted skimmers in a small area of oak savanna in Saint Paul, about three city blocks away from a pond. One perched on a dead tree limb, the other atop a dried up forb, wings spread horizontally and glistening in the sun.
Though not the most eye-catching of dragonflies, I like them; they’re easy to observe because they often forage in open areas away from water and remain close to their conspicuous perches. Both species share a similar geographic area. Twelve-spots range throughout most of southern Canada, the continental United States and northern Mexico. Widow skimmers occur in southern Manitoba, Ontario, Quebec and Nova Scotia, across the United States, except for the Rocky Mountain region, and in a portion of northern Mexico. Both skimmer species are on the wing during the summer months and the twelve-spotted skimmer is active through September.
Nature, Garden, Life 