Tag Archives: Mourning Cloak

Bear Creek Nature Park: So Much to See When There’s “Nothing to See”

White Oak leaves under water at the Center Pond with tree reflection

At first glance, Bear Creek Nature Park in November doesn’t have much to recommend it.  A frequently gray sky glowers overhead. Insects don’t buzz, soar over or spring out of the fields now drained of color. Birds only occasionally call but never sing. A casual observer might say that that there’s “nothing to see.” But they’d be wrong.

Blog and photos by
Cam Mannino

It just takes a bit more attention and a dash of memory to enjoy a late autumn hike. That quick little movement in the bare shrubbery could be a group of small golden migrators wintering here with us. Leaves skate across the pond’s first skim of ice or frame a bit of brilliant green and red moss. The birds that live with us year ’round are making winter homes and energetically seeking out bits of nourishment all around us if we look. Summer creatures snooze under the bark of trees and under the soil at our feet as we walk. Life doesn’t stop, even in November. We just need a bit more care to enjoy it on a November day.

Noticing November’s Birds – Blue, Red, Golden, Even Ones with Fancy Hairdos!

All month the Center Pond has shifted from water to ice and back again – but it’s always a place to watch with a keen eye. On the first bird walk of the month, the group saw Mallards (Anas platyrhynchos) as usual, calmly cruising at the far end of the pond. But then, wait! What about that bird with the bouffant crest? It seems that those sneaky Hooded Mergansers (Lophodytes cucullatus) may have added an egg to a Mallard or Wood Duck nest, as they occasionally do. The young female Merganser steamed up and down the bank at a snappy pace, as her Mallard companions paused to preen along the way.

That same early November day, the birders heard the “tsee, tsee” call and then saw a group of winter visitors from northern Canada, Golden-crowned Kinglets (Regulus satrapa). The flock was too quick-moving for me, so I’ve borrowed a lovely shot from iNaturalist.org’s photographer, Joanne Redwood. Though we saw these little Kinglets in bare shrubs, look for them mostly where there are lots of pines whose needles provide shelter for them on snowy days.

A Golden-crowned Kinglet photographed by Joanne Redwood (CC BY-NC)

Late in the month, a male Belted Kingfisher (Megaceryle alcyon) had claimed the center pond as his winter territory and found my presence quite annoying. When I spotted this guy, he was calmly gazing out across the pond with his crest lowered. But as I approached, his crest began to rise as he swooped between three trees at the eastern end of the pond, shouting his rattle-call to declare his territory. Female Belted Kingfishers usually migrate a bit south to be guaranteed some open water, which they need for fishing. But the males often stay north to protect possible nesting territory. When the pond freezes, though,  he’ll temporarily move south or to water that stays open in the dead of winter.

An agitated male Belted Kingfisher pauses for a shot as he defines his territory for me by swooping between 3 trees.

The next time I saw the mallards at the pond, the day was icy cold but the pond was still open.  Three males were “bottoms up,” feeding.

Three male Mallards go “up tails all” while feeding in the Center Pond.

On that same icy day, a large flock of Mallards on Bear Creek Marsh preened frantically, trying to keep warm by adding oil to their feathers from a gland beneath their tails. The oil helps align their feathers, providing maximum waterproofing and insulation.

On any icy day, Mallards in the marsh preen busily, adding more oil to their feathers for insulation and waterproofing.

On windy days, of which there were many this month, our year ’round birds seemed to retreat to the woods, where I suppose the tree density breaks the wind. I was surprised this week to see a female Eastern Bluebird (Sialia sialis) in the woods. I tend to see them most in meadows or open areas; that day she was just taking a break in the woods from gusting 20 miles-per-hour winds! So nice to see these bright blue birds on a gray fall day.  (Click on photos to enlarge.)

Black-capped Chickadees (Poecile atricapillus) scout out decaying snags, looking for a snug hole for winter nights. Sometimes they excavate one and sometimes they appropriate an old woodpecker hole. This snag  looked a little promising. The number of “dees” in a Chickadee’s call indicates how much danger is around. Fortunately, my husband and I only rated the average 3 “dees.”

The number of “dees” in the call of Black-capped Chickadee indicates how much danger it perceives.

A few minutes later, a White-breasted Nuthatch (Sitta carolinensis) decided to take it step further – either looking for possible insect eggs or perhaps exploring the depth of a hole in the same snag for a winter retreat. In winter, Nuthatches hang out with Chickadees and Titmice for protection and to take advantage of  possible food sources other birds may find.

A White-breasted Nuthatch explores a hole in the same snag graced by the Chickadee a few minutes before.

A “kwirr” call from high above alerted us to a Red-bellied Woodpecker (Melanerpes carolinus). This male definitely seemed to be foraging.  I think I spotted little insect eggs on his beak as he concentrated his attention on one spot in the bark. He can use his summer nesting hole in a dead tree or limb on cold winter nights.

 

Imagining and Remembering: Good Tools for a November Walk

On days when birds are elusive and the parks seem quiet, I watch for reminders of summer creatures who are hidden away, spending the winter underground, under water, or under bark and leaves all around me. Here are a few that came to mind during November.

The Raccoon’s (Procyon lotor) hole is empty now, but I bet there may be one or two sleeping deep in that well-used south-facing hole.

It looks as though a Muskrat (Ondatra zibethicus) built this unusual “push-up” den among the trees on a small mud flat in the Center Pond.  So there will be probably be one  swimming very slowly and eating in the air space inside the den during the winter.

Of course, some of the reminders concern summer visitors. This little nest we spotted during an early snow shower could be the summer breeding home of a variety of birds.  I’m no expert on nests, but I’m imagining that it could be that of a Chipping Sparrow since Cornell describes their nests as “a loose cup of rootlets and dried grasses so flimsy you can often see through it”  But that’s just a guess.

And this fragile, scrap of nest near the pond brings back memories of the faithful father, the Rose-breasted Grosbeak (Pheucticus ludovicianus) who patiently took his turn at the nest – an unusual behavior in male birds.  The nest was never very sturdy but autumn winds and rain have left only the base.

And this abandoned, tattered masterpiece was probably the home of some sort of Yellow Jacket species, perhaps the Bald-Faced Hornet (Dolichovespula maculata.)  The only surviving member of this once active hive would be the inseminated queen who is probably spending the winter under bark or inside a log nearby.  She’ll emerge to lay the eggs of future queens and future  workers whose infertile eggs produce the males.

Standing by a wetland pond in the park last week, I was reminded of the Salamanders (Order Urodela) who now must be hibernating under my feet. On a warm, wet night next spring, salamanders will wriggle their way to the water, lay their eggs on a stick and hide again under logs further upland. That’s where I found some of their young when the trees were green last spring.

The Mourning Cloak butterfly (Nymphalis antiopa) which can actually overwinter as an adult under bark or in a tree cavity might be camouflaged inside or on any tree you pass on your hike. The underside of it wings imitate tree bark when folded. The upper side, however,  features a white edge and a lovely band of blue spots when it flutters forth in early April, as you can see in this photo by inaturalist.org photographer Lewnanny Richardson.

Relishing Bits of Color Among the Autumn Brown

I crave color when the leaves have fallen and my eyes are still adjusting to the austere beauty of late autumn and winter.  Luckily nature still provides a few splashes here and there before the snow covers it all.  A sampling in the slideshow below.(Use pause button for captions.)

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Or If All Else Fails…

How about placing bets on which leaf wins the race across an icy Center Pond?  Here’s a silly 10 second video with faint “play-by-play” by my husband, Reg.

The Subtle Charms of Late Autumn Hiking

And adult and child venturing out on the Walnut Lane.

The pizzazz of spring and summer is past, the colors of early fall are memory, but late autumn, too, has its charms if you give it a chance. The last leaves high in the canopy are hushing in the wind. Take a moment to watch just one leaf dance and swirl its way down to the water. Or toss a milkweed seed to the wind and then watch it sail across a meadow. Have a closer look at a plate-sized mushroom on a log. Sit on a bench out at the marsh and watch the wind ripple the water or the cat-tail seeds shining like snow as they blow across the marsh. Let your cheeks tingle in crisp air after long hours indoors. I bet you’ll come back inside refreshed and with stories to tell. You’ll see…

Footnote: My sources for information, besides Oakland Township's Stewardship Manager Ben VanderWeide, are as follows: Caterpillars of Eastern North America by David L. Wagner; inaturalist.org;Allaboutbirds.org, the website of the Cornell Ornithology Lab at Cornell University; Wikipedia; Herbarium of the University of Michigan at michiganflora.net; various Michigan Field Guides by Stan Tekiela;Butterflies of Michigan Field Guide by Jaret C. Daniels,  and others as cited in the text.

THIS WEEK AT BEAR CREEK: Shrimp, Clams?? Yes! Plus Plenty of Spring

Quite a week at Bear Creek!  It began with 3 inches of snow at  30 degrees and ended at 70 degrees and sunshine! I began the week by joining Ben and two other volunteers (Catherine Hu and Antonio Xeira) in monitoring the creatures that live in our vernal pools – the wetlands that fill in the spring and mostly or completely dry by middle or end of the summer. I’ll be sharing both my photos this week and, with his permission,  the photos of Antonio Xeira, an avid birder from Portugal and a fellow lover of the natural world.

Blog post and photos by Cam Mannino
Blog post and photos by Cam Mannino

It turns out that Bear Creek’s vernal pools are teeming with life!  And new life began to assert itself in the rest of the park, too,  as the weather warmed. The first woodland flowers thrust out of the earth,  a few more migratory birds rode in on the wind, butterflies spread their wings in the sunlight, turtles basked and swam while the frogs  sang and salamanders left floats of eggs in the vernal pools. Finally, on a perfect spring Saturday, humans appeared on the playground lawn enjoying the spring sunlight with their fellow creatures.  A lovely week.

Who Knew Bear Creek Hosted Shrimp and Clams?

Antonio and Catherine OT0002
Volunteers Catherine Hu and Antonio Xeira examine their finds from a vernal pool.

Michigan Natural Features Inventory is leading a project to map and monitor vernal pools, something never done in Michigan before. Since these wetlands dry up for part of the year, they are particularly vulnerable to being filled in. But scientists are finding that vernal pools are “biodiversity hotspots” of the forests. Late fall or early spring flooding of these pools stimulates dormant creatures to awake and others to hatch as the water level rises. The “indicator species,” the ones normally present in a vernal pool, are, among others,  wood frogs, fairy shrimp,and a variety of salamanders.  We sampled four ponds and found evidence of these species.

Fairy Shrimp (Order Anostraca) are .5 to 1.5 inches long, swim upside down and look like a tiny version of the shrimp sold at the seafood counter!  According to the website of the Vernal Pool Association, their sets of 11 leaf-like legs do several things – propel them through the water, gather food (algae, bacteria etc.), and take in oxygen from the water.

Fairy shrimp3 OT0019
Fairy shrimp from a vernal pool

Here’s a female with an egg sac attached, and eggs visible inside!

Fairy shrimp OT0001
A female fairy shrimp with full egg sack attached.

Of course there are other small creatures in these ponds too – tiny Fingernail Clams (family Sphaeriidae), mosquito larvae and water beetles that row around with their front legs like oars! (Click to enlarge; hover cursor for captions)

Wood Frogs (Lithobates sylvaticus) love these ponds. We found brown ones and one tiny rust-colored one underneath a log. They come in varying shades of brown and, according to Wikipedia,  some are able to change their shade! (Both photos by Antonio Xeira)

The salamanders had already mated, laid their eggs in the water and disappeared under logs or leaf litter. But their egg sacks, attached to twigs, were pretty impressive!  Ben thinks the larger egg masses are Spotted Salamander (Ambystoma maculatum), with Blue-spotted Salamanders (Ambystoma laterale) laying smaller egg masses or individual eggs.

Meanwhile in the Sunshine…Birds!

More migratory birds are passing through to cooler climes or coming to spend their summer with us. One late afternoon on the far side of the Center Pond, I watched a Belted Kingfisher (Megaceryle alcyon) perch, watch carefully and suddenly dip down into the water with a rattling call.  Belted Kingfishers excavate 3-6 foot bank-side tunnels for nesting which slope upward to keep out water. Fossils indicate that they have graced ponds for 600,000 years! This fellow was a male; a female has a rust-colored belt across her belly, making her one of the few female birds who are fancier than the males.

Belted Kingfisher 2
A Belted Kingfisher makes a rattling call before dipping down to eat from the Center Pond.

The Kingfisher will spend the summer with us, as will the Northern Flicker (Colaptes auratus).  These beautifully spotted birds can be identified  in flight by a flash of white on their rump.  They’re high in the trees now, probably searching out nest holes. But since ants and beetles are a favorite meal, you can spot them poking their long beaks and barbed tongues into lawns or trails too.

Flicker Walnut Lane
An unusual posture for a flicker who normally uses its barbed tongue and long beak to probe the ground for ants and beetles.

A tiny migrant arrived this week too, the hyper-active Ruby-Crowned Kinglet (Regulus calendula). With a constantly flicking tail, these restless birds move from branch to branch, rarely alighting for more than a few seconds. This one is just passing through on its way to breed somewhere in Canada.  Its “ruby crown” only appears when it’s excited so I guess this one felt relaxed, despite its hyper behavior.

Ruby-crowned Kinglet
This Ruby-crowned Kinglet is just stopping by on its way to spend the breeding season in Canada.

A pair of Eastern Phoebes (Sayornis phoebe) hung out near the kiosk at Gunn Road. They were clearly checking it out as a possible nest site. Once she starts laying eggs, however, the female will chase this male away from her mud-and-grass nest.

Phoebe BC
A pair of Phoebes were checking out the kiosk near Gunn Road as a possible nesting site.

I don’t often see American Goldfinches (Spinus tristis) at Bear Creek during the winter, though they stay in the area.  My theory is that they’re all at neighborhood thistle feeders! But admittedly, they’re easier to spot now that the males have donned their bright yellow summer feathers.

Goldfinch BC
A male American Goldfinch has molted into its bright summer colors.

Flowers and Butterflies – It’s Definitely Spring!

Most years, I don’t see any woodland flowers until later in spring. The earliest to emerge are usually Spring Beauties (Claytonia virginica). But right now at Bear Creek, those lovely little flowers have only their leaves coming out of the ground in the dappled light of the woods.  But another of my early spring favorites, with the un-poetic name Bloodroot (Sanguinaria canadensis), is blooming along the western side of the Northern Loop. Notice how the flowers arise before the furled leaf below has opened – unusual in plants. The leaf will make a circular cloak around the flower once it’s fully open.

Blood root BC
The leaves of the Bloodroot unfurl after the flowers appear, eventually making a round cloak around the blossom.

Two butterflies fluttered over my shoulder on Saturday. Both of them spent the winter months as adult butterflies, hibernating in a frozen state under loose bark or in tree cavities. Mourning Cloaks are frequently the first butterflies out and about  in the spring which means they start the mating process earlier and have more broods than many migrating butterflies or ones that hatch in the spring. This one quickly winged its way to the Oak-Hickory forest – perhaps hoping for oak sap to rise soon and fill wells made by sapsuckers.  Sap is one of its favorite foods. Nice winter camouflage, eh? It looks like loose bark, especially with its wings closed. The Mourning Cloak has blue spots on it wings when they are open.

mourning cloak (1)
The Mourning Cloak emerges early in spring after hibernating under loose bark or in a tree hole all winter.
Winter-form Eastern Comma
Winter-form Eastern Comma

A small Eastern Comma (Polygonia comma) fluttered around me, landing on the trail. It also favors tree sap and spends the winter in frozen hibernation as an adult. The one I saw Saturday was tiny, restless and hard to photograph but it was still wearing winter colors – hindwing mostly orange with black spots (in photo at left). In the photo below, taken in a previous June, a summer-form Eastern Comma sports dark hindwings.

eastern comma butterfly
A summer-form Eastern Comma, with mostly black hindwings

Basking Feels So Good in the Spring!

A Garter Snake (genus Thamnophis) had climbed onto a small tree in one of the vernal pools we monitored last Monday and dropped into the water as Antonio, one of the volunteers, approached. No doubt it was interrupted while trying to soak up some sunlight after frigid Sunday weather.

antonios snake cropped
A snake probably basking in a small tree, dropped into a vernal pool where Antonio Xeira took its photo.

Fourteen Painted Turtles (Chrysemys picta)shared logs in the Center Pond, soaking up the sun of the first really warm day. Like snakes, turtles are reptiles which can’t regulate their body heat except through activity. So most warm days turtles stick out their heads, necks and legs to capture the sun’s heat on their extremities as well as their dark shells.

14 Painted Turtles
Fourteen Painted Turtles soak up the sunlight at the Center Pond.

I saw my first Snapping Turtle (Chelydra serpentina) on Saturday as it cruised the marsh. It was feeding below the water with its long neck and then poking its head out for a breath of air. It must feel great to eat and swim after a long winter under the ice.

Snapper swimming marsh
A Snapping Turtle cruising the marsh for food and a little sunshine.

And human denizens of the park came to Bear Creek on Saturday to eat and bask in the warm sunshine, too. This family (whose name I unfortunately forgot to get!) graciously allowed a photo of their picnic on the grass with a lovely little human in a big hat to protect her from the spring sunshine.

Families picnicking BC
Families picnicking and basking at Bear Creek on Saturday afternoon.

So much life in this 107 acres, eh? Within the shady vernal pools, on logs at the Center Pond, on bare tree limbs, in the grass on the edge of trails and on the green carpet of  the playground, the park hummed with life by the end of the week. After a white-and-black, silent winter, the color and song of spring greet us like a warm smile. I hope you’ll be there, too,  smiling back.

Footnote:  My sources for information are as follows: Ritland, D. B., & Brower, L. P. (1991); Stokes Nature Guides: A Guide to Bird Behavior Volumes 1-3, Allaboutbirds.org, the website of the Cornell Ornithology Lab at Cornell University; Wikipedia; http://www.butterfliesandmoths.org; Herbarium of the University of Michigan at michiganflora.net; various Michigan Field Guides by Stan Tekiela; Butterflies of Michigan Field Guide by Jaret C. Daniels; University of Wisconsin's Bug Lady at www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/ for insect info; http://www.migrationresearch.org/mbo/id/rbgr.html for migration info; invaluable wildflower identification from local expert, Maryann Whitman; experienced birder Ruth Glass, bird walk leader at Stoney Creek Metro Park for bird identification; Birds of North America Online; Audubon.org; Nature in Winter by Donald Stokes, Trees in My Forest by Bernd Heinrich, Winter World by Bernd Heinrich, Savannah River Ecology Lab (Univ of Georgia); Tortoise Trust website www.tortoisetrust.org;  An Orchard Invisible: A Natural History of Seeds by Jonathan Silvertown; The Ecology of Plants by Gurevitch, Scheiner and Fox; other sites as cited in the text.

THIS WEEK AT BEAR CREEK: A Chickadee’s “Bed,” plus Insects Alive in Our Wintry World

insect tunnels on tree branch
The filigree of bark beetles on a fallen tree
Cam in red winter coat BC
Blog post and photos by Cam Mannino

During this cold week, when nature seemed pretty hunkered down – and I sure was! – I decided to explore how our local bugs get through the winter.  I’d always thought of insects as killed off by the cold – and many are – but others are biding their time and getting through the winter in surprising ways – like the bark beetle larvae which left their filigree in the fallen tree above.

A Chickadee’s Home for the Night?

But I did venture out at dusk to see if I could spot birds settling in for the night.  And a couple of Black-Capped Chickadees (Poecile atricapillus) obliged by disappearing into a snag.  One let its tail protrude from the hole long enough for me to locate it once it suddenly disappeared!

A closer look at the chickadee's tail coming out of its night-time hole
A chickadee’s tail protrudes from its night-time hole

When I tried lightening this hole on the computer, the little bird appeared to have turned its head straight upward to fit into the hole!  If that’s what really happened, I hope it found a more comfortable place to spend the night once I left. Perhaps just getting out of the cold, though,  is more important than a stiff neck.

Chickadee in hole for the night.jpg
The closest shot I managed to get of the chickadee in its hole for the night.

Now, Concerning the Winter Survival Strategies of Insects…

Bernd Heinrich, in his book, Winter World: The Ingenuity of Animal Survival,  claims“…there is no life-form on earth as diverse, varied, tough, and inventive as the insects. ”   Heinrich’s adjectives – diverse, tough, and inventive – certainly apply to the varied and creative strategies that our Bear Creek insects employ during the winter months!   So now,  while walking along the snowy trails, I can imagine all these small creatures swimming under the ice, tunneling beneath the bark, dozing in tree holes or eating inside plant galls, waiting like we all are, for the burgeoning of spring.

Wasps, Hornets, Bees and Ants:  Long Live the Queen!

This category of insect winter survival has two sub-strategies.  Almost all wasps, hornets and many bees, including our native Bumblebees (genus Bombus),  live only one season.  After mating in the fall, the only member of the hive that survives is the fertile queen.  She leaves  the hive and inserts herself into a crevice in a log or under bark – some moist place in which she won’t dry out as easily in the winter.  If she survives, she rouses in the spring and goes off to find a new nest location, lays eggs and the hive begins again (click on photos to enlarge or hover over them for captions).

European Honey Bees (Apis mellifera)and Ants (family Formiciadae) have a different strategy – staying in the hive with the queen, and protecting her during the winter. Honey Bees eat honey during the winter and they keep their hive and the queen warm by fanning their wings. They were imported from Europe because this survival strategy meant that Honey Bees dependably provided honey and crop fertilization from the same hive year after year.

Ants lower their metabolism in the winter and pile onto their queen in order to keep her warm. I believe I saw evidence of Carpenter Ants (genus Camponotus) in this tree on the western trail through our Oak/Hickory forest last summer and fall.

Carpenter ants
Possible evidence of Carpenter Ants who chew wood to create galleries between areas of their nest and then deposit it outside.

Carpenter Ants don’t eat wood like termites; they chew it to make the galleries that connect parts of their nest, and then deposit it outside. Assuming that these were Carpenter Ants, they will have moved deeper into the nest and are now hibernating together with their queen.

When spring warms a bee hive or an ant nest, bees and ants are ready to go, having survived the winter as adult insects.

Green Darners: Migration

A very small number of  insects migrate much as birds do. Those of you who read the blog this summer will remember that some of the Green Darners (Anax junius) head south in the winter.

Green Darner3
Some Green Darners, large dragonflies, migrate south in the winter and their offspring return in the spring.

According to National Geographic, these large dragonflies build up fat reserves and as cold weather sets in, some of them ride south on a north wind. Like avian migrants, they make stopovers to rest and feed along the way and, strangely, follow  the same flight paths as birds (don’t they worry about being eaten?). But unlike birds, it’s a one-way ticket for these Green Darners. They breed in the south and die and it’s their offspring that arrive the following spring.  Some Green Darners and many other dragonflies, though, use the following strategy.

Damselflies and Most Dragonflies:  Naiads under the Ice

Naiads appear in Greek mythology and children’s books (like C.S. Lewis’ The Chronicles of Narnia) as glamorous winged water nymphs overseeing streams, rivers, and fountains. The naiads under the ice at Bear Creek, however, are simply the homely immature life stage of the beautiful dragonflies and damselflies we see in the summer. In warm weather,  the females lay their eggs on vegetation  in the pond or marsh. Drab, wingless naiads with hooked jaws  hatch from the eggs.  Even in winter, these hungry carnivores are swimming about consuming mosquito larvae and other invertebrates.  After molting up to 15 times (some dragonflies take 3 years to finish molting!), they crawl up out of the water onto a plant, bend backwards out of their exoskeleton in one last molt and emerge in the warm sunshine as brightly colored and patterned dragonflies or damselflies like these:

A Quick Overview Before We Go On:  The rest of the insects I’m exploring here have a four stage development: 1) Fertile females produce eggs; 2) Larvae , which in butterflies and moths are also called caterpillars, emerge from the eggs and eat like crazy; 3) Pupae form. In butterflies, their bodies harden into their pupal form which  is called a chrysalis. Moths and many other insects spin cocoons and go through the pupal stage inside them; 4) Adults emerge from chrysalises or cocoons and mate to start the cycle again.  It turns out that different insects spend the winter alive and well –  but in different stages of development.

Overwintering as Adult Insects:  Mourning Cloak Butterflies

The adult Mourning Cloaks (Nymphalis antiopa) that we see in early spring emerge from bark crevices or trees holes where they hibernated during the winter (those woodpecker holes in snags do a lot of good, don’t they?).

mourning cloak (1)
Mourning Cloaks hibernate in tree holes so they can emerge in early spring to mate.

These early spring butterflies hatched the previous summer. They ate a little and then went into summer torpor, which is called “estivating.” In the fall, the adult butterflies became active again, ate to put on weight,  and settled into a hole to wait out the winter. In the spring, they emerge very early, sometimes when snow is still on the ground, and mate. And their eggs, larvae and pupae  begin the cycle again.

Overwintering as adults gives some butterflies an advantage since in early spring, there is less competition for food (tree sap, decaying matter) and fewer predators, since many birds haven’t yet returned from migration.

Overwintering as Pupae:  Spring Azure Butterflies

According to the University of Wisconsin Madison Field Station website, the tiny lavender/blue Spring Azure butterfly (Celastrina ladon) overwinters in the pupal stage that in butterflies is called a chrysalis. When the female emerges in early spring, she mates within hours of hatching, lays her eggs the next day and dies on the third – an extremely short adult life!

The Spring Azure overwinters, hatches, mates, lays egss and dies in three days!
The Spring Azure overwinters as a pupa.When the adult female butterfly emerges, it mates, lays eggs and dies in three days!

Larvae hatch from the eggs and eat for about a month. Each then forms a pupa (called a chrysalis in butterflies) and the Spring Azure stays in that form from early summer until the following spring! A long wait as a pupa for a very short time as adult mating butterfly!

Overwintering as Larvae (commonly called caterpillars): Bark Beetles and Woolly Bears

This overwintering strategy, like the Queen strategy of bees and ants,  takes at least a couple of forms – staying under bark or freezing solid!

Bark Beetles:  Busy Tunneling Under the Bark

Bark Beetles (family Curculionidae) are tiny insects (about 1/10 of an inch) that can survive the winter as larvae, pupae or adults. They are a major food source for woodpeckers, especially in the winter (so that’s why woodpeckers continuously peck at tree bark!). According to Donald Stokes’ book, Nature in Winter, adult insects bore through the bark to a softer inner layer. The males enlarge a “nuptial chamber” where mating takes place. The females then tunnel out into a branch or the trunk, under the bark, to lay their eggs. The larvae who hatch from the eggs make increasingly larger tunnels as they eat and grow during the winter.

Eventually, they form pupae under the bark from which adults emerge in the spring.  The adults  bore back through the bark and fly off to another tree. According to Wikipedia, some of these tiny insects become pests and kill trees, especially when climate change and other factors promote their survival.  Most, however, tunnel within weak and dying trees or aid in recycling the wood of dead trees.

Woolly Bear Caterpillars:  Freezing Solid!

Woolly Bear Caterpillars are the larval stage of the somewhat drab  Isabella Tiger Moth (Pyrrharctia isabella). These caterpillars, by the way,  don’t predict winter by their bands; they simply molt throughout the summer “becoming less black and more reddish as …winter approaches” (Bernd Heinrich, Winter World).  

Wooly bear
Woolly Bear Caterpillars freeze solid during the winter by supercooling and producing glucose, which works like anti-freeze, and then thaw in the spring to continue their life cycle.

In the fall, they curl up under leaf litter and survive the cold by a combination of supercooling (lowering their body temperature, even below 32 F!) and producing the glucose which functions as anti-freeze – just  like the spring frogs in a previous blog. They can even survive thawing and re-freezing throughout the winter! Their pupae can’t survive the cold, so they wait until late in March before thawing and beginning to spin their cocoons. Continue reading THIS WEEK AT BEAR CREEK: A Chickadee’s “Bed,” plus Insects Alive in Our Wintry World