Tag Archives: Wooly Bear

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

This Week at Bear Creek: A Cold Week, but Spring Keeps Coming

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

Look for this feature early each week! Cam Mannino shares her latest observations, photos, and inspirations from Bear Creek Nature Park. Don’t forget to check out the Preview of Coming Attractions at the bottom of the post to see what you should be looking for in the coming weeks. Thanks Cam!

 


 April 19 to April 25, 2015: A Cold Week, but Spring Keeps Coming

The Wood Frogs (Lithobates sylvaticus) are still singing and I thought I’d follow up last week’s swimming photo with one of this masked frog in the woodland habitat where it emerged this spring. This amazing frog migrates uphill in the fall, buries itself in the soil beneath the leaf litter where it freezes and then thaws in the spring. He’s camouflaged nicely against the leaves, isn’t he?

Frog in leaves
Wood frog in leaves

Bear Creek provides both kinds of habitats the Wood Frog needs to thrive – high, dry places for winter and nearby vernal pools for spring mating. Another reason our park is special and one of many good reasons for preserving wetlands.

Here’s a recording I made this week of frogs singing at a vernal pool. Turn up your volume and (after you hear me shuffling with the device a bit) you’ll hear frogs, the brrrrrt call of a Red-winged Blackbird and the repeated clear notes of the Northern Cardinal’s spring song. See if you can identify the frogs singing (http://www.paherps.com/herps/frogs-toads/)!

 

Blooming slowed, but persisted this week despite the cold.   Last week the American Pussy Willow (Salix discolor ) on the small loop behind the center pond looked like this:

Pussy willows
Male pussy willow catkins waiting for warmer weather.

 And here’s the same plant this week with a maturing male catkin (pollen producing flowers) turning bright yellow as it readies itself to release pollen. Pretty dramatic change, eh?

pussy willow getting ready to bloom
Pussy willow blooming. Pussy willows have male and female flowers on separate plants.

Migrating birds, seemingly undaunted by chilly temperatures, arrived this week – some to stay, some to rest for a week or so before moving farther north. I saw four, but managed to get my own photos of only two.

An Eastern Towhee (Pipilo erythrophthalmus), back from Mexico, Central or South America, perched on a high branch to sing his famous song, “Drink your teeeeeea” followed by a click.

Eastern Towhee
Eastern Towhee

I tried, really tried, to get a photo of the Ruby-crowned Kinglet (Regulus calendula) among the brush in the vernal pool north of the playground. But he just wouldn’t sit still and he’s tiny – smaller than a Black-capped Chickadee.   Because he was excited, however, he flashed his bright red cap against his gray-green body and we spotted him.  He’s just passing through on his way to cooler breeding grounds farther north in the US or Canada. He’ll probably depart by the end of next week. Here’s a link for a photo from a favorite website for bird study, Cornell University’s All About Birds website:

http://www.allaboutbirds.org/guide/Ruby-crowned_Kinglet/id

At the back of the pond just west of the playground, a bright flash of yellow, black and white streaked across my binoculars, but the Yellow-Rumped Warbler never sat on a limb for more than 6 seconds. (I counted!) But I got a very lucky shot a while later as he landed suddenly on a nearby branch. The black mask means he’s male. If you look closely, he actually has a patch of yellow on the top of his tail and one on his head, too, which isn’t visible here in his about-to-take-off pose.

Yellow-rumped Warbler
Yellow-rumped Warbler

Two kind birders in the park pointed out a pair of Blue-winged Teals ((Anas discors) at the far end of the pond west of the playground. Though I could see these smaller ducks through binoculars, they were resting in mottled shadow, so no decent photo.  They’re probably moving through our area but can sometimes breed in southeast Michigan. Let me know if you see them in the summer! Here’s another link to Cornell University for a photo of this distinctive duck with a vertical white stripe behind his bill.

http://www.allaboutbirds.org/guide/blue-winged_teal/id

Normally the Northern Flicker (Colaptes auratus) appears poking his long, curved beak into the ground as he searches for ants. Flickers have a bright red crescent at the back of the head, a black bib and the male sports a snazzy black mustache.

Flicker on ground
Northern Flicker on the ground

But one morning this week in the same vernal pool where the Kinglet darted, a male Flicker drummed persistently on a dead tree and shouted his piercing, somewhat maniacal call as a way of establishing his territory. Here he is, a bit blurred due to the distance.

Northern Flicker drumming on a tree
Northern Flicker drumming on a tree

And here’s is a link where you can hear his call. (Click on the second sound bar.)

http://www.allaboutbirds.org/guide/northern_flicker/sounds

Overhead, flew one of the most beautiful predators in the park, a Red-tailed Hawk ((Buteo jamaicensis).

Red-tail Hawk in flight
Red-tail Hawk in flight

Look closely at this much smaller set of wings! It’s not a wasp; that’s a disguise to fool would-be predators. It’s a Hover Fly. Although they mimic bees or wasps, hover flies can’t sting (hooray!) and they help out by preying on pests and pollinating flowers. So maybe that insect nuzzling your flowers is just a harmless hover fly!

Hover fly, Helophilus trivittatus. If you're an entomologist and have a better guess at the ID, please let us know!
A hover fly, likely Helophilus trivittatus. Hover flies are in the insect family Syrphidae, whose members mimic bees and wasps (though without the sting as adults mostly eat nectar, pollen, and aphids).

COMING ATTRACTIONS!

The well-known Wooly Bear Caterpillar thawed after freezing solid this winter and wriggled quickly through the grass. Those beady little eyes are looking for a place to metamorphose into an yellow/orange Isabella Tiger Moth (Pyrrharctia isabella).

Wooly bear
Wooly bear

After the prescribed burn in the northeast area, the woods are greening with wild strawberry leaves that will fruit in June. (Forget it – the critters always get them first.)

Wild strawberry leaf
Wild strawberry leaf (Fragraria virginiana)

Wild geraniums (Geranium maculatum) leaves are just poking through the blackened but newly fertilized soil. By mid-May, they will carpet the woods in a lavender haze.

Wild geranium leaves
Wild geranium leaves

The Other Side of Stewardship

And lastly, my favorite park denizen, my husband, Reg. On Sunday, he waded into the mud with a hook duct-taped to an extension pole and snagged 13 cans, 7 plastic bottles and various other detritus around the southern deck of the big marsh – oh, and a baby’s shoe from the vernal pool north of the playground. My hero!

Reg helping out.
Reg helping out.

As always, please feel free to share in the comments section below so we can all be on the lookout for your discoveries in Bear Creek next week!