Bear Creek is busy with autumn. Butterflies sip nectar from late season wildflowers. Bees store up pollen to feed the colony during the winter. Grasses, vines and other plants produce seed heads or berries for next year’s crop, providing food for bird and beast alike. Migrating birds stop by on their way south, eating and resting. Summer’s avian visitors, having raised young here, prepare for departure. Some insects hatch, munch on plants, breed and in turn, become a meal for others. And in moist areas, some life forms emerge that range from just weird-looking to gloriously creepy!
Autumn Prep: Late Season Foraging, Molting and Migrating
One sunny afternoon, a band of Clouded Sulphur butterflies (Colias philodice) fed and fluttered among the pale lavender blossoms of native Smooth Swamp Asters (Symphyotrichum firmum) just off the Eastern Path. What a sight to watch this small male, its golden wings with bold black edges quivering, as it approached for a sip.
Clouded Sulphurs produce many broods a year and perhaps this couple will produce a chrysalis that will overwinter and open in the spring. I’d love to see one then, since the chrysalis reportedly turns yellow with a pink “zipper” right before the butterfly emerges! The male is the one with black wing bands.
Nearby, a small Common Buckeye butterfly (Junonia coenia) was sampling the aster’s nectar as well. Native autumn wildflowers provide such a feast before frost descends!
Monarch Butterflies (Danaus plexippus) are sadly scarce this year after we saw so many at Bear Creek last year. According to the Michigan State Extension website, a severe March snowstorm in their wintering grounds in Mexico killed 50-70% of the Monarchs before they could migrate! But the birding group was lucky enough to spot a female in the western Old Field, feeding on a native New England Aster (Symphyotrichum novae-angliae).
Red-legged Grasshoppers are bouncing out of the grass like popcorn along the paths of Bear Creek. They are in the process of molting five times into bigger and bigger instars. This one, retreating under a leaf, isn’t quite adult yet.
At the Center Pond one morning, a Great Egret (Ardea alba) went fishing before migrating to Florida and the Caribbean. Hikers at Bear Creek report seeing a lot of them in the park in the last few weeks, which is great to hear! (Click on photos to enlarge; hover cursor for captions.)
Under a bench on the viewing platform, two male Mallards (Anas platyrhynchos ) were developing their mating colors again. They’d spent the last 6 weeks or so in their “eclipse plumage,” when they take on the brown-toned female coloring. As they preened last week, however, an iridescent band of green was developing above their greenish yellow bills. (The females’ bills are orange and black.) I wondered if their flight feathers were most affected by the molt that day, since they didn’t take to the water when I sat down on a bench.
Several days later, I saw a bit of drama featuring these males. One of them had finished molting into his full mating colors. He “got the girl” and the other didn’t. The mallard couple did a lot of synchronous head bobbing on the deck and then swam off together. The other male was left on the sidelines, I’m afraid. But he may find a mate once his molt is complete. Feathers evidently tell female Mallards something important about choosing a healthy male.
An Eastern Kingbird (Tyrannus tyrannus) periodically sallied forth to capture insects from high above the meadow east of the pond. Here’s a photo from last year so you can see it a bit closer. This solitary bird will spend the winter in a flock, eating fruits along the Amazon River in South America. Sounds like a long trip but a pleasant escape, eh?
A twitching of leaves in the low bushes below revealed the constant tail-wagging of a small brown bird. A migrating Palm Warbler (Setophaga palmarum) moved among the branches with a telltale patch of yellow under its tail and a dark eyeline. It probably spent the summer raising young in Canada’s far north and is on its way to Florida or the Caribbean. In spring, a male’s courting colors are a bright yellow breast and throat and a chestnut cap.
What appeared to be a juvenile House Wren chipped and scolded from a nearby shrub as I passed. It looks like a young one, doesn’t it? It’ll be traveling to Florida and the West Indies once it leaves Bear Creek, riding on a North wind toward southern warmth.
This week the birding group saw several migrators, but I didn’t get great shots. So here are three of last year’s photos of the birds we saw through binoculars this week. You might trying bringing your binoculars when you hike here and take a close look at any small, brownish birds in the bushes. We typically don’t get to see these warblers or kinglets except when they stop in our parks on their journey north or south. They spend the summer raising young farther north.
At the edge of a wetland, a Spreadwing damselfly with huge blue eyes, which may be a Spotted Spreadwing (Lestes congener), hung onto a twig. Spreadwings always perch with their wings half open and have pincers at the end of their abdomen – but their individual species names are hard to nail down. So don’t quote me on the name of this blue-eyed, bug-eyed character!
Seeds and Berries Mean Spring Prep, too
Plants pollinated in the summer are beginning to produce the seeds and berries that will guarantee their return next year. At the edge of the woods, False Solomon Seal (Maianthemum canadense) berries are ripening from mottled pink to red. Aren’t they pretty?
An aggressive native vine, Virginia Creeper (Parthenocissus quinquefolia), has thrived this summer and seems to be climbing in dense mats over trees and shrubs all over Bear Creek. It produces berry-like “drupes” (a fruit with a pit that contains the seed/s) on bright red stems that eventually turn brown. Many migrating and year-round birds feed on these berries, along with the occasional skunk or red fox.
Wildflowers are setting seed for next spring and the birds take advantage of that as well. Here are a few native flowers and their beginnings of seed formation.
And Now for Creepy Crawlies and Other Oddities
Ben’s new Stewardship tech, Heather Herndon, spotted a spectacular creepy creature on a rotting log. It appears to be a Leopard Slug (Limax maximus), a non-native who cleans up dead plants and consumes fungi, some agricultural plants and even smaller slugs! What an odd creature it is! According to Wikipedia, it is hermaphroditic, which means it carries both eggs and sperm. It does mate, however, exchanging sperm with another slug through a reproductive pore near its right tentacle. How strange is that? Slugs, like snails, are gastropods, but unlike snails, they can’t withdraw into shells. What’s odd, though, is that this slug actually has an internal shell behind its head that seems to be an evolutionary left-over, since it has no apparent purpose. So creepily cool, this one!
On our Wednesday bird walk, we spotted this wonderful web of an Orb Weaver spider. It was a big web and placed unusually high off the ground. Looks like the spider, who may be that tiny dot at the center, caught something near the edge of the web.
Cathy Rooney, one of the Park Protector nominees, put up on Facebook a wonderful video she found. It shows an Orb Weaver working meticulously to create a web just like this one. I found this version at YouTube so it should be accessible to any reader. Great find, Cathy!
Out in the Old Fields, the Common Milkweed (Asclepias syriaca) pods are preparing to break open and release their seeds. But this year, the Large Milkweed Bugs (Oncopeltus fasciatus) hatched in great numbers and are attacking more milkweed pods than usual. These insects inject saliva into the seed with their snout-like rostrum. The saliva dissolves the seed so the insect can vacuum it back up! Milkweeds are toxic and these insects are too once they feed. Their bright red color is believed to ward off predators by advertising that. In these two photos, early “instars” (developmental stages between molts) are on the left, and on the right are later and larger instars and one adult beetle. Thanks to the weather and this spring’s prescribed burn, the Milkweed is plentiful this year too, so we can hope that bugs won’t wipe out next year’s crop.
Fungi appeared here and there in Bear Creek after the heavy rainfall. Ben identified this white branching mushroom on a fallen log. It seems to be from genus Clavulina, most likely White Coral Mushroom, Clavulina cristata. Doesn’t it look like a tiny white forest? It’s believed to be mychorrizal, meaning it emerges from fungi underground that surround a tree’s roots and assist the tree in absorbing water and nutrients while the tree feeds the fungi. A beneficial symbiosis.
Like last year, huge fungi formed on the dead tree across from the Playground Pond. They are clearly some kind of polypore, or shelf mushroom, but I’ve been unable to nail that down. Anyone have a guess? They were so big this year that one of them collected water in which insects swam! On my last visit, though, only one was still on the tree. Either the downpours knocked them off or perhaps children did, like I saw two little boys try to do last year.
A little girl was delighted by finding a common Shaggy Mane Mushroom (Coprinus comatus) in the green grass of the playground field. It is beautifully ruffled, isn’t it?
It took a while to identify this mushroom, but I’m pretty sure it’s called an Elm Oyster Mushroom (Hypsizygus ulmarius) because they look like this and grow out of Box Elders (Acer negundo) at this time of year, like this one on the Western Slope did.
I know some people experience autumn as a somewhat melancholy season – flowers missing petals, tree shedding leaves, birds departing. The park quiets down as birdsong diminishes and the cricket song replaces frog song. Others find the riotous color of fall leaves and the crisp air exciting and invigorating and they love the fall. It can strike me either way, depending on the day.
For those who feel a bit sad at summer’s end, maybe it helps to remember that autumn is just the beginning of a long rest before spring. Trees take a breather from photosynthesis and live down in their roots for several months. Seeds are finding their way to the ground where they’ll reside until sunlight summons their hidden life back to the surface. Some birds, like some humans, depart for the south. But others, like the first little Dark-eyed Junco (Junco hyemalis) we saw this week, are winging their way from the north to spend the winter here where our winter weather suits them just fine.
If we’re curious and take the time to look, every season here offers beautiful – and sometimes oddly fascinating – discoveries. And that cheers me even on the grayest of autumn days.
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.