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Newsletter 40
Summer 2011

Come to the Festival

On Saturday, September 17, the meadow at the nature reserve will be transformed. Three large tents and a few smaller ones will have sprouted like fall mushrooms to house all manner of exciting activities. On stage will be performers in the Muskoka Wildlife show. The loud cry of a peregrine may come from the stage, or from the sky above as wild raptors fly past on their way west, then south to Central or South America. Do you like spiders? Then the Creepy Critters show is your cup of tea, or maybe you’d rather search for a yellow crab spider hiding in ambush in a clump of goldenrod.

The tap, tap, tap you hear may be a downy woodpecker hunting for grubs beneath the bark of a dead birch limb, but more likely it’s the sound of happy little "elves" building bird feeders at the Home Depot tent. Those tantalizing smells may come from the bake table in the north tent or from a burger on the Licks barbecue near the Waterfront Trail, or it could be the perfume from a deep purple New England aster blossom.

Want to get away from the crowds and explore the nature reserve? Why not join one of the guided nature walks. Let our enthusiastic tour leaders reveal some of nature’s secrets. Or follow the signs to the east side of the meadow for an up-close look as banders attach a numbered aluminum leg band to a white-throated sparrow to track its migration over the next months and years.

When you need a break, why not see what treasures are hiding in the Silent Auction tent, or check out the incredible variety of insects on display at the insect table, or borrow a net and go hunting for your own bugs.

Or maybe this is the year you’ll discover the secrets of master magician, Warren Toaze.

Help!!! Saturday, November 5
Garlic Mustard Removal
9:00 a.m. (rain dates: Sunday, Nov. 6; Saturday, Nov. 12)

We’re winning the battle, but we still need all the help we can get. Not able to get down and dirty at ground level? As they say in Australia, "No worries, mate!" We still need scouts to search and mark strays, or wield long-handled shovels to loosen plants. Someone else will take care of the "Destroy" part of the mission. Bring your favourite gardening weapon, or we can supply one. No need to tell you how to dress. After all, it is November. If it’s precipitating on November 5, we’ll scrub the mission until a later date.

P.S. If you sleep in, come late. No note needed (or detentions given.)

Gifts That Will Last Forever

Metres of the nature reserve have been saved in the name of:

Glenn Coady & Paula Brown Radovanovich
Donald L. Lloyd.

Thank you to everyone who gave a friend or loved one a share in this living legacy—a gift that will last forever!


Recent donations have been made in memory of these special people:

Dave Calvert
Brenda Carol Desnoyers
Joanne Griffith
Aileen Howes
Katharine Martyn

We join their families and friends in mourning their passing, and acknowledge their unique contribution to the rich web of life on planet earth.

On our website we recognize all past donations made in memory of friends and loved ones.

Awakening Spring inThickson’s Woods
by Carol Horner

The sun is shining, the sky is blue and the air is warm with the promise of spring. The birds are calling me.

At Thickson’s Woods it‘s quiet. A few people are out enjoying a fine spring day, but the crowds of spring birders have yet to arrive. Migration is, however, already well under way and there is a juxtaposition of new spring arrivals and remaining wintering birds. Over the meadow tree swallows chatter quietly as they hawk for tiny insects. Song sparrows sing from several locations, their song a constant accompaniment as I enjoy my walk. Red-winged blackbirds call from the marsh, where they are already defending territory.

In the woods a winter wren dives for cover in a brush pile as I approach, scolding me with its rattling call. Two brown creepers work their way up adjacent tree trunks. Soon they fall silently from the tree like autumn leaves, landing at the bottom of the next trunk, where they once again begin their ascent. From high above I hear a northern cardinal singing his heart out, "pretty, pretty, pretty," and his mate answers him from the forest floor with her sharp chip note. A white-breasted nuthatch calls softly nearby. I hear the gentle tapping of a woodpecker and look to see if it will be my first yellow-bellied sapsucker of the season. It’s not, and I content myself to watch the male downy woodpecker, his plumage fresh and bright, as he forages for food.

It is, however, the golden-crowned kinglets that capture my imagination today. The tiny birds dance about in the branches, never alighting for more than a few seconds. Their high-pitched quiet call seems to come from everywhere around me at once as I try to hold them in my binoculars, and maybe even get a photo. Their brilliantly coloured crowns steal the sunlight, then return it in flashes of orange, red and yellow. Their energy is endless, their movement constant.

Spring migration is progressing predictably. Tree sparrows and dark-eyed juncos continue to come to the seed that has been left out near the entrance to the woods, but soon it will be their turn to head north to their breeding territories. The sapsuckers will be here any day now, and then others will follow in droves. Soon we will be enjoying the thrushes, sparrows, warblers, tanagers, orioles and grosbeaks once again, and hoping for a rarity, perhaps a Kentucky warbler.

Today is April 9th. One month from now we will be at the peak of migration and Thickson’s Woods will welcome hordes of migrant songbirds, and with them the annual migration of birders as they emerge from winter hibernation and head for the woods, binoculars slung around their necks and smiles on their faces.

Carol Horner is a valued member of the Thickson’s Woods Land Trust board of directors. We’re very glad she volunteered to share her enthusiasm for birding and her unique talents as a writer.

Why not share one of your adventures in nature? Our readers eagerly await. Or if your talents also lie in the artistic arena, send us some sketches for our newsletter.

Maintaining Biodiversity in the Reserve

Thickson’s Woods Nature Reserve has a unique mix of habitats within a very small area, each home to plants and animals specially adapted to thrive there.

Lake Ontario and its shoreline border the reserve to the south. Bank swallows nest in burrows they excavate into veins of sand in the bluff. A pair of kingfishers often nest there as well, using overhanging trees as perches from which to dive for small fish in the shallow waters near shore. Brushy grapevine tangles along the bank are home to nesting song sparrows. Spotted sandpipers perch on emerging rocks near shore or search for food among the pebbles on the beach. Migrating hawks and day-migrating passerines such as blue jays, robins and swallows follow the shoreline westward in fall rather than cross the 50 kilometres of open water to the south.

A short distance offshore flocks of puddle ducks, Canada geese and swans loaf and feed. In deeper water, double-crested cormorants, grebes and loons dive for fish, eagerly awaited as they surface by gulls wanting to steal their catch. Later in autumn, gulls harassing flocks of diving ducks may be joined by passing jaegers, consummate pirates of the bird world.

Corbett Creek Marsh along the eastern margin of the reserve is home to rails and swamp sparrows, monkey flowers and water lilies, muskrats and beavers, carp and catfish. Upstream, the wooded banks of Corbett Creek shelter white-tailed deer and red foxes, green herons and gray catbirds.

North of the Waterfront Trail, portions of the meadow overgrown with nannyberry and dogwood offer nesting sites to yellow warblers and willow flycatchers, and it’s difficult to walk far without startling a cottontail from its hiding place.

The woods itself offers a variety of diverse habitats. Bordering Corbett Creek Marsh and along the seeps that project westward into the woods between a series of ridges, speckled alder and mountain maple predominate, along with other northern specialties such as blue bead lily and star flower. Here northern waterthrushes and rusty blackbirds glean insects off fallen trunks and branches at the water’s edge. But atop the ridges, more southerly species such as black cherry and butternut predominate, while the orange flowers of jewelweed growing in damper hollows are visited by hungry hummingbirds and hummingbird moths.

The sunny valley on the south side of the woods provides a microclimate with lush growth of chokecherry, ostrich fern, and wild grape, the largest of which has grown to the top of a huge yellow birch and is more than ten centimetres in diameter at the base. In winter, white-throated sparrows and dark-eyed juncos forage among the tangles. In May they are replaced by Lincoln’s sparrows, ruby-crowned kinglets, common yellowthroats and a variety of other colourful passerines busily feeding on the abundant midges. No migrant that arrives in Thickson’s Woods in May need leave hungry.

The jewels of the woods are the towering white pines more than thirty metres tall. They provide a critical vertical constituent to the forest that allows pine warblers and great horned owls to live their lives far above the constant comings and goings far below.

Thickson’s Wood Nature Reserve is home to close to 400 species of vascular plants, as well as a great variety of mushrooms. Nearly thirty species of mammals, close to three hundred species of birds, more than thirty kinds of butterflies, many varieties of dragonflies and damselflies, and a multitude of other insects and spiders either live in the reserve, or have visited here.

One of the greatest threats to biodiversity in the reserve is the proliferation of invasive alien species. Green ash borer has destroyed most of the ash trees in southwestern Ontario, and they’re moving east. Two of the worst invasive plants are garlic mustard and dog-strangling vine. Both are very aggressive, crowding and choking out native plants. Both are extremely adaptable to a variety of soil types, and both will grow in full sun or dense shade, very wet places or very dry areas. Both can be controlled, but vigilance, perseverance and hard work are essential. Many websites provide much more information including excellent photos and control information on garlic mustard and dog-strangling vine.

If we all work together, we can keep Thickson’s Woods Nature Reserve a vibrant beacon of biodiversity to welcome visitors of all species for generations to come.

Dog-strangling Vine
(Pale Swallowwort), an Invasive

Dog-strangling vine has appeared in the meadow. In a couple of spots it has grown undetected among clumps of red-osier dogwood, creating dense mats of small plants where seeds have obviously dropped to the ground over several years. In order to gain access to the patches to dig out the rhizomes, we had to cut back the dogwood. Pulling the stems out does not kill the plant, since the underground stem is really the growth centre. Carefully digging up the plant, shaking the dirt off the rhizome, and letting it dry kills it. Most of the smaller plants can be killed by hoeing them off below the ground. Since the plants are very tiny during the first years of growth, finding isolated individuals is almost impossible until they grow large enough to flower. Blooms are pinkish purple and not particularly showy, although, apparently, those who brought the first ones over from Europe to plant in their flower gardens must have found them attractive.

The plant has shiny, oblong, pointed leaves arranged in opposite pairs. It can grow more than two metres tall when it finds a tree or shrub to climb for support. The growing tip spirals around twigs and other plant material, rather than using tendrils for attachment. Swallowwort is a perennial. Each rhizome increases in size from year to year. Old stems remain and are used by the next year’s plants for support as they climb to reach sunlight.

Removing the portion of each plant that contains the thin pods before they open in late summer will help prevent the spread of seeds on the wind. The vines can be unwound from their supports without loosening the pods. Apparently, monarch butterflies sometimes lay eggs on swallowwort, a relative of milkweed, but the larvae don’t survive. The seeds with their fluffy white parachutes are similar to those of milkweed, thistles, or dandelions. The pods are similar in shape to those on dogbane, but seem a bit larger and fatter.

Garlic Mustard

We’re making great progress in controlling garlic mustard in the woods. Very few plants have survived to produce seeds over the past couple of years. As the residual seed base is reduced, the task of controlling this invasive pest should become more manageable.

The plants are biennial. Seeds germinate in early spring as soon as the ground surface warms a bit. The first two opposite leaflets are one to two centemetres long attached by an almost invisible stalk, so that they seem almost to be floating in space. Later leaves are somewhat heart-shaped with toothed margins. When trampled or squeezed, they give off a garlic scent, hence the name. The tap root has a characteristic bend in it. Some books describe it as "C-shaped." During the first summer, plant size can vary from tiny to large, depending on light, soil conditions and spacing. In a heavily infested area, there can be hundreds or even thousands of individuals per square metre, choking out all other vegetation. Since garlic mustard stays green all winter, it gets a head start on native North American wildflowers that are dormant over the winter, and depend on blooming and producing food before the forest canopy seals out sunlight.

With this advantage, garlic mustard grows quickly, producing tiny, white four-petalled flowers in May. By July the seed pods have dried and opened to drop their tiny, shiny black seeds, and the plants die. One large plant can produce many hundreds of seeds. They are so small that they can be picked up on the muddy feet of animals or humans, or even on vehicle tires, and transported to new locations.

Destroying newly sprouted seedlings can be easily done with a hoe or cultivator or even by brushing them with a gardening glove. For most of the summer, growing seedlings can be hoed out, if they can be found among dense vegetation. Early November, after leaves have fallen, is a good time to dig up any remaining plants. Knock the dirt off the roots and toss them lightly on the ground where winter frosts will kill them.

In early spring, as soon as the ground is thawed, plants can be removed. Use a sturdy trowel or small shovel to uproot them. They need to be destroyed, since they will continue to grow long enough to flower and produce seeds, even if all soil is removed from the roots. Frequent checks throughout May will reveal missed plants that are now flowering. The white blooms stand out as dusk approaches.

With the Best of Intentions...
by Margaret Carney

Owls aren't the only year-round residents of the towering pines of Thickson's Woods. Visitors often spot furry raccoons curled up in hollows or peering down from stubs—sometimes whole families of raccoons. I was surprised to find four babies and their mom climbing about in one of the apple trees in the meadow in June.

Thickson's Woods, a tiny island of green in a sea of development, is being overrun by raccoons, and I know why. Last winter I noticed a van pull in behind the houses on the south side of the woods. The driver climbed down, took out a trap and released a raccoon, which lumbered off toward the nearest pine and started climbing. When questioned, the man said he wasn't able to drive down the north side of the woods, on the Waterfront Trail, as he usually did, because it was covered with snow that day. Clearly, the reserve was his favourite place to release animals he didn't want in his own neighbourhood.

He obviously never considered the possible effect on the reserve, which doesn't have food or space for what? the half dozen? dozen? raccoons he's released there.

People regularly drop off pets they don't want at the bottom of Thickson Road—cats, dogs, once even a ferret. But many wild animals are released as well. Every winter grey squirrels get dropped off by the dozens. Their most detrimental impact—stripping bark off young maples and snipping growing tips off the oaks.

Without thinking of possible consequences, someone we know released a red squirrel in the woods a decade ago. The squirrel must have been pregnant, for there's been a population ever since. It was about ten years ago when wood thrushes last nested in Thickson's Woods—a coincidence, or a result of this well-known nest robber?

A local naturalist released the first opossum in the woods, another known predator of bird eggs. Possums, too, are seen regularly now.

Left alone, nature manages to keep wildlife populations in balance. Enter humans, and a tiny island of green can be overrun and overloaded—and overwhelmed.