Rouge Valley Conservation Centre
Nature Notes
By Steve Gahbauer
March 2009
Nature Reawakens
When does spring really begin? In his reflections on nature (the book Wintergreen) Monte Hummel, president emeritus of WWF-Canada, says “it all begins against the snows of late February when willows start to turn yellowy-ocher, the fine branches of birches show a tinge of dark-red, and dogwoods deepen to a rich burgundy.” The first Skunk-cabbage pokes up through the last remnants of winter snow, soon followed by Coltsfoot and Crocuses. Sharp-lobed Hepaticas tell us that it is early April. Our beautiful Trilliums come out in May, defining woodland flowers. Patches of Mayapple and blue Scilla appear on the edges of woodlots. Bloodroots with their distinctively lobed leaves poke through the leaf litter, and shiny Marsh-marigolds attract newly arriving insects, although they carry no nectar. The ferns are out, and on the south side of the trail leading off the hogback trail toward the high cliff, you may spot the rare Fringed Polygala that I have seen nowhere else in the Rouge.
By late May, most species of spring flowers have appeared. Some are in full flush, some early ones linger, and others build a bridge to summer. Wild Columbines nourish nectar-seeking spring insects and returning Rufous Hummingbirds – the only species that comes to Ontario. Trees and shrubs also blossom to reproduce – and then there are the birds. A billion of them are winging their way northward to the sprawling boreal forest region which supports more birds than any other region on earth – not species, but sheer numbers.
Spring birding often focuses on the small, flashy songbirds that arrive in May: Indigo Buntings, Scarlet Tanagers, Rose-breasted Grosbeaks, and a variety of warblers. But these are the latecomers. The first migrants include waterfowl, such as Tundra Swans, ducks and geese, as well as some raptors – thousands of hawks on a peak day.
From the Great Gray Owl, that rarely ventures beyond its boreal haunts, to the Blackpoll Warbler, that winters in the Amazon Basin, some 240 bird species breed up in Ontario's boreal region, making up an estimated 250 million breeding shorebirds, waterbirds, waterfowl and land birds. For more than half of 89 Ontario species the boreal forest is their breeding ground. That makes them highly dependent on boreal ecosystems and habitats. So why is so much of that area logged and mined? Only 8% of Canada's boreal forest is protected from development; in Ontario it's less than 5%, despite the provincial government's promise years ago to protect a minimum of 12%. And it is not only industrial interests that threaten the boreal region. It has now been discovered that lakes in the forest suffer from “aquatic osteoporosis,” a chemical imbalance caused by declining calcium levels. We need to learn a lesson about squandering our natural capital.
Added to these plights is the fact that migrant neotropical birds, such as the Canada Warbler, spend much more than half of their lives in Central and South America where pesticides and DDT are still being used copiously and get into the food chain. The rapid disappearance of grasslands is also a problem (see Nature Notes of October 2008) and climate change and other habitat losses aggravate the perils of migration flights.
It’s a tough life for our feathered friends.
It’s not only birds that are the harbingers of the long-awaited spring. Other creatures delight us during this period of nature’s reawakening as well. On a sunny day, at the south side of the deer patch east of the railway tracks, close to where the old well is, we may see a vixen taking out her cubs, born in late March, to play outside the fox den and learn how to hunt for voles. Chipmunks begin to scurry around, the raspy “churr” of squirrels echoes in the forest again as they eagerly look for catkins, new shoots and buds, and other old friends in the Rouge Valley are out and about to rediscover the pleasures of spring.
Among them are a number of toads. Despite their squat, warty appearance, there is something appealing about these little critters. Maybe it’s the fact that they eat large quantities of even more unattractive visitors, such as cutworms and earwigs. In addition to the five “true” toad species (genus bufo) we have in Canada, there are also two Canadian species of spadefoot toads. They have a sharp edge on their hind feet that allows them to burrow into loose soil where they like to spend most of the day, hiding from the heat and keeping moist.
Salamanders are perhaps the most elusive of the amphibians, but you can see them during spring breeding. They outnumber all other vertebrates that inhabit our forest areas, and there are more salamander species in Ontario than in any other province or territory in Canada – 11 of them. Recently, two species have been added to Ontario's salamander list: the Northern Dusky Salamander (1989) and the Allegheny Mountain Dusky Salamander (2009). This abundance reflects Ontario's proximity to the place from which salamanders first emerged: the southern Appalachian mountains.
Salamanders share a common ancestry with frogs and toads. Larvae or tadpoles first breath through gills and later, as adults, through lungs. But they must remain moist and avoid prolonged exposure to open air. That’s why they burrow into loose forest soil, hide beneath leaf litter, logs or rocks, and emerge only on rainy nights. Salamanders are unable to regulate their body temperatures and, because their skin is permeable, they are extremely susceptible to changes in environmental conditions.
Among fish, we are delighted to still see some Redside Dace, a small, pretty minnow found in shallow streams, marked by two stripes on its sides: a vivid blaze of neon red that runs from its head to its dorsel fin and a yellow line that goes to its tail. The 12 cm long cyprinid has a protruding lower jaw that allows it to capture small insects from the water’s surface and from the air when it leaps out of the water. The species is still relatively abundant in the U.S. but its range is becoming increasingly discontinuous. It’s Ontario population is now completely isolated and found only in a handful of small streams in the southern part of the province. Redside Dace are being monitored in tributaries of the Rouge by Citizen Scientists volunteers and the Toronto and Region Conservation Authority. The primary threat to the Redside Dace is urbanization.
Afterthoughts...
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-In February, a Red-necked Grebe was spotted at the Scarborough Bluffs. Its tail feathers were missing but otherwise it appeared to be okay. It’s a rare occurrence for this species at that time of year, but birds are tough creatures and keep surprising us.
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-Studies show that the Canada Warbler population is in steep decline since 1972. Despite its name, this bird spends very little time in Canada, arriving in late May and leaving again already before the end of August for its wintering ground in South America's Andean forest at elevations of 1,000 – 2,000 m. Passing through almost a dozen countries during its migration, it picks up a lot of pesticide-contaminated food. The same is true for the Yellow-bellied Flycatcher that spends only about 80 days of the year in Canada. On the other extreme is the Fox Sparrow; it spends about 210 days of its annual cycle here.
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It is very difficult to figure out what birds do during migration. Individuals are often relatively conspicuous during the breeding season, but in migration, patterns related to daily time tables and the use of space are much more obscure. How long do they remain in one place before pushing on? During their stopover, do they faithfully occupy one or more places, or do they wander? When they take off at night, is it always to head on to the next stopover, or is it to select a better spot nearby for continued refueling?
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Last fall, researchers set out to answer these questions by using radio telemetry. They placed multiple antennas on fixed towers in three locations around the Long Point Bird Observatory in southern Ontario and downloaded all signals received from bird-mounted transmitters into a computer database. The analysis – still in progress – will yield much valuable information. Aside from answering some of the questions above, information about stopover ecology also has conservation significance. According to Alex Mills, bird population research in the past two decades shows that migration periods are extremely important for population dynamics. Many species spend more time each year migrating than they do holding breeding territories. And songbird mortality is greater during migration than at any other time. This new research will shed some light on these phenomena.
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Another new twist in using satellite telemetry is the deployment of geolocaters now being pioneered by York University research chair in biology and conservation, Dr. Bridget Stutchbury. Bird-mounted geolocaters detect light and tell the time of sunrise and sunset, thus pinpointing the location of a migrating bird. The study involves Wood Thrushes, who fly to Honduras for the winter, and Purple Martins, who migrate to Brazil. The fall migration takes an average of 45 days with stopovers; the spring return migration is usually accomplished in 13 days.
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-Another research project starting this spring is the Frontenac Bird Study, a long-term initiative for the study and protection of birds in the Frontenac Arch, the billion-year-old “backbone” of eastern North America and a region of outstanding ecological significance. It is a vital habitat corridor for migration and a critical nursery for many of Ontario's disappearing fauna and flora. Planning is well underway for this multifaceted project. It will blend scientific research and monitoring with education and outreach programs to gain increased knowledge of avian populations and ecology; establish a tracking system for changes in avian communities; and raise awareness of the ecological significance of the Frontenac Arch. This work will be carried out in collaboration with other conservation agencies by the Migration Research Foundation (MRF) established in 2002 by Marcel Gahbauer to support conservation and wildlife management efforts through improving our knowledge of animal distribution and movement. Past and present MRF projects include research programs on Peregrine Falcons, Swainson's Hawks, Arctic predators, Short-eared Owls and Saw-whet Owls.
Nature happenings during the period covered by this article include:
The return of Eastern Phoebes, Eastern Towhees, Fox Sparrows, Snipe and Tree Swallows in April. Later migrants include Brown Thrashers, Pine Warblers, Palm Warblers, Chimney Swifts, Chipping Sparrows, Barn Swallows and Caspian Terns. Great Horned Owls have their young, hummingbirds and orioles arrive in early May, and Common Loons finish their northward migration. Purple Martin scouts arrive in mid-April, followed by the rest of the flock a little later. Cardinals begin nesting, White-throated Sparrows start calling, and Eastern Bluebirds are breeding.
If you have had a rough day and need to recharge, there is no better way than a healthy dose of peace, beauty and solitude that nature can provide. You can find it during a walk in the Rouge Valley. Happy hiking until I’ll be back again with summer nature notes in June.
Sources: Wintergreen, Ontario Nature, Bird Studies Canada, Migration Research Foundation, personal field notes.
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