Long Point Bird Observatory 2016 Year End Report

The first Barred Owl (Strix varia) ever banded at Long Point Bird Observatory was captured in 2016.

Photo: Terren (Wikimedia Commons)

In 2016 Long Point Bird Observatory (LPBO), the oldest bird observatory in the western hemisphere, completed its 58th migration monitoring season. LBPO banded 44,612 birds last year. Additionally 5,419 recaptures of previously banded birds were processed. The first Barred Owl ever banded at LPBO was captured during the fall season. Other notable banding records included the eighth ever Broad-winged Hawk (the first since 2006), the fourth ever Painted Bunting and record high banding totals for:

· Cliff Swallow, 22 (previous record was 13 in 1982);
· Oregon Junco, three (single birds banded in six previous years)
· Red-eyed Vireo, 496 (previous record was 490 in 2012);
· Summer Tanager, four (tied with 2009);
· Tufted Titmouse, five (previous record was four in 2005);
· Warbling Vireo, 162 (previous record was 143 in 2014); and
· Yellow Palm Warbler, six (tied with 2005).

Despite these highlights, LPBO banded the fewest birds since 2004. Last year, LPBO banded 15.5% (4,498 individuals) fewer birds than the previous 10-year average. The story was no better for the number of species and forms, with 2016 again being the lowest total since 2004. The 141 species and forms captured in 2016 was about 10% (16 species) below the previous 10-year average.

The complete 2016 Year End Report can be found here.

Naturescape: Early Morning at Gravelly Bay

Day breaks over Gravely Bay on Long Point, Ontario. The life of a professional ornithologist is punctuated by amazing sunrises on an almost daily basis.

Photo: Mark Conboy

Naturescape: Amherst Island

A gloomy winter's day on Amherst Island, Lake Ontario.

Photo: Mark Conboy

Lake Erie's Hidden Hydrocarbons

Beneath Lake Erie is a wealth of oil and natural gas, giving rise to an industry that many local people don't realize exists in their own backyards.

Photo: Mark Conboy

I came to live on Lake Erie a year and half ago. After a term as an environmental consultant working on various oil and gas developments in Alberta, I decided that an industrial job and big city life weren't ideal, so I said goodbye to the boreal forest, the Rocky Mountains, the great spreading plains, and moved east, far from the oil and gas heartland. But I was very soon to realize that Lake Erie, was in fact an oil and gas hub all its own.

Now, this wasn't a total surprise, but it was something I hadn't really considered. I knew, of course, that Canada's first hydrocarbon company had been established to make asphalt from near-surface tar deposits at Petrolia, Ontario. By 1858, the first true oil wells in all of North America were dug in southern Ontario near the town of Oil Springs (it wasn't until the following year that the American oil crazy took off when Edwin Drake famously drilled into a pressured reservoir at Oil Creek, Pennsylvania). The sight of oil pumpjacks and natural gas well heads spread out across the countryside was nothing new to me either. But, I admittedly got a big surprise when I unfolded a nautical chart of Long Point Bay, and saw the maze of pipelines which crisscrossed the lake bed, connecting dozens of gas wells. It had never occurred to me, that there was an offshore hydrocarbon industry on the Great Lakes. Then again, why shouldn't there be? Offshore ocean oil and gas industries exist all over the world, and with oil and gas deposits to the north and south of Lake Erie, it should have been obvious.

But the offshore oil and gas industry on Lake Erie isn't obvious. There are no permanent oil platforms. Natural gas drilling rigs are modest-sized barges that only take a week or so to dig a well and bring it into production, so their presence on the lake is not all that intrusive. Well heads and pipelines lay on the bottom of the lake, completely out of sight, aside from the small white buoys that mark their presence. Indeed, many people who live on Lake Erie have no idea that an offshore oil and gas industry exists.

There are close to 500 natural gas wells (and far fewer oil wells) currently in operation on the Canadian side of Lake Erie, though several thousand have been drilled since production began in 1913. In fact, almost the entire offshore oil and gas industry is based on the Canadian side of the Great Lakes. The only state which currently allows offshore production is Michigan, but all of the wells under Lake Michigan are drilled from shore. In Ontario, oil is harvested from Lake Erie using the same kind of shore-based technique, called directional drilling. This involves drilling vertically to desired depth, then drilling horizontally under the lake bed, sometimes for many kilometres, through the oil-containing rock formation. Once a well is operational, the oil is pumped directly back to shore. In this way, the risk of an oil spill is kept to an absolute minimum. Typical drilling for natural gas uses another approach. In this case specialized barges drill vertically into the lake bed. Once the drilling is done, the well is capped and connected to shore via a pipeline. There are some 890 km of pipelines in operation under Lake Erie today. Some directional drilling may be employed for natural gas as well, but given the reduced environmental contamination risks of natural gas, most drilling can safely occur offshore. Most wells are expected to produce for 10-20 years.

Major oil and natural gas pipelines in Lake Erie.

Map: Offshore Magazine

Lake Erie oil and gas is extracted from Silurian aged rocks, 419-444 million years old. When these rocks formed, Ontario was a very different place. The province was located some 6000 kilometres south, at approximately the same latitude where Bolivia sits today. Though having the enviable geography of a tropical paradise, Silurian Ontario would have been amazingly devoid of terrestrial life, because it would still be another few hundred million years before land plants and animals became abundant. Silurian ocean life was plentiful however, with fish diversifying rapidly and microscopic marine algae providing the foundation for food webs, just as it does today. For at least part of the Silurian, southern Ontario was covered by a relatively shallow tropical sea. It was from this sea that Lake Erie's oil and gas deposits arose. Dead organic materials, in this case Silurian marine algae and animals which become buried under layers of sediment are transformed into oil over millions of years through exposure to phenomenally high temperatures and pressures. Over time, exposure to heat and pressure chemically alters the trapped organic material, turning it into oil. In effect, when we use Lake Erie oil for fuel we are essentially burning ancient algal blooms, with perhaps a smattering of fish, sea scorpions, crinoids, mollusks and brachiopods mixed in. Natural gas that is harvested from beneath Lake Erie was formed in the same way oil, but gas can also be formed through the anoxic decomposition of organic matter under much simpler conditions such as in a bog or swamp, and during digestion by animals. Even humans create their fair share of natural gas; natural gas is simply methane, after all.

The Silurian rocks which contain Lake Erie's oil and gas are buried between 100 and 1100 meters below the lake bottom. Two types of natural gas are produced: at the eastern end of the lake sandstones and shales produce sweet gas, or natural gas that doesn't contain poisonous foul-smelling hydrogen sulfide. In the western half of the lake a series of ancient patch reefs, 10-40 metres thick produce sour gas, natural gas which does contain hydrogen sulfide. It's not uncommon for people to picture reservoirs of oil or gas as underground lakes. But that's not the way it is at all, in fact, the oil and gas are within the rocks themselves, filling tiny pores. The sandstones and shales, which are made of compacted and lithified Silurian sand and mud, respectively, are full of pores and those pores are full or oil and gas. The oil and gas didn't form inside those pores, but migrated there from their over long periods of time from its original location. Just as coffee percolates through a filter, oil and gas percolate their way through porous rock formations, some escaping to the surface, some getting trapped under impermeable layers of rock building up in large enough quantities for us to extract it economically. The formation of oil and gas deposits is a surprisingly dynamic process, only it takes place over such extraordinary timescales that it seems static from the typical human perspective. 

Compared to Alberta, Ontario's oil and gas industry is tiny. Virtually all of the production from Lake Erie's oil and gas fields is used in Ontario, but that only amounts to 1% of the province's annual oil consumption and 2% of annual gas consumption. Small potatoes. And thank goodness for that. Because, no matter how carefully an industry is regulated and no matter how much effort is made to reduce the risk of environmentally damaging oil spills, accidents do happen and when they happen in an offshore environment they can devastate ecosystems and be all but impossible to clean up. Spills and leaks seem to be relatively uncommon but they do occur in Lake Erie from time to time. Coming up with exact numbers for recent years isn't easy, but there are always a couple of small incidents annually.

Beyond the problem of oil spills and gas leaks, sedimentation, primarily from drilling waste, is another potential environmental concern. When wells are drilled, tailings in the form of sand, mud, rock particles and drilling fluids are released into the lake, where they can cause localized sedimentation. Whether this is a major problem for wildlife is unclear, but given that less than one hundred new wells are dug in the average year on Lake Erie, it probably is not. Compared to the uncounted tonnes of sand that is carried around the lake naturally by winds, currents and erosion, the harm caused by drilling sediment must surely be negligible, or at least very localized. That being said, drilling fluids do contain chemicals that are known to be harmful to humans, and unfortunately they are released (at least in some cases) directly into the lake; why exactly this is allowed and what health consequences may result is unclear.

Although Alberta (and to a lesser extent British Columbia and Saskatchewan) is the focus of Canada's oil and gas industry, southern Ontario is its birthplace. Lake Erie's small but sustained production has, for better or worse, kept the industry alive in Ontario for more than a century, even if it is relatively unknown.

Sanguivorous Stomoxys

Stable Fly (Stomoxys calcitrans)

Photo: Pavel Krok (Wikimedia Commons)

Biting flies are a fact of life in Canada. From spring snow melt until autumn freeze-up, mosquitoes, deer flies, horse flies, moose flies, snipe flies (Symphoromyia sp.), black flies and no-see-ums (Culicoides sp.) turn forests, wetlands and tundra into buzzing menageries of pain. Oh, how many litres of blood I have donated to the sanguivores of the north! I've lived and worked all over Canada's boreal forest, and the flies there are as bad as can possibly be imagined - actually sometimes they're worse. Presently though, I live in southern Canada, almost as far south as you can go and still be in the Great White North, 700 km from the boreal forest, but even here, on the shores of Lake Erie, the flies still torment me. There are mosquitos, and deer flies, and horse flies, including a particularly large species that I like to call the Darth Vader Fly (Tabanus atratus), but they're nothing like what I'm used to from in north country. Instead, the shores of the Great Lakes harbour yet another villain, one that's every bit as tenacious and often as abundant as its boreal couterparts: the Stable Fly (Stomoxys calcitrans).

Now I've been dealing with Stable Flies all my life, as a minor annoyance on any given fishing or canoe trip. But only recently have I found a place where a normal day in late summer or early fall entails braving swarms of thousands of the little bastards. That place is Long Point, on the north shore of Lake Erie, and I just happen to live there. After spending a summer feeding Stable Flies with generous helping of my blood, I wanted to understand why there are so many flies on Long Point.

Stable Flies are yet another unfortunate addition to the long list of Old World species that have been introduced to North America. That's right, they're not native, so if it wasn't for some damned fool who imported the little monstrosities, we'd be able to enjoy our summers with one less entomological menace. But alas, humans have a particular knack for ruining everything. The Stable Fly likely came to North America in association with livestock as early as the 1700's, and as its name suggests, it's associated with stables, barns, and farms in general. And its on farms that Stable Flies become a serious pest. They are blood suckers, and they can take so much blood from livestock so as to cause anemia, weight loss and reduced milk production. If that wasn't enough, they can potentially transmit lethal diseases like anthrax-causing bacteria, Bacillus anthracis.

Stable Flies are obligate sanguivores, females require not one, but  at least two complete blood meals to produce eggs. Males also bite, something that sets Stable Flies apart from almost all of our other biting flies, in which it's only the females that take blood. Indeed, Stable Flies are oddities within their own family, Muscidae. Most muscids suck up their food using soft, spongy mouthparts, a House Fly (Musca domestica) is a good example. Among our muscids, only the Stable Fly and another livestock pest (that doesn't attack humans), the Horn Fly (Siphona irritans) bite. Stable Fly bites are particularly painful because they don't inject their victims with anesthetic, like mosquitos so courteously do. Feeding primarily on livestock which, other than floppy ears and a whipping tail, have no way to keep the flies at bay, meaning that Stable Flies don't have to exercise subtlety when they bite because there is nothing  their victims can do to stop them anyhow. That's probably also why Stable Flies take their time sucking up blood: it takes about four minutes to consume a complete blood meal.

Thankfully, as anyone who has toiled among Stable Flies will know, these insidious insects fly low, focusing their bloody attacks on the legs and feet, generally sparing the rest of one's body (so dressing appropriately can be a simple and effective defense). But they also, from time to time, fly really high, they've been collected 1 km up and probably go much higher when swept away in weather systems. It's during these high-flying forays that Stable Flies disperse from their breeding sites, the rotting vegetation and manure of active feedlots and barnyards. Rotting vegetation elsewhere, like that which washes up on Great Lakes beaches or in wetlands can also be a source of Stable Flies, but it appears that livestock operations are by far the most important breeding grounds. During these dispersal events, they can form untold concentrations along the shores of the Great Lakes, including literally right in my own backyard. The reason they accumulate specifically along the Great Lakes may have to do with localized weather patterns, lake breezes.

Lake breezes are familiar to all who live on the Great Lakes. It's the lovely wind that blows onshore throughout the day, moderating summer temperatures, and making the intense humidity of July and August bearable. It's a localized phenomenon that can be thought of as a conveyor belt of air swirling above the lake and shoreline. The lake breeze begins as the morning sun heats the land adjacent to the lake. As it warms, air over land rises, often carrying with it a morning flight of Turkey Vultures (Cathartes aura), hawks, and an assortment of insects, including Stable Flies. The warmed, rising air, once it reaches a certain altitude, flows out over the lake. Vultures and hawks can exit the rising air masses at any time, but Stable Flies often remain trapped, so are pulled out over the lake with the flowing air. Now over the lake, the air begins to cool, descending and carrying with it those same flies. The rising air over land causes an area of low pressure to form, so that higher pressure lake air flows towards the shore, filling the low pressure void. This completes the cycle, the air that was once heated over land and that subsequently cooled and descended over the lake, finally flows back toward to shore. Those same Stable Flies, now well-travelled, ride back to the beach on the lake breeze, and there they accumulate.

Stable Flies aren't the only insects that get caught up in lake breeze cycles. Perhaps even more noticeable are lady beetles. I've been inundated at my Lake Erie home with countless thousands of Multicoloured Asian Lady Beetles (Harmonia axyridis). I've seen their colourful little carcasses wash ashore in unbelievable profusion, the ones that didn't make it; and I've seen every piece of driftwood and debris for kilometres of beach covered in the ones that did. Diabrotica sp. beetles also seem to have a propensity for riding the wind. Seldom is it that I can sit on the beach after a swim and don't find at least one Diabrotica sp. nearby. Other species may congregate on beaches too, not brought there by the lake breeze, but instead to feast on the concentrations of Stable Flies. In late summer and autumn, for example, migratory dragonflies, like Common Green Darner (Anax junius), take advantage of the abundance at Long Point. Let them eat their fill I say. By that I mean the dragonflies, not the stable flies!

BioBrevia: Going Deep

Lake Erie's east basin

Map: CHS/NOAA

I live on the north shore of Lake Erie. I watch its water levels rise and fall, its storms rage and subside. I boat hundreds of kilometres on its surface in the course of a year. I watch the migratory birds, butterflies and dragonflies swarm along Long Point every spring and fall. I swim on its wonderful sandy beaches. I'm intrigued by all aspects of Lake's Erie's natural history and geography. To that end, I've enjoyed this set of bathymetry maps from the Canadian Hydrographic Service, the National Oceanic and Atmospheric Administration (NOAA)  National Geophysical Data Center's Marine Geology and Geophysics Division, and the NOAA Great Lakes Environmental Research Laboratory.

In Praise of the Freshwater Drum

Freshwater Drum (Aplodinotus grunniens)

Illustration: WPClipart

I wish to say a few words about an odd fish, the Freshwater Drum (Aplodinotus grunniens). Here's a species that I too seldom see alive, but I do find washed up dead, on the shores of Lake Erie with some regularity. Indeed, just this evening I watched a Great Black-backed Gull (Larus marinus) rip apart a smoldering drum carcass, its heavy bill effortlessly shearing the hard overlapping ctenoid scales that smaller scavengers like Ring-billed Gulls (Larus delawarensis) would have had difficulty penetrating. As fascinating as is the process of death and decay, it's the living Freshwater Drum that I'm here to endorse.

A drum's thick scales help protect it from attack by the parasitic native Silver Lamprey (Ichthyomyzon unicuspis) and the highly invasive non-native Sea Lamprey (Petromyzon marinus). Using suction cup-like mouths, lampreys attach themselves to large fish, chewing through their host's scales to the soft tissue below, using a toothed tongue. A lamprey feeds on the blood of its host, sometimes for months at a time. This can be severely detrimental to the host, resulting in reduced reproductive success, or ultimately even death. Freshwater Drum enjoy the advantage of being a among the most well-armored Great Lakes fish, a significant advantage in a world teaming with raspy-tongued parasites.

Besides their boilerplate scales, drum are oddballs among Great Lakes fish for other reasons, and their name, Freshwater Drum, makes it plain. This is the only species of totally freshwater-dwelling drum. All of the other 160 or so drums and croakers (family Sciaenidae) are marine. No other native Great Lakes fish has such a salty pedigree, though the Burbot (Lota lota) comes close, with only one other member of the cod family (Gadidae) found in freshwater - the Atlantic Tomcod (Microgadus tomcod). The name drum, and the specific moniker grunniens, which means "grunting", refers to the sounds that this species makes during mating, and, indeed, when handled by anglers. Drums don't vocalize in the conventional way most mammals or birds do, by issuing vibrations in the throat, instead their sounds are produced by muscular manipulating of the swim bladder. As far as I know, this is the only Great Lakes fish that makes sounds.

Freshwater Drum eggs contain a large oil globule that allows them to float on the water's surface, something totally unique among North American freshwater fish. Most other freshwater fish lay their eggs in nests, like sticklebacks and sunfish, or  stick their eggs to vegetation or other debris, as Yellow Perch (Perca flavescens) do. Some ichthyologists have suggested that planktonic eggs may be particularly good at dispersing long distances, perhaps having played a role in helping Freshwater Drum to attain the greatest natural latitudinal distribution of any fish in North America; they range from the northern reaches of Manitoba's mighty Nelson River to southern Mexico and Guatemala.

From a simple examination of a fish's mouth, it's possible to hypothesize something about its foraging ecology. For example, a Brook Silverside (Labidesthes sicculus) sports an upturned mouth for taking surface-dwelling prey, and don't forget the aforementioned parasitic lampreys with their suctioning and rasping mouthparts. Silversides and lampreys have highly modified external mouthparts, and while Freshwater Drums have extraordinary internal mouth parts. They're highly adapted for crushing the shells of hard-bodied prey. Most perciform fish have two sets of jaws, the external ones which we can plainly see, and a set of internal ones, and it's a drum's internal ones, the pharyngeal jaws, that set them apart. Drum pharyngeal arches are unique among Great Lakes fish in that they are fused together and are covered with large molar-like teeth, adaptations for processing hard foods, namely mollusks and crayfish. No other fish in the Great Lakes has such highly modified arches, though some other species, like Pumpkinseed (Lepomis gibbosus) and Yellow Perch, do feed on mollusks, they don't have the same crushing adaptations. Drums grind native and non-native mollusks, alike, including Zebra (Dreissena polymorpha) and Quagga Mussels (Dreissena bugensis), on those molar-like teeth using powerful muscles which are supported by a series of bone struts on their robust skulls.

Once in a while, while wandering along the beach, I find a polished and intact drum arch washed up on shore, a reminder that there is a thick-scaled, croaking, planktonic egg-laying, mussel-crushing, freshwater version of a marine fish, beneath the Lake Erie waves. Fascinating!

Cave Swallow Express

Cave Swallow (Petrochelidon fulva)

One of my favourite walking routes is a 5 km stretch of Lake Erie coast, along beaches, over dunes, past wetlands and scrubby bush, which even in December, can produce a good diversity of birds, including fantastic counts of waterfowl. Sometimes, this walk offers up a particularly nice surprise, like the one that came in the form of three Cave Swallows (Petrochelidon fulva), just the other day. Cave Swallows are rare in Ontario, but they do occur nearly every autumn, and the reasons behind their late-season appearance are still a little unclear, but is a probably a combination of factors, including far-ranging weather systems, population ecology and life history traits.

Usually, Cave Swallows begin to appear in Ontario in late October through November, with some birds lingering (or even arriving) as late as December, when the weather allows. Almost all of Ontario's records are from the north shores of Lakes Erie and Ontario, with a few scattered observations elsewhere. Movements into Ontario seem to be almost invariably preceded by strong southerly winds, sometimes in the form of hurricanes and tropical storms, or as more subdued systems which channel warm air out of the southern United States and into the Great Lakes basin. In late fall and even early winter, when southern winds are blowing, it's time to start looking for Cave Swallows. It's not just Ontario that receives these apparent reverse migrations of swallows, the southern Atlantic states, for example, also experience such events.

But why is it the Cave Swallow, of all the possible species, that gets blown north each fall? There are likely a number of factors at work, the first being the phenomenal population increase this species has undergone in Texas since its first breeding record in 1915. Texas's Cave Swallows have increased their breeding range by an estimated 898% since 1957, with concomitant increases in the numbers of both breeding and overwintering birds, particularly in the 1990's. Ontario records may reflect the assent of Cave Swallows, to some degree; the first record of Cave Swallows in Ontario was in 1989, and near-annual autumn movements began in 1998. Species that experience such explosive population growth and range expansion, also seem to be most prone to producing vagrants, in part because young birds may be disperse widely in search of new, less densely populated breeding sites.

There are also life history traits that may mean Cave Swallows are particularly good candidates for vagrancy. Being aerialists, swallows are more likely than other birds, to be sucked into weather systems. Because they are such gifted fliers, Cave Swallows could potentially ride systems longer than other species, which may need to drop out to rest before reaching the Great Lakes. That's not to say that other species don't arrive as vagrants in association with the same kinds of weather patterns that bring the swallows. Currently, there is a western flycatcher (Empidonax sp) in Ohio, and a Vermilion Flycatcher (Pyrocephalus rubinus), a Bullock's Oriole (Icterus bullockii) and a couple of Mountain Bluebirds (Sialia currucoides) in Ontario, plus a Black-throated Grey Warbler (Setophaga nigrescens) in western Quebec. These species could have all been brought north on the same weather systems that have been shuttling Cave Swallows into the Great Lakes basin this fall. Birders should use Cave Swallows as an alert system: when the Cave Swallow Express rolls in, there may other rarities on board.

Two Days with Bruce

Massasauga Rattlesnake (Sistrurus catenatus).

Photo: Mark Conboy

A wrong turn on an unfamiliar trail can lead to confusion, frustration and the unenviable job of backtracking across some slippery talus slope or through a knee-deep swamp. On the other hand, it can also lead to a wonderful discovery. By way of example, I took a wrong turn off a Bruce Peninsula trail earlier this month, and I was rewarded for my buffoonery by an encounter with one of Ontario's least often seen and most misunderstood reptiles: the Massasauga Rattlesnake (Sistrurus catenatus). I went to the Bruce Peninsula specifically in search of rattlesnakes and much to my delight what I found was a land full of additional surprises.

The focus of my explorations was Lion's Head Provincial Nature Reserve, the real treasure of the Bruce Peninsula, with one of most dramatic coastlines on the Great Lakes: shinning white cliffs that support ancient forests of stunted Eastern White Cedars (Thuja occidentalis). The cliffs plunge into a band of forest which in turn sweeps down to the crystalline waters Georgian Bay. Upon the cliff tops themselves, the forest, dense with Eastern White Cedar and Balsam Fir (Abies balsamea), hides a geological wonderland of glacial potholes, acid-worn caves, bottomless crags, overhanging rock faces, and erosion-sculpted boulders of ten thousand different forms.

I started on the trail at six o-clock one evening, into a forest alive with the ethereal whistling of Swainson's Thrushes (Catharus ustulatus), which lent the evening air a subdued and angelic texture. I worked my way east along the ridge top from one spectacular lookout to another. To the north I could see the peninsula stretching far off, a vast swath of seemingly undisturbed forest and coastline. Not a breath of sound, not a light, not a tower, not a road, not a cabin betrayed the illusion of vast and insurmountable wilderness. I knew what truly lay out there, hidden by distance, green forest, and heaving geology. Of course I knew of the towns and cottages, the lighthouses, the roads and their stinking cars. But I let my mind imagine a world unsullied by humans, a wild land stretching from Lion's Head to the tip of the peninsula and beyond to Manitoulan Island, to the North Shore, across the boreal hinterlands, to the freezing waters of Hudson Bay. A world teeming with game and fish and winding trails. The cries of a raven brought me back to reality. And so I lifted my pack, and hit the trail once again.

The cliffs upon which I walked dropped down for ninety or one hundred metres into the forest below. Far from smooth, the cliffs were undercut, overhanging ominously, inviting me to stand upon many a narrow slab, as though to dare fate. The cliff faces were pocked by small depressions and shelves, and it was upon those little natural balconies their existed a most remarkable community of ancient trees, a vertical forest of centuries-old Eastern White Cedars. Many of the cedars, though small and spindly, more like shrubs than proper trees, were two, three, four or even eight centuries old. The oldest yet discovered at Lion's Head is over 1,300 years old and for all its age is only about seven metres tall.

Dolostone cliffs at Lion's Head Provincial Nature Reserve with Eastern White Cedars (Thuja occidentalis).

Photo: Mark Conboy

The cliff-side cedars are natural bonsais, sculpted by centuries of extraordinarily slow growth on water- and nutrient-poor dolostone, twisted by driving winds, polished by blowing snow, and cracked by frost. Their trunks and limbs are gnarled, knotted and ropy. They do look truly ancient, truly sage-like. Many of the cedars appear to be half dead, and indeed they are. Eastern White Cedars, perhaps unique among Ontario trees, grow in sections; one portion of the root mass feeds one portion of the crown. In this way the left side of a cedar may die as the roots which feed it run low on nutrients while the right side of the tree continues to thrive, its roots having managed to find sufficient resources. This segmenting, may be one of the reasons why cedars have such staying power, where other less versatile species simply can't survive. Over the past 10,000 years, fire has periodically burned along the cliff tops, but the cliff faces appear to have been spared, and so the trees were allowed to grow old, excessively old. Even that zealous craze for wood and civilization, the rampant forest clearing, left the difficult-to-access vertical forests unmolested. The longevity of the ancient cedar forests it would seem, is a lucky coincidence of topography: safe there on the cliff sides from the ravages of fire and man. But not entirely safe.

Perhaps the single biggest threat that the ancient cedars face todays is rock climbers. The cliffs of Lion's Head are a popular sport climbing destination. It's easy to spot the most well-climbed routes: lichens have been rubbed away, duff has been swept from the tiny ledges, and in some rare cases, cedar branches have been cut. It seems that most of the pruning, and it hasn't been excessive, was done before the agelessness of the cedars was discovered. Though, if a saw-wielding climber had bothered to look at the annual growth rings of the limbs they were pruning it may have been obvious just how old those trees were. Today, the climbing community has more awareness of the ancient trees, and thankfully, disturbance is less of an issue as it was in the past. To share the cliff faces with age-old trees, that can only add to the exhilaration of the climb, can it not?

Cryptoendolithic organisms (not from the Bruce Peninsula in this example) growing inside a rock.

Photo: Guillaume Dargaud (Wikimedia Commons)

Eastern White Cedar belongs to the family Arborvitae, from the Latin, tree (arbor) of life (vitae). Indeed a fitting appellation for this long-lived species. The cedars though are not the only ancient cliff dwellers. The roughly textured dolostone supports an array of lichens, tiny symbiotic organisms that give colour to the cliff faces. Hidden within the pores of the rocks themselves is even more unlikely and more bizarre life, cryptoendolithic organisms. Nine species of cyanobacteria and 13 species of green algae living 1-5 mm deep within the porous rock have been recorded on the Bruce Peninsula. From the right vantage point these colonies of microorganisms can be seen as black stains on the white dolostone. The cyanobacteria and algae aren't just innocuous cliff dwellers, but instead play a role in the nutrient cycling of the cliff ecosystem, absorbing sunlight through the semi-translucent rock, and imputing nutrients into an otherwise depauperate ecosystem. The Bruce Peninsula is one of only a handful of places on Earth where cryptoendolithic organisms have been studied.
After several kilometres of fairly rugged trail I began a descent towards the coastline past thick slabs of dolostone that fell from the cliffs centuries ago, each now supporting their own garden of trees and shrubs. The Swainson's Thrushes sang all around as I dropped further and further down. Just before reaching the cobble beach, the trail passed below a massive overhanging slab. The slab protruded from the forest like a great bird's beak. Eight metres long and almost as wide, it sheltered a patch of bare soil, starved of rain water and sunshine, nothing grew there, a stark contrast to the thick forests that surrounded the outcrop. It's a fantastic natural sculpture, unexpected along this trail, while simultaneously not out of place in this land of geological wonder.

Earlier on the trail I came across several potholes, including one with the whimsical name, the Giant's Cauldron. These potholes or kettles were formed beneath glacial ice, where free flowing water formed a small whorlpool. Stones gathered up by the whirlpool were spun around and around wearing holes into the rock. The potholes stopped growing when the water flow subsided or the stones that chiselled them eroded to nothing. The Giant's Cauldron was about the size of, well, a very large cauldron, but just down the trail was an even more impressive one, the Lion's Head Pothole. This one was at least three metres deep and about a metre and half in diameter. There was a wonderful little portal in its side, that allowed one to squeeze right inside of the pothole. From within, the smooth stone wall directed your out of a sky light towards a canopy of Sugar Maple (Acer saccharum) and American Beech (Fagus grandifolia). Standing literally within the rock, an eerie silence prevailed.

The Lion's Head Potholes claims another curious naturalist.

Photo: Mark Conboy

The trail stepped over dozens of grykes, joints in the rock widened by weathering of the basic dolostone by slightly acidic rainwater. Small caves peaked out of the leaf litter; I wondered if they led to larger caves, caverns, perhaps as yet unexplored. The trail was rocky and never flat, each step either up or down over pock-marked rock. The pocks, or vugs in geological parlance, were formed as the dolostone itself was formed. Dolostone is essentially limestone that has been infused with magnesium. The original limestone, the precursor to the dolostone I navigated over all evening, was laid down in a massive coral reef sometime during the Silurian period (443 to 416 million years ago). This reef, which essentially forms the backbone of the Niagara Escarpment (of which the Bruce Peninsula is the northernmost extension), was formed by the growth and death of countless generations of corals and other sea creatures whose calcium carbonate shells became consolidated into solid limestone over eons. That limestone was eventually pushed underground where it was infused with highly saline magnesium-rich groundwater. The magnesium replaced the lime, changing the limestone to dolostone. That conversion resulted in some loss of rock volume, and that's how the vugs were formed. Had this dolomitization process not occurred we might not have the dramatic scenery of the Bruce Peninsula we see today. Dolostone, though it can be weathered, as evidenced by the potholes, grykes and caves along the trail, and large piles of talus below the cliffs, is far less resistant to erosion than limestone. Perhaps the limestone would have been eroded millennia ago, leaving a more or less flat shoreline, similar to the Peninsula's western shore. But the dolostone has persisted, giving us the dramatic views and ancient cedar forests of the Lion's Head.

The trail lead to a pleasant campsite under the shade of cedars and Red Maples (Acer rubrum). I pitched my tent near the cobble beach and settled in for a night apart from the rest of humankind.

In the morning, I found myself ascending to the cliff tops once again. Black-throated Green Warblers (Setophaga virens) were singing in profusion; it seemed that I was never out of earshot of one all morning. The woods were simply overrun with those pretty little songsters, but it wasn't long before my attention turned from the birds to the trailside plants. The Bruce Peninsula supports over forty species of orchids, most of which I didn't expect to find the Lion's Head; they are inhabitants of bogs, fens, swamps and alavars - habitats I simply didn't pass through on my hike. But these high and dry cedar woods do support a handful of species, including two biogeographical oddities: Menzies' Rattlesnake Plantain (Goodyera oblongifolia) and Alaska Orchid (Piperia unalascensis).

The tiny flowers of an Alaska Orchid (Piperia unalascensis), a western species with a disjunct Great Lake population.

Photo: Mark Conboy

Both the rattlesnake plantain and the Alaska Orchid are western disjunct species. Both are primarily distributed in western North America, but they can also be found in pockets isolated pockets elsewhere. The Alaska Orchid is the more extreme example of this pattern. Its main distribution extends from southern Alaska to Baja California. Disjunct populations occur on the Great Plains, in eastern Canada and of course, in the Great Lakes Basin. It's likely that Alaska Orchid enjoyed a much broader prehistoric distribution, that linked all of the disjunct populations to the species' main western range. For some reason, the Alaska Orchid's range contracted into the discrete populations we see today. Though less dramatically, the rattlesnake plantain also has a similar  disjunct pattern and probably has a similar biogeographic history. Perhaps it was the presence of such disjunct species that caused American botanist M.L. Fernald in the 1920's, to hypothesize that the Bruce Peninsula was an unglaciated relict, harbouring species that once enjoyed a wide preglacial distribution in an ice-free refugium. We now know that unequivically, the Peninsula was completely ice-covered for several thousand years and that the disjunct distribution of orchids and other species must be explained by other means.

Another plant caught my attention on several occasions throughout the hike. The Northern Holly Fern (Polystichum lonchitis) is a relatively rare species in Ontario, but evidently there is a healthy population on the Bruce Peninsula. Beyond ancient trees, disjunct orchids, and unusual ferns, the Bruce Peninsula harbours other botanical treasures, including significant concentrations of range-restricted Dwarf Lake Iris (Iris lacustris), Lakeside Daisy (Hymenoxys herbacea), and Tuberous Indian-plantain (Arnoglossum plantagineum).

Northern Holly Fern (Polystichum lonchitis) and Maidenhair Spleenwort (Asplenium trichomanes).

Photo: Mark Conboy

But as I said, the Massasauga Rattlesnake was the main reason I visited the Bruce Peninsula. Rattlesnakes were extirpated from my home county of Norfolk and most of the rest of Southwestern Ontario long ago, although there are remnant isolated populations at either end of Lake Erie. The species' last true haven is the Bruce Peninsula and the Georgian Bay coast. In the case of Ontario's Massasauga Rattlesnakes, there is a significant amount of genetic differentiation and geographical isolation between the Bruce Peninsula and Georgian Bay populations. Even though these two rattlesnake populations exist in close proximity, they are actually rather isolated from one another, and that can have some important biological consequences. 

Gene flow is important to maintaining genetic diversity, and good genetic diversity can help with disease resistance and adaptation to changing environmental conditions. Isolated populations of snakes and other organisms tend to have limited genetic diversity because of a lack of immigration from other populations (immigrants bring new genetic materials) and inbreeding.

Massasauga Rattlesnake (Sistrurus catenatus).

Photo: Mark Conboy

The snakes of the Bruce Peninsula are isolated from those of eastern Georgian Bay by water (and also intensive agriculture and road development on the southern part of the peninsula). Massasaugas, despite their fondness for wetlands, are unable or unwilling to undertake long distance swims, so the Bruce Peninsula snakes are effectively stuck on their own island, separate from their conspecifics to the east. Indeed open water is such an effective barrier to rattlesnake dispersal that Lyal Island, a mere 1.3 km off the western shore of the Bruce Peninsula, harbours its own genetically distinct population of Massasaugas. At some time in the past, Masassaugas colonized the island, but since that time, emigration from the main peninsula population has been all but nonexistent, allowing the Lyal Island snakes to develop their own genetic identities, apart from the Bruce Peninsula snakes.

 

Isolated populations are not necessarily a bad thing, especially if they are large, and genetic diversity can be maintained to some degree through mutations; so the Bruce Peninsula rattlesnakes are not likely to disappear because of inbreeding or something like that, at least not any time soon. What is most interesting about the isolation and genetic uniqueness of the peninsula's rattlesnakes (and it's orchids too, no doubt), is that it demonstrates a simple biological fact: not all members of one species are the same. I argue that each and every distinctive population should be conserved as though it were a distinctive species. In the case of Massasauga Rattlesnakes, we need to insure that the Bruce Peninsula population is receives proper conservation, and so too does the Lyal Island population and the many genetically discrete populations on Georgian Bay's east coast, each as though they were a different species. It would certainly be a tall order, but it would be the right conservation approach.