Our party of two had a great outing to this urban park. It is closer than Leslie Street Spit, with a lot less walking and some really good wetland and lakeshore habitats. Our first bird of interest was a Gray Catbird near a small pond. On the pond shore we also saw a young Black-crowned Night Heron and some Shoveler and Gadwall. Up ahead a Hooded Merganser caught our eye. On the lake were many ducks and grebes, and we had excellent views of a nice male Harlequin Duck! On our way back we saw many signs of Beaver (we had already seen a Muskrat swimming) and then we saw a Northern Mockingbird that has been residing in the area for some time, according to local birders. I hope we can return with more club members in future.
There is little doubt that the winter solstice of 2013 will be one to remember for a long time to come. The situation was certainly not unprecedented for some freezing rain occurs in most winters. And the amount of rain that fell was less than that that which happened in the great ice storm of 1998 in Ontario. Yet the extent of area that was impacted and the number of people affected in 2013 might well be much greater. More time will be required for a proper assessment of the effects to be completed but the following is a preliminary set of observations from our area.
Fig.1 – Map of precipitation pattern in Ontario for December 20, 2013 from CBC News
The storm was not a single event but two similar storms that followed the same track about two days apart. As it turns out, our area fell zone where the ambient temperatures were too low for the precipitation to fall as rain and too warm to fall as snow. As measured at the Pearson Airport, the amount of rain that fell on December 20 was 8.6 mm followed by 16.6 mm and 13.6 mm on the two days following respectively for a total of 38.8 mm. The distribution of the rainfall as shown in the attached map obtained from the CBC weather forecast indicates that the highest amount of rain was expected further west of Toronto so it would not be unreasonable to expect that we experienced well over 40mm. By comparison, the amount of rain reported during the 1998 storm was 85 mm in Ottawa, 73 mm in Kingston, 108 in Cornwall and 100 mm in Montreal.
Fig. 2. Woods with ice damage, Nassagaweya-Esquesing Line north of Sideroad 15
The net result was an accumulation of a thick layer of ice on all exposed surfaces. The thickness on tree branches was observed to be at least 30 mm on the upper side surfaces. Considering the possibility of dripping, three dimensional distribution and multiple of layers branches, it is conceivable that the true amount of rain here was perhaps double that measured at Toronto. It appeared that the amount of damage above the Niagara Escarpment was greater than that at lower elevations.
The ice that accumulated resulted in a huge weight stresses on the tree branches. Although many factors are involved, the stress resulted in a great amount of branch breakage. It was estimated that about a quarter of the tree canopy in Toronto was damaged by the ice. Falling branches caused extensive damage to power lines and many support poles were broken. It took up to ten days to get all power restored. Fallen branches also blocked sections of roadways.
Fig. 3. Ice damage to willows, Dublin Line.
There are additional factors to consider including species involved and branching patterns of individual trees but two patterns were evident in the breakage. Large branches that broke were often suffering from some previous damage or decay, especially when the branch crotches were narrow. The second thing was the there were huge numbers of smaller branches that were broken, usually in the upper crown. The branches affected exhibited a reasonable consistency in diameter where the break occurred. This was at branch diameters of 6 to 10 cm. It seems reasonable to conclude that the wood strength at diameters greater than this were able to support the load of ice. At lower diameters, the individual twigs were flexible enough to withstand the ice. But at the indicated diameters, the branches supported a certain combination of number of twigs of a particular length such that the critical load-bearing strength of the supporting branch was exceeded and so it broke. A very similar pattern was evident in Eastern Ontario following the storm of 1998. When trees did not break, the trunks bent under the load. In some cases, species such as poplars and birch bent to a high degree, sometimes involving trunk diameters that were well in excess of what one might expect as possible.
Despite the obvious damage, especially where entire trees had to be removed, the long-term impact likely to be limited. Broken branches will undoubtedly reduce the rate of growth of the trees for a short period of time. It is to be expected that broken branches will create potential infection courts for decay to become established. Studies of this kind were initiated following the storm of 1998 but the results of those studies have not been widely distributed. When one travels through eastern Ontario, it is becoming increasingly difficult to see broken branches as the branches lower on the trunk have grown and surpassed the point of the break.
While we cannot say with certainty that a similar storm will or will not occur again in the near future, the possibility for such a storm will always remain. While it may be counter intuitive that an ice storm resulted from global warming, that may in fact be the case. Global warming is expected to alter the frequency and severity of storms but storms can occur in all seasons. It will not be possible to attribute any individual storm to climate change. All we will be able to do is observe that more storms occur and deal with them as they arise.
The situation regarding invasive species is never static. Periodically we get good news mixed in with the gloomy reports of some new species that has appeared at our door. And so it is that we have some recent changes in local matters pertaining to invasive alien species.
Starting with the bad news first, the Asian Longhorn Beetle (Anoplophora glabripennis) which attacks a wide range of tree hosts had been declared eradicated from the Cities of Toronto and Vaughn. By 2003, the beetle had established a modest area of infestation in the boundary area between those municipalities. An intensive program was launched to eliminate the infestation by cutting and destroying all of the host trees within a 400 metre radius of the infestation. After detailed surveys of the area had found no more indications of the beetle for a period of five years, the pest was declared eradicated by the Canadian Food Inspection Agency (CFIA) on April 5, 2013. Unfortunately, a new infestation was detected in an industrial area on American Drive near Pearson International Airport in Mississauga on September 20, 2013. It is not known if the two areas of infestation are connected. They are not located too far apart so a connection cannot be ruled out though a new source of infestation is presumed. Multiple points of infestation are known at other locations in North America where similar eradication programs had been carried out. Some trees have already been cut down and it is expected that a similar form of eradication program will be undertaken to insure that the beetles do not spread.
Figure 2. Larva of Hypena opulenta
On August 23, 2013, Credit Valley Conservation (CVC) reported that two round gobies (Neogobius melanostomus) were caught in the west Credit River at Hillsburgh. Additional surveys found at least 50 more of the fish just downstream. Previously, the species had been found only at sites in the catchment area where the water was closely connected to Lake Ontario, a location where the species has become well – established. It seems improbable that the fish had made it to Hillsburgh across dams and other obstacles without some sort of human intervention, whether intentionally or unintentionally. A program to manage the problem species needs to be developed in concert with MNR, CVC, local land owners and other stakeholders.
Not all news concerning invasive species is bad. In 2006, moth larvae were found feeding on swallow-worts in southern Ukraine. The larvae were brought to the Commonwealth Agricultural Bureau International (CABI), a highly recognized facility that studies biological control agents, in Switzerland for rearing and initial testing. The moths were found to be host-specific and very effective in controlling the host plant. Additional testing was done at the control facility at the University of Rhode Island to verify the results. The tests were so successful that the University petitioned the U.S. Department of Agriculture in 2012 to allow for the release of the moth to control the Swallow-wort problem. The US still requires one additional step before approval is granted but that approval appears to be easily achievable (after the current political financial situation is resolved in that country). The application though has met all of the conditions set by Canada concerning the release of a biological control agent. As a result, 500 of the moth larvae were released at infested sites near Ottawa. So far, the caterpillars appear to be surviving well and the populations are being monitored. In time, it is not unreasonable to expect to see the moths make their way to our area. While there are many areas in the Province where Swallow-worts are a problem, there are many places around Toronto (e.g. Don River Valley) where the populations are very dense. The moth is known as Hypena opulenta (Figure 10). It resembles a few other Hypena species that occur in our area; however, those other species do not feed on Swallow-wort. This similarity and any resulting confusion may hinder the monitoring of the spread of the species into our area but the presence of the distinctive caterpillars (Figure 2) feeding on the plants should be easy enough. Naturalists should be on the lookout for these caterpillars wherever the Swallow-wort is present though it may take several years to reach here on its own.
Our landscape is networked by roads – ribbons of death where myriad animals from butterflies to deer meet their demise. And though morbid, an objective look at this mortality can provide insight into changing animal populations.
In the 1960’s and 70’s groundhogs, aka woodchucks, were among the most frequent victims of vehicular faunacide. Their bodies littered roadsides as raccoon carcasses do today.
Groundhogs are now rare road-kill victims. No, they haven’t evolved the ability to look both ways before crossing. Rather, the lack of road killed groundhogs suggests that their population has fallen off an ecological cliff.
When I was young, groundhogs – when not playing Russian roulette with cars – stood sentinel in meadows. Boys with 22’s shot them, with the approval of landowners who reviled groundhogs as varmints – diggers of holes that could snap the leg bones of cattle and horses.
I didn’t wield a rifle as a child, but I would sit patiently beside groundhog burrows, waiting for the myopic mammals to poke their heads above ground and sniff the air for predators.
I enjoyed these close interactions with groundhogs and imagined that First Nation’s hunters may have used this technique – crouching like polar bears at the breathing holes of seals – to capture the plump rodents.
So what happened to the groundhogs? Well, certainly their population has been reduced by the aforementioned road – kill, but it is likely no coincidence that the fall corresponded with a rise in coyote numbers.
In southern Ontario and throughout much of North America, coyotes have flourished in recent decades, assuming the role of top predator, filling the void left by the disappearance of wolves.
If a 12 year old boy can approach a groundhog near enough to see its whiskers twitch, consider how easy this would be for a coyote – with predictably unpleasant consequences for the groundhog.
They weigh about as much as a paper clip. Dew worms dwarf them. They are, by weight, the smallest vertebrates in Ontario. But what they lack in size they more than make up in numbers. Red-backed salamanders are abundant, outnumbering all of the reptiles, rodents and birds that share their forest habitat. Densities of red-backed salamanders have been estimated as 500 to 9000 per hectare of woodland!
For several years I took part in a salamander monitoring project at Forks of the Credit Provincial Park. Boards were placed on the forest floor to provide cover for salamanders. Particularly bountiful monthly counts would yield upwards of 70 red-backed salamanders hiding under the boards.
Almost all amphibians need to lay eggs in water. Not so the red-backs. They have escaped the surly bonds of aquatic existence. Females lay small grape-like clusters of eggs, under stones or suspended in the cavities of rotting logs.
Freed from the necessity to remain close to ponds, red-backs can disperse to occupy the entirety of the available habitat in woodlands. Laying eggs sans aqua also allows their larvae to avoid becoming lunch for ravenous pond-dwelling predators like dragonfly nymphs and diving beetles.
Of interest as well is that red-backs are lungless, drawing oxygen through the skin. For this to work the skin must be moist, so during the day the salamanders stay out of sight under forest debris. In especially dry weather, and during the winter, they retreat underground.
Many populations of red-backed salamanders are now completely separated from each other. Creatures with legs smaller than carpet tacks cannot readily cross roads and farm fields. Isolation drives the creation of new species. In a few millennia or so, future herpetologists – reptile and amphibian biologists- may have their hands full, cataloguing a diversity of red-backed salamander descendants.
On my way home from our last meeting, with coyotes in mind, I was on the lookout for mammals and eyeshine in my car headlights. In the ten-minute drive, I spotted six domestic cats in fields and along the roadsides. These were the only mammals I saw that night.
So, what impact do our cats have on wildlife if they are allowed to roam free? A recent study in the USA (based on a systematic review and quantitative mortality estimates) found that free-ranging domestic cats kill 1.4 to 3.7 billion birds and 6.9 to 20.7 billion mammals annually (Loss et al., 2013). This means that free-ranging cats are the single greatest source of human-caused mortality for wild birds and mammals. The authors found that feral (including barn) cats caused more damage than owned pets, but many dearly-loved felines spend time in the great outdoors happily hunting. Native species make up the majority of birds and mammals killed by cats, only a few non- native birds are impacted. Free-ranging cats on islands have caused or contributed to 33 recent extinctions, as recorded by the IUCN.
Of course, the cats that do not impact wild populations of songbirds and small mammals are the ones that are kept indoors! Indoor cats are safe from predators such as coyotes and owls. They are less likely to get fleas or other parasites, and they can live a long and happy life without decimating our fragile fauna. Or, take them out on a leash! The photo below by club member Jeff Normandeau shows how content cats can be on a leash.
Cats are funny, smart, loveable, affectionate, and they are cold-blooded killers. They are not native to North America. Unlike most carnivores, they hunt by day or by night. If roving gangs of children were killing thousands of songbirds, would we not hold their parents accountable? Why then do we not hold pet owners accountable for the actions of their pets?
Please, keep your cats indoors and get them spayed. They will live longer and so will your neighborhood birds and small mammals.
The eastern migratory population of monarch butterflies is no more. Lepidopterists (butterfly and moth scientists) confirmed earlier this year, that the once familiar orange and black butterflies are essentially extinct. Their awe-inspiring north-south migrations, linking Mexico, the United States and Canada have ceased.
Most of us are old enough to remember when monarchs were a frequent sight in meadows and gardens. The monarchs’ demise was not unexpected. For decades, people in all three North American countries ratcheted up their assaults on these iconic insects. The monarchs’ overwintering sites in the oyamel fir forests of Trans-volcanic Mountains of central Mexico, while nominally protected, were steadily reduced in size by illegal logging.
Criminal gangs with the tacit assent of corrupt government officials plundered the forests under the cover of darkness.
At the same time, land use practices in North America conspired to reduce milkweed, the monarchs’ larval food plant. Round Up, a potent herbicide was sprayed on thousands of hectares of genetically altered “Round-up Ready” corn and soy, eliminating all of the milkweed in and around agricultural fields.
Homeowners throughout North America could have extended a helping hand by growing milkweed for monarch caterpillars and offering flowers with abundant nectar to the adults. Most people however, in thrall to their lawns, continued to primp and preen those biological wastelands at the expense of birds, butterflies and bugs.
The monarch is dead. No longer will it startle with its beauty. No longer will it inspire with its improbable journey from Canada to Mexico. And no longer will the imaginations of children be carried aloft on its gossamer wings.
Postscript:
In 2006 at a monarch overwintering roost in Mexico I met Lincoln Brower, a pre-eminent monarch butterfly researcher from the United States. He predicted that the eastern North American monarch – our monarch – had “about twenty years left”. I fervently hope he was wrong, but with populations this year at their lowest ebb ever, his dismal forecast may come true.
Ontario is home to five species of rabbits and hares. These include the Arctic Hare (Lepus arcticus), White-tailed Jack Rabbit (Lepus townsendii), Snowshoe Hare (Lepus americanus), Eastern Cottontail (Sylvilagus floridanus), and the main subject of this report, the European Hare (Lepus europaeus). The first two species do not extend into our area at all. Arctic Hare barely get into the most northern parts of the province while the White-tailed Jack Rabbit is included on the basis of a few records from the Rainy River District. The Snowshoe Hare is our most widespread species in Ontario but we are situated at the southern edge of its range so we do not often encounter it unless we travel a short distance further north. In our area, the species that we are most likely to encounter is the Eastern Cottontail. Their populations go through a cycle of abundance and scarcity. It was seldom if ever encountered by European settlers until the mid-1800s and is regarded by some as a species that has expanded its range into Ontario. Skeletal remains found in a First Nations village in Oxford County prove that the species was here long before the supposed arrival in Ontario in 1868 [MacCrimmon, 1977]. There is little doubt though that after its recent arrival, their populations have dramatically increased as the species spread across all of southern Ontario [Dobbyn, 1994] (Map 1). As well as the five wild species noted above, from time to time, the Domestic Rabbit (Oryctolagus cuniculus), escapes from captivity or is purposely released by owners that no longer wish to keep them as pets. These animals do not persist in the wild for any significant period after they are released.
Map 1. Distribution of European Hare in Southern Ontario (Dobbyn, 1994)
The story of the European Hare is quite well documented [MacCrimmon, 1977]. They were introduced to Ontario just over one hundred years ago although some of that species was introduced some years earlier in the eastern United States. In 1912, Otto Herold, the manager of Bow Park Farm located near Brantford imported seven female and two male hares from Germany. Inevitably, they soon escaped. Their numbers increased and they soon spread in all directions from the Bow Park Farm. It expanded its range to cover most of the area south of the Canadian Shield [Dobbyn, 1994]. The peak populations in Ontario appear to have been reached by about 1950. Later attempts to introduce the species to Thunder Bay and Cochrane areas as a new game species were not successful as the hares could not tolerate the conditions in the north.
In 1921, Howitt [1925] reported quite successful hunting of Jack Rabbits in Beverly Township in Wentworth County about 15 km southeast of Cambridge which was then named Galt. This was only nine years after the Hares had been released.
While the hunting community was happy to have a new game animal, farmers trying to grow grain (e.g. winter wheat,) alfalfa, clover, or orchard crops had to contend with a new pest that damaged their crops, especially during the winter. Wild plants were also consumed by these relatively large animals.
As a youngster growing up on a farm on Mississauga Road, it was fairly commonplace to see these animals in the fields. We viewed these animals, usually referred to as Jack Rabbits, as a normal part of the local fauna and we were generally oblivious to the fact that they were not native. Species such as Groundhogs because of their burrowing and Starlings because they were ‘dirty birds’ were a much greater concern. As well, foxes that occasionally took a turkey from the field were a particular nuisance.
Map 2. Location of European Hare sightings in the GTA since 1987
In 1985, we returned from the North to live in this area. A few years later, I began to include mammal sightings in my records and included observations of the European Hares. While the annual numbers of observations were never large, I had records of the species from 1987 to 1998. The records from the GTA are summarized below and the locations are shown in Map 2. Many of the records were made during travel from Acton to Toronto along the Go Train routes. Since 1998, I have not seen the species. The realization that it had been several years since the last observation prompted this report. While there may be other reasons for the disappearance, it would seem that decline in Hares coincided with the increased populations of Coyotes. A parallel decline in numbers of Groundhogs has also occurred in the same general time period. By contrast, Cottontail populations have continued to go through a cyclical pattern.
The local Conservation Authorities (C.V.C, and Conservation Halton) were consulted to determine what records they had in their databases for European Hares. Most of their records were actually ones that I had contributed. The only recent record for the species was a sighting of a Hare at the Frank Tract in Nassagaweya Township by Bob Curry on June 3, 2003. That makes it ten years since we have had a report of the species for our area.
Acknowledgements
Many thanks are extended to Jacqueline Kiers (C.V.C.) and Brenda van Ryswyk (Conservation Halton) for reviewing their agency records of European Hare.
References Cited
Dobbyn, J. 1994. Atlas of the Mammals of Ontario. Federation of Ontario Naturalists, Don Mills, Ontario. 118 pp.
Howitt, H. 1925. Another Invasion of Canada. Can. Field-Nat. 39: 158-160. MacCrimmon, H.R. 1977. Animals, Man and Change. Alien and Extinct Wildlife of Ontario. McClelland and Stewart Ltd. Toronto. 160 pp.
by W.D. McIlveen
Halton/North Peel Naturalist Club
Where there are abundant sources of food, as is the case well illustrated above, there will be predators. I was amazed when I walked in the woods at night, searching for elusive winter moths, to see spiders on the snow surface at intervals of just a few feet. This was on a mild night (relatively speaking) and their sub-nivean burrows may have been flooded with snow melt.
I discovered that these animals are active all winter, mostly below the snow but also on the surface, and their major food is the snow flea. These spiders seem to have big “boxing gloves” that I thought might help them dig, but they are actually the male’s enlarged palpal tips used for copulation.
People manage their appearance with clothing, jewelry and hair styles to present a particular image of themselves to the world.
Deception is often involved. A muscled, leather-clad, tattooed man may be a powderpuff, but his fearsome exterior projects a formidable – “don’t mess with me!” – presence.
Insects are masters of this bluff. There is a vast array of harmless flies and beetles for example, that have evolved to look like dangerous bees and wasps. This allows them to conduct their business with openness and swagger instead of cowering beneath a leaf or skulking in the undergrowth.
But, like everything in nature, mimicry is complex and nuanced. The viceroy butterfly famously mimics the poisonous monarch butterfly. For years it was assumed that the viceroy was free-loading on the monarch’s distasteful reputation, offering nothing in return.
As is often the case in science, this explanation proved too simple. Research revealed that the viceroy doesn’t taste good either, so the two unrelated species actually reinforce each other’s security.
Snowberry Clearwing Moth
The bumblebee serves as a common model for mimicry. The snowberry clearwing moth (left), unarmed and likely quite tasty, looks like a large bumblebee and no doubt gains some protection from this resemblance.
Some robber flies also look like bumblebees, but their motives extend beyond mere protection, to the sinister. Robber flies mimic the nectar sipping bumblebees to ambush their prey. They loiter around flowers, waiting for pollinators like bees, wasps and flies to sidle up to the floral bar for a drink.
Then they pounce. Imagine the surprise of the victim held firmly in the robber fly’s grasp: “But…but… you’re a bumblebee – you don’t eat meat – lemee go!”
Humans have come lately to the art of deceit. Insects have been practicing it for millions of years.
