Tag Archives: conservation

Volunteers needed for a “Bird Blitz”

male-bobolinkAre you a birder? Are you good at identifying grassland birds by ear?

Credit Valley Conservation (CVC) needs your help on a one-day breeding bird survey or ‘blitz’ of meadow habitat in CVC’s middle and upper watersheds. During the blitz volunteers will gather information on the location, abundance and nature of the habitat that these birds require for breeding.

CVC is looking for people who might want to participate in this one-day event. The Bird Blitz will take place in June, with a 2 hour training session ahead of time. Volunteers will conduct surveys – in teams – from roadsides via a ‘point-count’ method.

If you’re interested in participating in the Bird Blitz, please complete the CVC’s online questionnaire.  This questionnaire will help them set up the best dates for training and staging the event.

If you have any questions, please call Annabel Krupp at CVC, 905.670-1615 x 446

About the Grassland Bird Recovery Program

Local populations of grassland birds are finding it increasingly difficult to locate suitable habitat for breeding, nesting and resting. Species like the Eastern Meadowlark and Bobolink are declining and are now considered provincially at-risk, according to ecologists at Credit Valley Conservation (CVC). In an effort to better understand the issues affecting these species and take action to begin addressing their decline, CVC has instituted a pilot 3 year Grassland Bird Recovery Program.  The program has received funding from the Ontario Ministry of Natural Resources’ Species at Risk Habitat Stewardship Fund.

Public action urgently needed to track White Nose Syndrome in bats

White nose syndrome on bat. Photo by Jeff Normandeau
White nose syndrome on bat. Photo by Jeff Normandeau

January and February are usually peak mortality months for bats suffering from White Nose Syndrome. But the The Canadian Cooperative Wildlife Health Centre (CCWHC), the organization that monitors health and disease in wildlife populations, is barely getting any reports. This could mean that bats aren’t dying or aren’t emerging early from hibernation into the non-stop polar vortex this year. But we all know that’s wishful thinking. The other, more likely option is that people don’t know who to call when they see a bat, and therefore we have no idea how far White Nose Syndrome has spread since last winter.

The CCWHC urgently needs your help. If you see a day-flying, sick or dead bat this winter please report it!

Ontario region: 1-866-673-4781
Other areas: click here

Describe the location as precisely as possible, along with the date that you saw or found the bat, and the bat’s behaviour. If you find a live, injured or unwell bat it can be sent to a local wildlife rehabilitation centre.

For more information on this conservation crisis and how you can help, please visit the Liber Ero blog.

It is 10 p.m. Do you know where your cats are?

by Fiona Reid, President

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.

Monarch Butterfly- RIP 2026

by Don Scallen, Vice-President

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.

Read more by Don Scallen at his blog, Notes from the Wild

Disappearance of European Hare from the GTA

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)
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
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

Death of a tree

Two weeks ago one of my favourite trees was felled by a bulldozer. This tree, on Creditview Rd. in Brampton, was graced with the lovely arching form that only mature elms exhibit.

Before Dutch elm disease ravaged the land this beauty was common. The few remaining mature elms are rare treasures.

The lure of this elm was so powerful that I would include Creditview Road on my route to work simply to see it in the morning. The green and gold cropland surrounding it provided a lovely foil for its iconic form.

The cropland is no more. The soil that gave life to the wheat, the corn and the soybeans has been scraped bare by earth moving equipment. Denuded and sterilized, the land waits sullenly for the homes and strip malls that characterize the inexorable expansion of Brampton.

I knew the destruction of this landscape was imminent. New development announces itself with cheery signs and property stakes. But I harboured hope for the elm. Fencing had been placed around it. I thought – naively it turned out – that “my” elm would be saved.

The elm now lies ingloriously in the mud, its roots ripped from the desolate earth.

I realize that thousands of trees are felled every day in this province to feed various appetites. I realize as well that landowners have certain broad rights to do as they wish with the property they own.

But, perhaps it is time to try to enshrine some protection for trees of character – trees that rate highly for certain features including size, rarity, cultural importance and the admittedly subjective quality of beauty.

The elm will continue to influence the route I take to work. I’ll now avoid the place where it once stood.

by Don Scallen
Vice-President, Halton/North Peel Naturalist Club

Tufa deposits discovered in Credit River watershed

Belfountain CA Tufa Deposit (Photo by Lynda Ruegg)
Belfountain CA Tufa Deposit (Photo by Lynda Ruegg)

In 2012, Credit Valley Conservation inventory staff discovered a provincially and nationally rare phenomenon along the Niagara Escarpment at Silver Creek and Belfountain. This discovery was of tufa, a soft rock, being actively formed at the emergence of select springs. Tufa is a variety of limestone. It differs from typical Escarpment rock formed on ancient sea beds from calcium-rich shells, exoskeletons and coral. Instead, tufa is formed by calcium precipitated out of water. Bits of the precipitated calcium carbonate can amalgamate to create larger rocks.

Ontario’s known tufa deposits are formed at springs and waterfalls, particularly along the Niagara Escarpment. Tufa is only known in Ontario from Brantford, Paris, Dundas, Niagara Falls, and with the discoveries reported herein, Silver Creek and Belfountain. In 2008, the Ontario Ministry of Natural Resources designated a tufa deposit in Brantford as a provincially significant Earth Science Area of Natural and Scientific Interest.

Tufa only forms at springs where just the right conditions exist. First, ground water must contain carbon dioxide picked up from the air, making the water weakly acidic. Second, the ground water must become supersaturated with soluble calcium by dissolving limestone. Third, as the calcium-rich water emerges from the ground, it must release enough carbon dioxide to cause the soluble calcium to solidify into insoluble calcium (rock). The same precipitation process is responsible for the formation of stalactites and stalagmites in caves.

Precipitated Calcium Carbonate in Tufa Pool at Silver Creek Conservation Area (Photo by Leanne Wallis)
Precipitated Calcium Carbonate in Tufa Pool at Silver Creek Conservation Area (Photo by Leanne Wallis)

Tufa was first found in the Credit River watershed by the author and assistant Pete Davis at Silver Creek Conservation Area. The author recognized it based on tufa deposits seen on a Hamilton Naturalist’s Club hike to Spencer’s Gorge (Dundas) led by Dr. Terry Carleton, a forestry professor at the University of Toronto. Dr. Carleton was the first to document tufa deposits at Spencer’s Gorge, which he recognized based on his observations of similar occurrences in England. News of the discovery at Silver Creek led to CVC’s Scott Sampson reporting possible tufa at Belfountain Conservation Area. A visit by the author, CVC’s Dawn Renfrew, biologist Lynda Ruegg, and Dr. Carleton confirmed the report.

Tufa deposits at Belfountain may be more abundant than anywhere else in Ontario. Tufa deposits can be easily observed at this conservation area on north-facing slopes. The best viewing spot is from the foot bridge that spans the West Credit River. The largest and most impressive tufa deposit can be seen from here on the slope on the south side of the river. This tufa deposit is almost completely covered by a blanket of moss in shades of green and red, with a small patch of whitish tufa peeking through.

Tufa deposits are a challenging growth environment for plants because soil is absent, the substrate is rock, conditions are calcareous, and there is a constant flow of cold water. Few plants can function in such environments; many of those that can are mosses, especially those specializing in seepy, calcareous habitat. Our tufa deposits, if not barren, tend to be either dominated by mosses, or populated by hardy plants such as Watercress (Nasturtium sp.), Jewelweed (Impatiens sp.) and European Coltsfoot (Tussilago farfara). The dominant moss on Silver Creek and Belfountain tufa deposits is Cratoneuron filicinum. It is not a rare moss, however, there are some provincially rare mosses known to grow on tufa that could be found in future inventories. Interestingly, because photosynthetic activity removes carbon dioxide from the spring water, mosses and other plants actually help create more rock once they become established.

In addition to potentially supporting rare mosses, tufa formation areas may also act as amphibian and dragonfly/damselfly breeding habitat. This is because tufa is often formed on slopes, creating terraces on which small pools of water are formed. Evidence suggests that salamanders (some of which are Species At Risk) may breed in these pools, and as some dragonfly/damselfly species restrict their breeding areas to seeps, they may also be found in these tufa pools. These spring-fed pools may also be an important water source for wildlife, especially if they remain unfrozen in winter months.

Tufa formation is a topic only recently receiving attention amongst biologists, and with increased awareness, the author expects more tufa deposits to be found in the future along the Niagara Escarpment.

Leanne Wallis
Credit Valley Conservation

Bobolinks and Forks of the Credit Provincial Park

In mid-July I watched a flock of bobolinks at Forks of the Credit Provincial Park. They were gathering prior to their incredible 10 000 km journey back to the pampas of Argentina.

Male Bobolink
Male Bobolink

The bobolinks of Forks of the Credit Provincial Park are good news for a species in sharp decline in Ontario and beyond.

Breeding Bird Survey data indicate an alarming 52% drop in Ontario’s bobolink population over the last fifteen years. In part this is because of their penchant for nesting in hayfields – hayfields that are often cut in June when bobolink young are still in their nests.

At the Forks bobolinks needn’t worry about whirring blades. But alas, even here, the future of bobolinks may be in jeopardy.

Forks of the Credit Provincial Park is gradually returning to its primeval state – forest. Ash, maple and choke cherry are reclaiming the meadowlands cleared by intrepid farmers long ago. Left alone, trees will prevail and the bobolinks will be gone.

Bobolinks though, are only one patch in the quilt of the glorious grassland ecosystem that exists at the Forks. Many other birds such as meadowlarks and a wealth of sparrow species including savannah, grasshopper and clay-colored will disappear as the trees return. And the extensive milkweed stands will vanish along with their famous patron, the monarch butterfly.

Forks of the Credit in Fall (photo by Fiona A. Reid)
Forks of the Credit in Fall (photo by Fiona A. Reid)

Park officials here (and I’m sure in other jurisdictions in Eastern North America) face difficult choices in the management of former agricultural lands in their care.

Should they honour the natural inclination of the land and allow trees to return along with the birds, animals and wildflowers that depend on them? Or should they intervene and kill the trees to save grassland and the myriad species it supports?

We need to start a conversation about the future of the grasslands at the Forks and elsewhere.

This story appeared originally in Notes from the Wild at inthehills.ca/blogs

by Don Scallen
Vice-President, Halton/North Peel Naturalist Club

Tough, tenacious turtles

Spring time is a time of new life and new beginnings: trilliums bloom, maple buds burst and red fox kits playfully tussle. At this time adult turtles are also thinking of new life, as they search out mates, breed and lay eggs. Turtles are fascinating creatures: there is fossil evidence that turtles have been around for 200 million years, which means they existed alongside dinosaurs. And turtles survived whatever catastrophic event(s) that led to the extinction of 90% of plant and animal species, including dinosaurs1.

Eastern Snapping Turtle, gravid female (with eggs). Photo by Joana Marques, CVC
Eastern Snapping Turtle, gravid female (with eggs). Photo by Joana Marques, CVC

Turtles are tough and tenacious. But the last two hundred years has seen the human population grow exponentially and impact their way of life. We all know some of the changes they’ve faced: wetland draining and filling, hunting, removal from the wild, roads built through wetlands and other habitat, road mortality, intentional persecution (particularly of Eastern Snapping Turtles).

The effect of turtle road mortality in particular is compounded by the inherent biology of turtles. Turtles have a high egg and hatchling mortality rate with very few making it to adulthood. Also, turtles take years to reach sexual maturity, in some cases 15 years or more. So when adult turtles are hit by vehicles, the impact on the population is much more severe than it would be on species which have greater reproductive success (e.g. raccoons). Tenacious turtles are still with us today, but population threats have led to 7 of the 8 native Ontario turtle species being considered species at risk of extinction or of disappearing from the province.

A critical time of the year for turtles is approaching: nesting time. Nesting occurs between late May and July and results in turtles moving around to find breeding partners and nesting habitat. In doing so, they may walk across roads, especially roads near wetlands. They also may use the sandy or gravely edges of roads to nest. While turtles may cross roads from April to October, their movement is at its peak in early summer.

Yes, turtles are tough, but they could use some helping hands. They haven’t evolved to handle humans in automobiles and earth-moving equipment… or maybe it’s more accurate to say that humans haven’t evolved to handle turtles. But some advances are happening right here in our watershed. In 2009, along a stretch of Highway 10 south of Orangeville where wetlands exist on both sides of the road, the Ministry of Transportation installed fencing to keep turtles off Highway 10 and direct them through a culvert under the road.

As early summer approaches, and you watch new life unfold, think of the prehistoric reptiles around you, these creatures of an ancient lineage, learning to cope in a new world with asphalt roads, fences, culverts, and two-tonne vehicles driving 100km/h through their home range. Imagine a turtle on a road shoulder about to cross, its eyes only 3 or so inches off the ground – such a limited field of vision – and knowing it will take some time to get across. I’ve seen a turtle stand on the road shoulder, faced as if it was about to cross, with cars whipping by, and looking like it was trying to find the right moment and work up the courage to cross2. The adult females of at least two of our turtle species risk their lives on dangerous roads due to something called nest-fidelity: the desire to return to where they were born to lay their eggs in the same place. So, many of the turtles you encounter on roads will be females carrying eggs or that have just nested. Like parents of other species, they are willing to put their lives on the line for their young.

So consider lending a hand to the turtles this nesting season. Drive slowly and scan the road, especially around wetlands, and if it is safe to do so, help turtles across roads. Be careful with Eastern Snapping Turtles which can bite (The Toronto Zoo and Kawartha Turtle Trauma Centre have youtube videos available on how to move a turtle across a road). If you encounter an injured turtle, contact the Toronto Wildlife Centre which admits injured turtles for rehabilitation. Consider sending observations of live or dead turtles to an organisation such as the Toronto Zoo’s Adopt-a-pond which runs the Ontario Turtle Tally.

Notes

1Some scientists still consider our birds to be descendants of dinosaurs, although recent research suggests otherwise.
2I was able to get this turtle across, but it took me a few minutes to find the right moment, and I had a much better view (and a bright jacket).

by Leanne Wallis
Credit Valley Conservation

Giant Swallowtails and Climate Change

Recently, one of the items covered by the news media was the change in distribution of various species owing to climate change. There are other causes for expansions of populations other than climate shifts but this discussion is limited to the global warming phenomenon. The media accounts included the recent appearance of fish species in the ocean much further north than where they normally occur. One species that was mentioned that has relevance to our own area was the Giant Swallowtail Butterfly.

Figure 1: Giant Swallowtail Butterfly adult, Prince Edward Point, May 30, 2009
Figure 1: Giant Swallowtail Butterfly adult, Prince Edward Point, May 30, 2009

While it is a good thing that the media covered this important story, they unfortunately got it wrong. To listen to what they were saying one was left with the impression the species involved were fleeing from excessive heat in their traditional areas and seeking respite in cooler areas. This is not the case. The geographic range expansion is possible only because the new areas are now offering conditions (slightly warmer) where the cooler conditions had prevented then from surviving before. Giant Swallowtails (Papilio cresphontes) are the largest butterfly in much of North America. Their wingspan ranges from 10 to 14 cm across! (Figure 1). They tend to stay in woodland areas or, in the southern US, in citrus groves. The adults sip flower nectar for food. The larvae of this butterfly are known as the ‘Orange Dog’, not for their colour but for their host in citrus groves. The caterpillars look a lot like bird droppings and can get as big as 4.5 cm long! (Figure 2)

They generally adopt a disguise by looking like bird droppings, an appearance that they retain until they pupate. Another deterrent to would-be predators is the osmeterium. This is a reddish, forked gland located behind the head that is extended when the caterpillar disturbed. The osmeterium exudes a fluid that is considered to smell terrible and deters any attacker.

Figure 2. Giant Swallowtail Butterfly larva on Common Hop-tree seedling, Windsor, September 6, 2011
Figure 2. Giant Swallowtail Butterfly larva on Common Hop-tree seedling, Windsor, September 6, 2011

In years past, Giant Swallowtails were essentially restricted to the far southern parts of the province. They would occasionally wander farther and one vagrant had been reported at Ottawa. Now they are much more frequent in parts of the province where they were seen only occasionally. How much of this recent range expansion is due to climate change is still unclear. Milder winters could certainly assist in the survival of the species over the coldest part of the year. A key limitation in their distribution is the availability of their host plants.

Hosts of the Giant Swallowtail all belong to the citrus plant family Rutaceae. We do not have many groves of oranges or lemons in Ontario to sustain the butterflies but we do have a few other members of the plant family. The list includes Gas Plant (Dictamnus albus), Cork Tree (Phellodendron amurense), Common Rue (Ruta graveolens), Common Hop-tree (Ptelea trifoliata) and American Prickly-ash (Zanthoxylum americanum). The first three mentioned are all introduced or non-native species. They are rarely grown and are thus hardly capable of sustaining populations of the butterflies in Ontario. The Hop-tree is rather uncommon in Ontario and restricted to the Carolinian zone. The main job of supporting the larvae of the Giant Swallowtails then falls to the Prickly-ash that has a much wider distribution than the others though it also tends to grow in more southern parts of the province. Prickly-ash is a relatively inconspicuous species that goes unnoticed unless one needs to cross through a patch of it. Then the thorns on its stems are more than adequate to grab the traveler’s attention. Other than vagrant butterflies that might be carried by the wind, the anticipated range of the butterflies is going to strongly mirror the distribution of Prickly-ash. Perhaps the changing climate will allow that plant to extend its range and thus allow the butterflies to follow further a field. It will be interesting to follow shifts in distribution patterns for these species as well as others that exhibit similar types of range restrictions.

by W.D. McIlveen
Halton/North Peel Naturalist Club