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author - Wallis, botany

Trilliums of our Watershed

Red Trillium (Photo: Leanne Wallis, CVC)
Red Trillium (Photo: Leanne Wallis, CVC)

It’s a lovely time of year to get outside for a romp through a nearby forest. By braving the mud and puddles, you can often be rewarded by some solitude from the regular summer and fall crowds, and wildflowers in spring are quite a sight.

One of the best-known flowers of spring is the White Trillium (Trillium grandiflora), our provincial flower. In fact, if you encounter any Trillium in our watershed, it is likely to be this one. Its large petals give it an alternate name of Large-flowered Trillium. Its petals are the longest of the four trilliums in our watershed. Its petals are indeed white, but can take on a pinkish hue with age. It is found in rich deciduous woods and often grows so abundantly as to appear to carpet the forest floor.

In addition to White Trillium, three other species are found in our watershed: Red Trillium, Painted Trillium and Nodding Trillium. Red Trillium (Trillium erectum) is the second-most common Trillium species in our watershed. It has brilliant crimson petals and is a thrill to encounter. It is reported to have a bad odour, giving it the alternate name of Stinking Benjamin. It is found in moist woods.

Painted Trillium and Nodding Trillium are quite rare in our watershed. In fact, I’m aware of only one location for Nodding Trillium, which is on private land a few kilometres from Caledon Lake. Painted Trillium is also quite rare in our watershed. It was known from only a historic record (1947) for our watershed until quite recently, but Natural Areas Inventory field work done since 2008 has found this species in three natural areas, one of which is Caledon Lake (NAI field work also made the Nodding Trillium observation). Nodding and Painted Trilliums are species of moist woods.

Trilliums are perennials that grow each spring from underground rhizomes. They are long-lived with White Trillium able to live at least 70 years. White Trillium flowers are primarily pollinated by bumble-bees and their seeds are dispersed by ants.

The Natural Areas Inventory (NAI) carries out vegetation community mapping, and performs flora and fauna inventories throughout the Credit River Watershed and Region of Peel. 2012 will be our 5th field season. If fellow naturalists are aware of any locations of Nodding or Painted Trillium in our coverage area, I’d be happy to hear about it.

Leanne Wallis
Credit Valley Conservation

author - Reid, mammals

Beavers – Natural Habitat Planners

Beaver (photo: Michael Patrikeev)
Beaver (photo: Michael Patrikeev)
http://www.wildnatureimages.org/

Every day I try to get in a walk to a natural habitat in my area. Sometimes it is just a stroll in my own backyard forest, but often I head over to Halton Regional Forest, or the St Helena Road
area. The big draws of these two sites for me are the ponds, and the ponds would not be there were it not for the industrious activities of our local beavers.

Beaver Lodge photo by Fiona Reid
(photo: Fiona Reid)

About four years ago, I was very disappointed to find one of my favorite beaver ponds off Sixth Line was empty. The grass was starting to fill in. I worried about the frogs, the dragonflies, and all the other animals that rely on that body of water. The two water snakes that shelter in the rocks and come out to sunbathe were nowhere to be seen. A passerby told me that Conservation Halton had removed the beavers and their dams in order to get more water into Hilton Falls, as the waterfall had dried up. They had placed very solid metal grilles projecting out in front of the flowing water so the beavers could not dam the stream at this narrow point where it passed under the track.

Beaver Dam photo by Fiona Reid
(photo: Fiona Reid)

Returning to the same area a few months later, I was happy to see that a pond had reformed. It took me a while to figure out what had happened, but when I crawled under the bridge, I saw what the beavers had done. Our industrious engineers had gone around the back of the culvert and stuffed it full of branches, positioning each branch parallel to the water flow, not perpendicular, as is their custom. The effect was the same, the water flow had almost ceased and the pond had refilled!

Pretty soon, the beavers added to their habitat restoration work by constructing a second dam upstream from the culvert, and order was restored. The branches in the culvert were swept away by storms, but the beaver pond lives on, the water snakes bask, the frogs croak and all is good!

by Fiona Reid
President, Halton/North Peel Naturalist Club

author - Wallis, reptiles

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

author - Reid, outings

Spring outing to Speyside area

Bluebird
Bluebird

We had a great outing that spring day. We started at my house in Speyside where we heard a Scarlet Tanager but did not see him, then saw a resident Indigo Bunting. We went to Town Line Road, seeing a Mallard on the pond, which is now very overgrown. Farther down we encountered a very large patch of Yellow Lady’s Slipper, a plant I have not seen in this area before. We also saw Rose-breasted Grosbeak.

Porcupine
Porcupine

We went over to the corner of Sixth Line and 15 Side Road where we had a wonderful time watching nesting Bluebirds, and we located 2 Porcupines and a Raccoon sleeping in three separate trees, and watched a Meadow Vole dash across the road. We also saw Eastern Kingbird, Indigo Bunting, Alder/Willow Flycatcher, Song Sparrow, Northern Flicker and Blue Jay.

We then went to Third Line south of 15 where we had fun watching a field full of Bobolinks, plus a few Eastern Meadowlarks, Red-winged Blackbirds, a Savannah Sparrow, and Barn Swallows. At the Scotch Block Reservoir we saw a lone Painted Turtle, many Northern Orioles, Northern Yellowthroat, Yellow Warbler, Cedar Waxwing, American Redstart and Warbling Vireo. The only water birds were Canada Geese, but a Great Blue Heron did fly overhead, as did a Red-tailed Hawk.

Thanks to Valerie Dobson, Jim and Joan Hughes, and their sharp-eyed guest Christine Rumble for coming along!

by Fiona Reid
President, Halton/North Peel Naturalist Club

author - McIlveen, insects/spiders

Pygmy Grasshoppers

Particularly in Spring, a walk in the woods might turn up a very tiny grasshopper among the dead leaves. These are likely Pygmy Grasshoppers, not ‘baby grasshoppers’. They are also known as ‘grouse locusts’ or ‘grouse grasshoppers’ or in one case, a ‘frog groundhopper’. Pygmy Grasshoppers are members of the suborder Tetrigodea and most occur in the Family Tetrigidae. One exception is Tettigidea lateralis that occurs in the closely-allied Family Batrachideidae. The seven species that are known to occur in our area are listed in the following table and samples are illustrated in the attached pages.

These grasshoppers, as their name implies, are quite tiny with adults ranging from about 7 mm to only 14 mm (half inch) in length. Females are slightly larger than males. Because of their small size and generally cryptic coloration, they are easily overlooked. They can be of various colours, browns though gray and mottled, but never green. Their eyes are rather pronounced and the pronotum is often elongated along the back to cover the thorax. The antennae are short and they lack auditory and stridulatory organs. Wings may be long or short.

Although they can tolerate slightly drier sites, most prefer to live on the ground in damp, muddy situations, frequently close to water. They are reported to feed on vegetation debris and microscopic algae that accounts for their preference for moist habitats. Eggs are laid in soil or mud. Because they over-winter as adults, they are likely to be active shortly after the snow melts in the spring. Given the mild winter this year that gives prospects for an early start to the season, we could expect to see these little fellows out and about in the very near future.

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

author - McIlveen, botany

Results of Monitoring Late-flowering Plants in Halton Hills, 2002-2011

The impact of climate on the biota of an area can be manifested in a number of ways. One possible effect of global warming and climate change in general is that the growing season could be extended. We can measure temperature changes easily enough but the effect of the temperature changes may not be immediately apparent. In part, this is because the changes will be gradual and small but changes are obscured by annual and daily variations. One means of assessing the long-term influence of climate changes is to follow the phenological changes in the flora. This could include such things as documenting the dates of first flowers (anthesis) or bud breaks of tree leaves. In the present investigation, we have chosen to record the dates when open or viable flowers are still present on plants in the area late into the season. This can be taken as one measure of a late growing season. It is not possible to know the exact date when an individual flower is no longer viable. In reality, the probability that the late-flowering blooms could be fertilized and go on to produce seed is rather low; however, the monitoring of such flowers over a period of time should provide a measure of the change in growing season dates.

Each autumn from 2002 until 2011, members of the Halton/North Peel Naturalist Club have conducted a survey of the plants still in flower in the latter part of November. The exact dates of the survey are indicated in Table 1. The dates ranged between November 14 and November 26. The exact locations of the survey have changed somewhat each year; however, the Willow Park Ecology Centre and the Lucy Maude Montgomery Garden in Norval have been checked every year. In the earlier years, the woods near the Georgetown Fair Grounds were examined while more recently the survey route included the Dominion Seed House Park. As well, incidental observations of flowering plants in parts of Georgetown have been added to the list.

Table 1. Survey dates and number of plant species in flower in Halton Hills, 2002-2011
Table 1. Survey dates and number of plant species in flower in Halton Hills, 2002-2011

Species observed still flowering on the survey dates are included in Table 2. The number of species in flower observed has fluctuated from year to year (Figure 1) but there is general trend to larger numbers over time. In part, the trend might have been influenced by the choice of sites visited; however, other factors such as site management at Willow Park and natural succession of species within an area likely played a mitigating role as well. Overall, the survey documented as few as 11 species still in bloom in 2003 and as high as 41 in 2009.

The vast majority of the 108 species on the list (Table 2) are cultivated garden species along with several species generally regarded as introduced weeds. The cultivated garden species includes several that are native species that have been purposely planted. Only about 10% of the species on the list are ones that are both native and endemic to the area. Only two species, Canada Goldenrod (Solidago canadensis) and Common Dandelion (Taraxacum officinale) were found flowering every year. Other commonly encountered species (6 to 8 years each) were Yellow Chamomile (Anthemis tinctoria), Calendula (Calendula officinalis), Garden Chrysanthemum (Chrysanthemum hybrid sp.), Wormseed Mustard (Erysimum chieranthoides), Scentless Chamomile (Matricaria perforata), Canker Rose (Rosa canina), Common Groundsel (Senecio vulgaris), Tall White Aster (Symphyotrichum lanceolatum), and New England Aster (Symphyotrichum novae- angliae). Interestingly, all of the species on the most common list except for the Wormseed Mustard and the rose are members of the composite family.

Figure 1. Number of plant species observed flowering in late November surveys in Halton Hills, 2002- 2011
Figure 1. Number of plant species observed flowering in late November surveys in Halton Hills, 2002- 2011

A survey of this type on its own cannot be expected to demonstrate that climate change is having a significant impact on the length of the growing season. In combination with many other surveys though, the data set will be more robust in demonstrating that a change is indeed occurring. This effort is a small contribution towards that end.

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

author - McIlveen, birding

Results of the 2011 Halton Hills Christmas Count

The 21st annual Christmas Bird Count for Halton Hills was held on December 27, 2011. The weather that day was marked by a fairly constant snowfall that restricted viewing of birds and generally made for a dull day with temperatures just above the freezing mark.

The results for the 2011 Count are summarized in the attached table. For comparison, the average and high numbers recorded for the previous 20 years are also included in the table. The total number of species recorded for the day plus Count Week was 56 and that is just below the maximum count of 57 species. The species count was bolstered by five new species including Northern Shoveller, Ring-necked Duck, Lesser Scaup, and Red- breasted Merganser observed at the Maple Lodge farms sewage lagoons. The Mute Swan was seen at an estate on the 10th Line near Terra Cotta but although it was counted here, caution needs to be exercised in case it is really a captive bird. With the new additions, the cumulative number of species for the Count Area rises to 101. Two species (Great Blue Heron and Easter Screech Owl) were found in Count Week and not on Count Day. The total number of birds (10777) is somewhat higher than the long-term average count of 9744. Considering the weather, the day has to be viewed as very successful.

New high numbers of Common Goldeneye (18) and American Robin (266) were encountered and this might be attributable to conditions prevailing during or slightly before the count period for 2011. New high numbers of Red-bellied Woodpecker (11) are likely due to increases in the local resident population for the species is known to be increasing substantially across Southern Ontario. Both Green-winged Teal and Bufflehead with two birds each increased from the previous high count of only one. Black-capped Chickadee matched the previous high of 465 birds. Other species were present in numbers within previously established ranges for the respective species.

In total, 23 people participated in the count, either as observers or as feeder watchers. Thanks to the following participants: Anna Baranova, Judy Biggar, Brad Bloemendal, Ray Blower, Mark Cranford, Betty Ann Goldstein, Charles Hildebrandt, Larry Martyn, Diane McCurdy, Irene McIlveen, W.D. McIlveen, Michael Pearson, Fiona Reid, Valerie Rosenfield, Don Scallen, Dan Shuurman, Chris Street, Rick Stroud, Janice Sukhiani, Jake Veerman, George Wilkes, Marg Wilkes, and Dave Williams.

Many thanks to Larry May for arranging access to the Maple Lodge Farms property and to Halton Regional Police for use of the community boardroom for the wrap-up session.

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

author - McIlveen, climate, insects/spiders

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