Sunday 1 July 2018

A few hours at Luther

Last Wednesday I had some early morning breeding bird surveys planned for a site near Southampton, while later that evening I was scheduled to complete some frog call surveys near Pickering. Finishing up early at my Southampton site I decided to spend a few hours in the middle of the day exploring Luther Marsh, located west of Orangeville and split between Wellington and Dufferin counties. Unfortunately heavy cloud cover and frequent rain was scheduled across most of southern Ontario for the entire day but I wasn't about to let that dampen my spirits!

Water Smartweed - Luther Marsh

My main goal was to find Butler's Gartersnake, a species that is apparently reasonably common around Luther Marsh but which I had never encountered in previous visits there. This Endangered species is only found in a handful of locales in Ontario. Having spent two summers radio-tracking and studying the species down in Windsor, it is one that I have a particular fondness for. It had always been a goal of mine to see some of the Luther individuals.

Long story short I wasn't able to turn up any Butler's Gartersnakes during my few hours there, but I blame that mostly on the weather. Heavy overcast with threatening rain is not the best conditions to be finding snakes out and about. Now if I could find some cover objects like tin or particle board, the search would likely have been much more fruitful.

Here's a photo of one of our study animals from the Windsor population, circa 2011.

Butler's Gartersnake - Essex County, Ontario (July 20, 2011)

One of the first non-avian species I noticed upon my arrival at Luther Marsh was a female Midland Painted Turtle, looking for a suitable location to dig a hole and lay her eggs. She was scratching around in the hard-packed mud and gravel at the edge of the parking lot, but when I returned an hour later she had vacated the spot. Evidently the ground here was not ideal. 

Midland Painted Turtle - Luther Marsh

Despite the dreary day there were lots of things to look at. All the typical breeding birds were singing, an American Bittern boomed off in the distance, a smattering of frog called emanated from the wetlands, and a variety of insects could easily be found in the grasses. Quite a few damselflies were present. My ID skills aren't up to par to identify bluets with confidence so I will leave these ones unidentified for now. 

Bluet sp. - Luther Marsh

Bluet sp. - Luther Marsh

Bluet sp. - Luther Marsh

A little easier to identify were these Sedge Sprites, their iridescent bodies glowing in the muted light. 

Sedge Sprite - Luther Marsh

Sedge Sprite - Luther Marsh

Walking through the long grasses and forbs would instigate a number of damselflies and moths to flit ahead of my footsteps. This one is a Watermilfoil Leafcutter Moth, which feeds on a number of aquatic plants including various pondweeds and water lilies. 

Watermilfoil Leafcutter Moth - Luther Marsh

A few Melanoplus grasshoppers were in the low grasses. They are difficult to identify at this stage!

Melanoplus sp. - Luther Marsh

Northern Leopard Frogs would occasionally shoot out of the grass just ahead of where I was going to step, which can occasionally be a little startling! 

Northern Leopard Frog - Luther Marsh

One of the main draws that Luther Marsh has to me is its large population of Mink Frogs. This is one of the furthest south locales for the species. Luther Marsh provides the perfect setting for Mink Frogs as the wetlands can have the appearance of bogs and marshes from much further north. 

Most of the wetlands that make up the complex around Luther Marsh have Mink Frogs but there are a few spots where I have found them to be exceedingly abundant. I went to my go-to Mink Frog Photography Location and had some fun photographing this variable species.

Mink Frog - Luther Marsh

Mink Frog - Luther Marsh

Mink Frogs are probably my favourite frog in Ontario for reasons I can't exactly pin down. Maybe it is because they are restricted to large wetlands in the boreal forest (generally), so they always seemed so far away when I was a herp-obsessed youth living in southern Ontario. However as I have gotten older and spent more and more time in the boreal it is apparent that Mink Frogs are quite common in large wetlands. Their chuckling calls are frequently heard at this time of year at most of my study sites in central Ontario. 

Mink Frog - Luther Marsh

Mink Frogs superficially resemble both Green Frog and American Bullfrog, two common species in most of Ontario. There are a handful of ways to tell them apart, however. The most obvious is the erratic patterning of dark spots and blotches on a lighter background that extends from the back down onto the lower limbs. Green Frogs and American Bullfrogs usually show dark striping that wraps around the legs; they rarely show erratic splotches on their legs. Another key ID feature is the prominence of the two dorsolateral folds, each fold beginning near the top of the tympanum and running down the back. Green Frogs have thick, obvious dorsolateral folds, while American Bullfrogs lack them entirely. Mink Frogs have less prominent dorsolateral folds, appearing intermediate between the two species. While there are other field marks to identify Mink Frogs, the above two are easy to see and very reliable. 

Mink Frog - Luther Marsh

This individual looked much different not that long ago, as it has only recently made the transition from tadpole to frog. The remains of its tail are still visible.

Mink Frog - Luther Marsh

While the sun did not come out during my visit, at least the rain passed to the north and south and I stayed dry. Just as I was getting ready to leave the marsh the sun almost came out, prompting a few butterflies to take to the wing. 

Common Ringlet - Luther Marsh

Northern Crescent - Luther Marsh

Silvery Blue - Luther Marsh

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