A Visit to Roger’s Pond – Part I

The first day of the Victoria Day long weekend was warm and sunny and gorgeous; it felt more like a day in mid-summer than late spring. I took my insect net out for the first time this season and headed over to the Cedar Grove Nature Trail in Marlborough Forest to see what I could find. Although I knew many of the butterflies and dragonflies unique to Marlborough Forest would not have emerged yet, I still had hopes of finding some interesting reptiles and amphibians. I was also curious as to whether I would find any interesting birds there, as I had never been there before during migration.

When I arrived I was happy to see a couple of emeralds circling the parking lot. Because of the unusually cool and wet spring we’d had, it has been a slow start to the dragonfly season; it was encouraging to see a couple flying around as soon as I got out of the car. I found even more odonates when I climbed up the short trail to the rocky ridge above the parking lot…there were dozens of freshly emerged damselflies sitting in the vegetation, and I had to be careful not to step on any. While on the ridge I heard a Black-throated Green and Chestnut-sided Warbler singing, and found my first Harvester of the year.

Harvester

I encountered more dragonflies as I followed the main trail toward Roger’s Pond, each patrolling its own 15- or 20-foot section of the trail. Most of them seemed to be emeralds, and all of them were too busy to stop and perch someplace so I could confirm their identity.

After leaving the woods and entering the open area dominated by cedars, I noticed that the ditch next to the trail was filled with water. This was an indication of just how much rain we’d received in recent weeks; numerous Green Frogs and one Leopard Frog were taking advantage of all the puddles and sitting in the water right beside the trail.

Green Frog

Even the clearing used as an illegal dumping ground was below water, with multitudes of tadpoles swimming near the edges. This was a disappointment as I was hoping to turn over some of the boards that litter the area in search of snakes and salamanders.

It wasn’t possible to enter the clearing without getting my feet wet, so by the time I finished my exploration my shoes and socks were soaked. I did see (and hear) a Black-and-white Warbler in the trees where the small side trail enters into the clearing; I also heard the distinctive “chick-bang” of a Scarlet Tanager calling somewhere in the woods.

Junkyard under water

From the “dump” I proceeded directly to Roger’s Pond, where I found tons of dragonflies and damselflies. I saw Chalk-fronted Corporals, immature whitefaces, a Common Green Darner, American Emeralds and Beaverpond Baskettails. The damselflies here had progressed beyond the vulnerable teneral stage, so I netted one and took a few photos of the tip of its abdomen for identification. C. Lewis identified it as a Boreal Bluet, one of our early spring damsels. It is a gorgeous sky blue colour.

Boreal Bluet

I came across a couple of colourful Six-spotted Tiger Beetles as well. These beetles can generally be seen from April to August in open woods, and along paths and streams. They are easily identified by their bright metallic green body, legs and antennae. Each outer wing, called an elytra, has three to five white spots.

Six-spotted Tiger Beetles are diurnal predators. Their diet consists of small insects, spiders, other beetles, springtails, sawflies, caterpillars, flies, ants, and grasshoppers. Even the larvae, which live in tunnels in the soil, feed on ants, spiders, and other small prey it can grab. At night, the adult beetles return to the same burrow in which they spent their larval stage. Adults also spend the winter in their burrows.

Six-spotted Tiger Beetle

There were a few birds at the pond, including three adult Canada Geese shepherding ten goslings. Red-winged Blackbirds, Common Grackles, and a vocal Pied-billed Grebe were also present. I walked across the metal bridge (the water below was running very fast) and startled a Northern Water Snake sleeping in the grass. I didn’t see it until it uncurled itself and shot off through the grass, down the steep bank and into the water where it vanished.

Further along the trail, I was quite startled by an upside-down insect peering out from the shadows beneath a leaf not too high off the ground. I thought it was alive at first, perhaps a large spider of some kind. Being curious, I dropped my insect net over the leaf and waited for the creature to make a move. It didn’t. That’s when I suspected it was an inanimate object, and picked it up. It turns out it is a dragonfly exuvia (plural: exuviae), the skin left behind when it transforms from aquatic larva to adult dragonfly. I picked it up and placed it on a leaf to get a few pictures.

Dragonfly exuvia

Dragonflies begin their lives as eggs laid in or around water. These eggs hatch into larvae called “nymphs” or “naiads”; they are fully aquatic, and can not only swim like fish, but also breathe through gills. Dragonflies may spend anywhere from a few months to a few years in the larval stage, depending on the species. Once they mature, they crawl out of the water, attach themselves to a rock or vegetation, then burst out of the larval “shell”, leaving the case behind. In some ways this is like the snakeskin left behind when a snake sheds.

This was the first dragonfly exuvia I’ve found, and it was fun to examine it. I sent a photo to Chris Lewis, who thinks it is the larval case of an emerald; certainly there are lots of them around Roger’s Pond. Identifying exuviae is difficult, however, and takes a lot of patience and effort.

I left the larval case on the leaf and walked toward the edge of the water. There I came upon this Mink Frog sitting on a mat of vegetation:

Mink Frog

The Mink Frog was one of the “specialties” of Roger’s Pond that I was hoping to see; I was not disappointed! Although I’ve heard these frogs described as “very timid”, this individual was completely unfazed by my approach and just sat motionlessly in the water. As a result, I got some terrific shots of this accommodating species.

So far my visit was off to a great start; and although I found many more interesting things during the rest of my exploration, I took so many photos that I’ll have to post those in Part II!

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