Once migration winds down, many birders stop visiting Mud Lake while they look for breeding birds elsewhere. Although birds such as Wood Duck, American Redstart, Yellow Warbler and Common Ravens are abundant and easy to find at the city’s premier migration hotspot during the breeding season, many of Ottawa’s summer specialties – such as Grasshopper Sparrow, Lincoln’s Sparrow, Golden-winged Warbler, Mourning Warbler, and Sedge Wren – are found elsewhere, and so most birders switch their focus from looking for migrating transients to chasing these summer residents down just as soon as the last Blackpoll Warblers and Arctic Terns disappear in early June. This is about the same time my attention to dragonflies and butterflies intensifies – and Mud Lake is a great place to find a good variety of both these insects.
There are more species of dragonflies at Mud Lake in the summer than there are butterflies, but there are enough interesting butterfly species here to make any visit worthwhile for people interested in both insect families. While I don’t think anyone has compiled a list of butterflies found at the Britannia Conservation Area, in 2003 Bob Bracken and Christine Lewis published a list of odonates that they observed here over the course of eight years; their total came to 50 species. An update in 2004 brought that total up to 51 species with three additional species found along the shoreline close by. Those articles can be found online in Ontario Odonata Volume 5 and Volume 6, published by the Toronto Entomologists’ Association. A few of the common species seen on my walk today are as follows:
This is a very common and abundant species in the Ottawa region, most often associated with ponds and small lakes with a substrate rich in organic matter. While I often see great numbers of these black and white skimmers at places like the South March Highlands, Stony Swamp, and Roger’s Pond, this was the first time I’d really noticed them at Mud Lake. I found a few along both the north and south sides of the pond. Look for the white markings on top of the thorax (just behind the head) and along the first few segments of the abdomen to differentiate them from other black and white skimmers.
This early season dragonfly is found in much the same habitat as its larger relative, the Chalk-fronted Corporal. They are typically seen perching on vegetation floating in the water; I was lucky to find one perching on a leaf on the shore. These small dragonflies are entirely black except for the white face and a small yellowish-white dot near the end of its abdomen. There are usually lots along the shoreline at Mud Lake, and they are common elsewhere as well. This was one of the first dragonflies I learned to identify on my own after asking Google what dragonfly has a white face and a dot on its tail…if only they were all so easy!
Back in 2003 Bracken and Lewis described this species as “rare” at Mud Lake, recording individuals in only two of the eight years (2002 and 2003) that they conducted their informal study. Each record consists of a single male caught and released at the northeast corner of the pond. While they theorized that this species breeds here, more and more observations over time would seem to prove them correct. I have found them several times in the years since I started my own adventures in dragon-hunting, and today I found at least four individuals: the one shown above on a rock along the northeastern shore of the pond, and three more chasing each other at the southwestern corner of the pond! This one landed briefly on a downed tree trunk close to the water before dashing off in pursuit of an interloper in its space.
All of the individuals I found were males. The males in the southwestern corner of the pond were quite territorial, landing in preferred spots on vegetation over-hanging the water before being chased off by another male. I had fun watching and photographing them, though I did wonder where all the females were.
This handsome big river dragon didn’t even make the list in either 2003 or the 2004 update. Chris Lewis and I used to go all the way out to the Quyon Ferry landing or Morris Island to look for this species; since those early years (around 2016) this species has been found at Sheila McKee Park, at Andrew Haydon Park, and now at Mud Lake. Is it expanding its range? Becoming more abundant in its range? Or are there more people actively looking for dragonflies – and being able to identify them?
This one landed on a tree leaf above my head as I was walking along the shoreline of the small bay east of the filtration plant looking for its smaller relative, the Lancet Clubtail (which I didn’t find on this visit). It was just out of reach of my net, so I spent some time photographing it. The black cross-stripes of the face are noticeable in the photo below; this is one of the key differences that separates the Cobra Clubtail from the similar-looking Midland Clubtail, which was found emerging on the break-walls of Britannia Bay west of the conservation area in 2004.
This is another common skimmer at Mud Lake. While males are easily recognized in their mature form, due to their white abdomen and alternating black and white patches on each wing, females and tenerals are easily confused with female Common Whitetails, which have brown bodies and brown patches on the wings (twelve patches in females and four in teneral males). The easiest way to separate these two species is by checking the yellow markings on the sides of the abdomen – Common Whitetails have a series of yellowish-white triangles, while Twelve-spotted Skimmers have a single yellow line running down the length of each side.
Interestingly, while both cruiser species found in the Ottawa area have been observed at Mud Lake in recent years, only the Stream Cruiser made it onto the list back in 2003 and 2004. Bracken and Lewis describe this species as “rare” at Mud Lake, having observed one individual in May 1998 and another one on June 29, 2003. They suspected at the time that this species breeds in the Ottawa River, and given that Mud Lake is one of the most reliable places close by for me to find it, I think they are right. Despite their name I almost always see them patrolling sun-dappled trails in the woods near water, and this year I found one individual patrolling the woods in the southeastern section of the conservation area. Fortunately it perched, and I was able to get some photos.
I saw what was likely a second individual in the southwestern corner patrolling the path there, but it flew off into the trees before I could be certain.
Also noteworthy were a teneral Eastern Pondhawk and a teneral Widow Skimmer both in the storm water pond at the extreme southeastern part of the conservation area. A Common Green Darner patrolling the lake was my only darner of the day, and I did not see any emeralds.
I had two good butterflies at Mud Lake today, both along the same section of the shoreline where I found the Cobra Clubtail. The first was a Canadian Tiger Swallowtail trying to obtain nutrients from the damp soil at my feet while I was trying to find a good spot to photograph the clubtail! I quite like these large butterflies, and was disappointed it wouldn’t come out into the open for a better photo.
The second was a Long Dash Skipper. Very few skippers are found at Mud Lake; however it is interesting that this is the second year in a row I have seen this species here. Last year I found one in the western sumac field near the Rowatt Street entrance on June 29, 2019. This one was on the complete opposite side of the conservation area, right next to the river. It was feeding on the Yellow Irises that grow there.
Indeed, I think this is one of the rare times I’ve seen this species on perching a flower, so I spent a lot of time taking its picture!
I had a great afternoon at Mud Lake, with the unexpected Cobra Clubtail my best find of my visit. The Stream Cruiser was also great to see, proving once again that Mud Lake is a great place to visit in any season if you enjoy watching all types of wildlife.