Bruce Pit: Tiger Beetles and a Rare Dragonfly

Striped Hairstreak

Bruce Pit is under-valued as a great spot to see a variety of insects at the peak of summer. Though I’ve spent a lot of time looking for dragonflies there, it wasn’t until recently that I realized it could be good for other types of insects as well. In 2020 I found a species of tiger beetle there that I had never seen before, Punctured Tiger Beetle, and last year I observed it again, as well as another type of tiger beetle: the colourful Festive Tiger Beetle. Tiger beetles have long flight seasons, but are not active during the entire summer; they become inactive or aestivate (the summer equivalent of “hibernate”) during the hottest part of the year, so it is easier to find them towards the beginning and end of summer. I started visiting on June 17th this year, hoping to find some good odes, butterflies, and a few different tiger beetles for my life list.

I found a couple of interesting bugs that day, including two different tiger beetles: the first was the ubiquitous Six-spotted Tiger Beetle, while the second was a Festive Tiger Beetle! I hadn’t expected it to be so easy to find the Festive Tiger Beetle, but it was scurrying along the same sandy path where I’d had one last fall.

Tiger Beetles have a distinct way of moving: they quickly run and stop along the ground like a Killdeer or robin, and if you walk too close to them they will fly ahead of you and land a few feet away before scuttling along again looking for prey. I usually notice them when I scare them into flight and see them land close by; most other bugs that are flushed usually fly off and disappear altogether. Fortunately they can be approached by moving very slowly and carefully toward them, sometimes close enough for a macro photo.

Festive Tiger Beetle

Festive Tiger Beetles look dull and brown on cloudy days, but are a colourful purple-green when the sunlight hits them just right. They have a few simple cream-coloured markings along the edge of the wings as well. I only saw the one, but it was thrilling how easy it was to find! A few brilliant green Six-spotted Tiger Beetles were flying as well, and I got a macro photo of one too. These are the most commonly seen tiger beetle in our area, perhaps because they are bright green and lack the brown camouflage of the other tiger beetles in our region.

Six-spotted Tiger Beetle

A Fragile Forktail along the creek was also good to see. Although they are not as abundant or widespread as the Eastern Forktail, I have had good luck finding them this year.

Fragile Forktail

My best find, however, was one that I didn’t manage to get a photo of: a Black Saddlebags flying over the field at the top of the toboggan hill. I had clear looks of this southern dragonfly through my binoculars as it was low enough to see the shape of the “saddlebags” at the base of each hindwing. It disappeared over the trees toward Cedarview Road, so I walked down to the pond where I saw another flying over the water near the marshy area. At that point I continued my walk around the pond, running into a fellow birder who told me that she had seen a Black Saddlebags flying above a grassy field near the creek. She doubted what she had seen – she recognized the species from Point Pelee but didn’t think we had them here. Although I didn’t see any in that area, I found another Black Saddlebags out over the water much further out and another one over the parking lot. There appeared to be at least four or five around, and I did not find any perching. I had seen this species here once many years ago but not last year, so seeing more than one was quite amazing!

I returned on June 20th for a quick check of the pond after an appointment and brought my net this time, wading into the water at the northwestern corner in the hopes of catching a Black Saddlebags to photograph. I had no luck, though it appeared there were at least two individuals still flying.

On June 22nd I returned with my net, and spent some more time in the same corner of the pond trying to catch one over the water. Again I had no luck, but on my walk around the pond I finally found one patrolling the grassy area near the bridge, too high up to catch. A little further along I found one patrolling the path along the north side and finally it perched in a bare tree about 15 feet up!

Black Saddlebags

I was able to walk right beneath it and get a photograph to put it into iNaturalist. There were probably still three or four individuals around, though I never saw more than two at one time. I looked for but didn’t see any signs of breeding (pairs in tandem or in wheel formation, or any females ovipositing). They have been here nearly a week now, and while it seems most likely that this small population emerged here it remains a mystery as to when they arrived and whether they will successfully colonize the area.

Black Saddlebags

It was thrilling to see so many and get some photographs after not seeing any since my last trip to Presqu’ile Provincial Park!

I had another Festive Tiger Beetle in a sandy spot at the eastern end of the pond, but that discovery paled in comparison to finally being able to photograph the Black Saddlebags. The light hit it just right at some angles so that it appeared as green as a Six-spotted Tiger Beetle, though I wasn’t able to catch this colour on camera.

Festive Tiger Beetle

On my most recent visit on July 7th I didn’t see any Black Saddlebags or Festive Tiger Beetles. My first stop was the base of the toboggan hill to look for the colony of Acadian Hairstreaks I’ve seen there regularly for the last six or seven years. To my disappointment the tall grass had been mowed all the way from the top of the hill to the marsh at the bottom – right to the water, destroying the verge of wildflowers where the Acadian Hairstreaks used to nectar. I checked the remaining wildflowers at the side in case any were feeding on the sparse milkweeds and cow vetch, but couldn’t find a single one. The caterpillar of this species depends on willows for food, so hopefully they are still present and the adults have dispersed elsewhere. It was a big disappointment to see the lack of flowers here as this is has been the most reliable spot for seeing Acadian Hairstreaks in my area for several years now.

Bottom of the Toboggan Hill

From there I headed to the field at the back to look for Gray Treefrogs, butterflies and dragonflies, and came across a Northern Cloudywing sitting in the middle of the path leading to the eastern field. This was interesting to me because I had scared one up from the same location on two of my previous visits; clearly it was very territorial about that spot.

Northern Cloudywing

A little further along the path I found some tiger beetles scurrying along and was happy to see at least three Punctured Tiger Beetles. These ones are quite drab compared to the Festive Tiger Beetle, with hardly any pale markings on the carapace (the hard outer wings covering the back) other than a line of small dots on each side. It is named for those pale spots which are actually small pits or “punctures”.

Punctured Tiger Beetle

This species lives in sandy open areas, such as trails and along sidewalks; in fact, it has also been known as the Sidewalk Tiger Beetle. Interestingly, it may be entirely green in the southwest part of its range (it lives as far away as Arizona), with the small punctures reduced or absent!

Punctured Tiger Beetle

Ontario is home to fourteen species of tiger beetle, 11 of which can be found in Ottawa according to observations uploaded to iNaturalist. Now that I’ve seen a few I’ll definitely be paying attention to see what others may be around!

The best insect of that outing was not a dragonfly or tiger beetle, however, but a Striped Hairstreak perching out in the open! These used to be the most difficult hairstreaks for me to see, as they don’t seem to have any reliable territories around me – unlike the Banded Hairstreaks at the Rideau Trail, Banded and Hickory Hairstreaks at South March Highlands, and Acadian Hairstreaks at Bruce Pit. Now that honour goes to Coral Hairstreak, which also doesn’t seem to have any reliable territories in my area. However, I have seen both Coral and Acadian Hairstreaks at Marlborough Forest (as well as Striped), so that may be my best option for finding them.

Striped Hairstreak

It’s been a lot of fun seeing so many neat critters at Bruce Pit. I’ll be keeping an eye out for more Black Saddlebags here in the future, as it would be wonderful if they started breeding in the Ottawa region. Who knows what other unusual or uncommon insect will show up next!

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Citation

Ontario Tiger Beetle field guide created by Mark Conboy in his blog post Ontario Tiger Beetles on Ten Million Earthlings. Post dated October 17, 2016 and accessed September 16, 2022.