Dragon-hunting: Petrie Island Specialties

Blue Dasher

If you are a dragon-hunter in Ottawa, summer isn’t the same without a stop at Petrie Island in July. It is a great spot to see a number of species that are difficult to find elsewhere, so I try to get out there a couple of times each season. On July 6th Chris Lewis, Mike Tate and I visited Petrie Island together. The weather was not the greatest – the sun danced in and out of the clouds all morning, and it grew very hot and humid as the morning wore on. By the end of our two-and-a-half hours there, we were hot, sticky and uncomfortable and I only wanted to go home to my air-conditioned house. The intermittent overcast conditions meant that we didn’t see as many species as we would have liked, but we did manage to see several Petrie Island “specialties”. The birding was good, too, though we didn’t see anything really exciting. An Osprey was the best bird of the outing, though the usual House Wrens, Tree Swallows, Common Yellowthroats, American Redstarts, Eastern Kingbirds, and Great Crested Flycatchers were present.

As usual, we started scanning for damselflies in the vegetation along the shore as soon as we left the parking lot. We found two of our target species right away: Orange Bluet and Vesper Bluet. I spotted a teneral Orange Bluet first, which is a transparent bluish-violet colour instead of orange. Shortly after that I found an adult in all of its black-and-orange glory. The abdomen looks unusually long in this image, perhaps because its wings are fanned out:

Orange Bluet

Orange Bluet

Orange Bluets are more difficult to observe than other damselfly species because they spend much of the daylight hours away from the edges of the lakes, ponds and streams in which they breed. They tend to return to the water in the late afternoon until dark, which is when mating usually occurs. They may also be found close to the water on cloudy days. Orange Bluets prefer ponds that are covered in water lilies, which is typical of the sheltered bays of Petrie Island. This one has several mites on the underside of its thorax:

Orange Bluet

Orange Bluet

The Vesper Bluet is another Petrie Island specialty that is neither blue nor spends much time near the water – at least in the early part of the day. Like the Orange Bluet, the Vesper Bluet prefers ponds and lakes with lily-pads but spends most of the day in the trees and vegetation away from the water. The males return to the water in the late afternoon, where they watch for females from low perches. They pair up and mate until after dark, later than most other damselflies, which is the reason they are called Vesper Bluets – vesper is an archaic English word meaning “evening”.

Vesper Bluet

Vesper Bluet

Forktails were also abundant in the vegetation. I only managed to spot one Fragile Forktail, but wasn’t able to get a decent close-up of it. His black and green colouration helps him to blend in well with the rest of the foliage. This is what I typically see when examining the vegetation at Petrie Island for damselflies (click to enlarge):

Petrie Greenery

Petrie Greenery

The Eastern Forktails were much more accommodating. Mature females are purple with green eyes, while males are green and black with a blue-tipped abdomen and green eyes.

Eastern Forktail (female)

Eastern Forktail (female)

Eastern Forktail (male)

Eastern Forktail (male)

Mike pointed out a pair of dueling hairstreaks further along the Bill Holland Trail. One landed on a leaf just above my head where I was able to photograph it and identify it as a Banded Hairstreak. We didn’t see any Hackberry Emperors, a rare butterfly in Ottawa and another Petrie Island specialty. Its larval foodplant, the Hackberry tree, grows along the Beaver loop of the Bill Holland Trail.

Banded Hairstreak

Banded Hairstreak

We also missed the rare Unicorn Clubtail on our outing; it’s been two years since my last sighting in July 2012.

Although Swamp Spreadwings were common, it seemed as though the normally abundant dragonflies such as Eastern Pondhawk, Blue Dasher, and Slaty Skimmer were hard to find in their usual places along the Bill Holland Trail, so we turned around and checked the Muskrat Trail. We had better luck there, observing a couple of male Slaty Skimmers and Blue Dashers resting in the vegetation near the water. The Slaty Skimmer is one of my favourite dragonflies with its beautiful dark blue body and matching pterostigmas, the two coloured rectangular cells along the leading edge of their wings.

Slaty Skimmer

Slaty Skimmer

I also found a male Blue Dasher to photograph, obelisking to reduce the amount of sunlight hitting his body. I was happy to see that there were still a few around, although the Blue Dasher population in Ottawa does not seem as high as it was a few years ago when they first exploded onto the local scene.

Blue Dasher

Blue Dasher

Once again it was a treat to go dragon-hunting with Mike and Chris on Petrie Island. I loved seeing the gorgeous Orange and Vesper Bluets, still relatively new to me, as well as old favourites such as the Blue Dasher, Slaty Skimmer and Eastern Pondhawks.

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