by Lynn Ovenden
A report on an OFNC excursion led by Gillian Mastromatteo on August 2, 2015
Petrie Island has quiet marshy interior bays, sandy beaches along the Ottawa River and lots of sunny openings in the forest in between. These make it a good place to find a variety of odonates. Gillian was hoping to find Slaty Skimmers, Blue Dashers, and Swamp Spreadwings, and we did – all within view of the parking lot.
We searched further west along the shores of the river, Crappie Bay, Turtle Pond, and Muskrat Bay and found several more species, including the Eastern Amberwing which is a Petrie Island specialty. It first showed up here in 2012 and is the only known spot in our region where they can be reliably found.
The most abundant damselflies were the Eastern Forktails, which come in three different colour forms (one for the males, one for immature females, and a third for the mature females). The most abundant dragonfly of the morning was the Autumn Meadowhawk (formerly known as the Yellow-legged Meadowhawk), which has yellow legs and is the last dragonfly on the wing in our area, often flying into mid-November. The ones we saw were all yellow or brown, either females and immature males, instead of the bright red of mature adults. Our only female Eastern Pondhawk took an interest in our group, landing right on one of the members!
Throughout the morning, Gillian explained the differences between damsels and dragons, their life cycle, and some feeding behaviours. For example, while some dragonflies perch and wait, others actively hunt for food on the wing.
We watched a Common Green Darner laying eggs by dipping its ovipositor in the emergent vegetation as it flew along from spot to spot just offshore. Gillian described the wheel-formation of pairs of mating damselflies and showed us how to see the tiny species-specific claspers at the end of the male’s abdomen of two different spreadwing species. You need a hand lens for that.
I especially enjoyed the skimmers along the marshy edge of Muskrat Bay: Twelve-spotted Skimmers patrolling back and forth, the shimmering orange wings of Eastern Amberwings either resting on pond lily leaves or chasing each other, and Widow Skimmers perched vertically in the coarse grass of the bank.
In addition, we saw three exceptional butterflies: a female Monarch (the first sighting of the year for many of the group) attempting to lay eggs on Swamp Milkweed, a Bronze Copper nectaring on Broadleaf Arrowhead flowers, and a Hackberry Emperor resting on a tree branch.
Overall, we found the following 17 types of odonates. See Gillian’s beautiful photos and notes on each species.
PETRIE ISLAND ODONATES, August 2nd 2015
Common Green Darner