By mid-August most dragonfly species are on the wane. A few families are still quite abundant, particularly the darners and meadowhawks, while small numbers of other skimmers and a few clubtails often linger into September. Forktails, bluets, and some spreadwings are also still common in the appropriate habitats in August and September. This makes it worth going out to good dragonfly habitats such as large rivers, lakes and marshes to see a decent variety of species.
Large dragonflies this time of year are particularly interesting; while Common Green Darners are the most frequently encountered large dragonflies of late summer, you might come across a Black-shouldered Spinyleg basking on the rocks along the river, a Wandering Glider zipping over a meadow, a Twelve-spotted Skimmer flying above a pond, or a group of mosaic darners swarming through the air late in the afternoon. The mosaic darners are a particular favourite of mine; they are large brownish-black dragonflies with mottled spots of blue, green or yellow depending on the sex. While they spend most of their time flying through the air hunting for small insects, I often come across them perching vertically on thick stalks of vegetation below knee-height in open grassy areas early in the morning. We have several different species in Ottawa, and trying to find something other than the ubiquitous Canada and Lance-tipped Darners is a fun exercise.
Although birders tend to refer to “spring” and “fall” migration, many birds begin heading south in mid- to late August, and a few (such as shorebirds which are unsuccessful in finding a mate) even begin migrating in July. In Ottawa, this southbound migration often overlaps with post-breeding dispersal, which means that even in July and August it is worth checking familiar places for birds that may be moving through. This year, southbound migration began for me on August 19th with a trip to the Rideau Trail off of Old Richmond Road. I usually start checking the boardwalk and hydro cut for migrants this time of year as the edge habitat and buckthorn bushes loaded with berries can be fantastic for warblers, flycatchers, thrushes and other migrants. Most of the birds I saw or heard were likely local residents, although the Black-and-white Warbler I heard singing here may have come from deep within the woods or elsewhere, and it was pretty neat to see an Ovenbird strolling along the boardwalk. A squeaky Rose-breasted Grosbeak and two Least Flycatchers calling made me think these birds were moving through, as this section of the trail is normally pretty quiet in the summer.