The Changing Composition of Migration

Carolina Wren

Most people are surprised when I tell them that “fall” migration generally lasts from July through December in Ottawa. First come the shorebirds, although the ones we see passing through in July are not leaving their Arctic breeding grounds because of a change in season, but because they were unable to find mates or because their nests failed, usually due to predation, severe weather, flooding, etc. Many of these non-breeders are first- or second-year birds that have completed the full journey to their breeding grounds only once or twice. Adult shorebirds which did manage to breed successfully follow next. They are quick to leave the north once their young have become fully independent; the young, migrating for the first time, follow at a more leisurely pace. Because different species leave at different times, and because birds migrating south do so at a slower pace, it is possible to find migrant shorebirds from July through November, when the cold-tolerant Purple Sandpipers – generally the last of the shorebirds to head south – move through Ontario.

The Dunlin is one of the later shorebirds to show up in Ottawa.
Andrew Haydon Park, November 2008.

In mid-August, the first migrant songbirds begin moving through. The less cold-tolerant, insect-eating warblers, flycatchers, grosbeaks, vireos, wrens and swallows begin migrating in August and are usually gone by the end of the September, while other insectivores, including kinglets, pipits, and thrushes, can be found in late September through early October. Sparrows, blackbirds, finches, and other songbirds who feed on seeds and berries may also be found in October. Of course, there are exceptions within each group. While the Yellow Warblers are the first to disappear at the beginning of September, Yellow-rumped Warblers can still be found in Ottawa in mid-October. Similarly, the Alder and Willow Flycatchers leave their breeding grounds early, while the Eastern Phoebe – the first flycatcher to arrive each spring in April – is the last to leave in late October.

Last come the waterfowl, whose migration lasts from late September or October until the local rivers and lakes freeze up. Some species, such as the Blue-winged Teal, leave their breeding grounds even earlier, in mid-August, and travel all the way to South America. Other species, such as the Common Goldeneye, travel only as far as they can find open water, spending the winter on the Great Lakes and open rivers such as the Ottawa and Rideau Rivers in the Nation’s Capital.

The Willow Flycatcher is one of the first flycatchers to leave.
Moodie Drive Marsh, June 2011

During the last weekend of September I witnessed the changing composition of migration for myself. Saturday started off cool and foggy, so I went out a little later than normal. The sun was starting to shine when I arrived at Sarsaparilla Trail, though it was still cool enough to wear gloves. All of the hawks and falcons had moved on, but the resident Belted Kingfisher, Great Blue Herons, Swamp Sparrows and Red-winged Blackbirds had been joined by a few Golden-crowned Kinglets, Yellow-rumped Warblers and a male Wood Duck in breeding plumage. All of these birds, with the possible exception of the kinglets, will be gone by the time the snow flies.

The Green-winged Teal often sticks around through November and early December.
Andrew Haydon Park, November 2009

The diversity of species was much more impressive along the river at Shirley’s Bay and Andrew Haydon Park. New waterfowl species have arrived; I spotted a large raft of scaup, two Red-necked Grebes, a Red-breasted Merganser, and a single male Common Goldeneye – all firsts of the season for me – on the river at Shirley’s Bay, while a group of Redheads had joined the Green-winged Teals in the bay west of the dyke. The usual Great Egrets and a handful of shorebirds were feeding on the mudflats, including Lesser Yellowlegs, Least Sandpipers, Semipalmated Sandpipers, Pectoral Sandpipers, and a single Wilson’s Snipe. I was hoping to see a Dunlin or two, but struck out on that account. In the songbird department, Yellow-rumped Warblers were flitting among the trees on the dyke, Dark-eyed Juncos were foraging on the ground, and a flock of about 20 Pine Siskins flew by, another first of the season for me. In the woods I heard a Gray Catbird “mewing” and saw a Brown Creeper, a couple of Purple Finches (one of which was singing), and more Golden-crowned Kinglets.

I decided to head to Andrew Haydon Park after that. Another egret was present in the water near the western mudflats, and a couple of Blue-winged Teals were feeding in the shallow water. One was sleeping on a log next to a female mallard with its beautiful green and blue wing patch showing, so I crept up to them in order to take a photo. It’s not often that I see these teals and a Common Goldeneye in the same day, but anything is possible in September!

Blue-winged Teal and Mallard

Later that evening I stopped by the Moodie Drive quarry and found my first Snow Goose of the fall and a small, dark-mantled gull on the sandbank which might have been a Lesser Black-backed Gull. It was sleeping with its head tucked into its feathers. Ruddy Ducks and two Pied-billed Grebes were still present on the quarry pond, along with a huge number of Canada Geese which all flew off when a gunshot somewhere south of the pond startled them.

The following morning was gray and drizzly. At Sarsaparilla Trail I encountered my first White-crowned Sparrows of the fall, two juveniles feeding on the ground with a White-throated Sparrow; with the Song Sparrows, Swamp Sparrows, and juncos, I tallied five species of sparrow altogether. The White-crowned Sparrow is one of the later sparrows to pass through Ottawa, along with the handsome Fox Sparrow; I typically don’t look for these species until October. Other good birds at Sarsaparilla included a single Great Egret stalking fish on the pond, five Hooded Mergansers, a Yellow-bellied Sapsucker, and an Eastern Phoebe hanging out behind the outhouse.

As the light, misty rain showed no signs of letting up, I drove over to Mud Lake with the intention of walking through the woods. First I stopped by the Ridge, where moderate numbers of Yellow-rumped Warblers and White-throated Sparrows were foraging in the rain. I also encountered a Hermit Thrush skulking in the dense thickets at the western end of the ridge and a Carolina Wren scolding me from beyond the fence. This appears to be a different individual than the one that has spent the past year behind the houses further south along the western fence line. While checking the trails west of the lake I heard a Carolina Wren singing loudly from the thick foliage of someone’s backyard. I had never heard him singing before and wasn’t sure if someone was playing a recording, so I played the Carolina Wren’s song on my iPhone to see what would happen. Sure enough, this little brown dynamo flew out and engaged my iPhone in a duet.

Carolina Wren

In the woods I also found a pocket of songbirds moving along the trail; there were at least three Ruby-crowned Kinglets, several Yellow-rumped Warblers, a Northern Parula and a Palm Warbler in the flock. I heard three or four more thrushes “chipping” in the thickets of sumac field, though I only spotted one, another Hermit Thrush. I also noticed a bright yellow Ambush Bug lurking among the blue blossoms of a Veronica flower. It was nice to see this colourful predator, as the insect diversity at this time of year is much diminished. For example, I only saw one dragonfly this past weekend, a large mosaic darner hunting above the pond at the base of the waterfall at Andrew Haydon Park, and no butterflies.

Ambush Bug

On the lake, I counted one female Hooded Merganser, at least 20 American Wigeon, 10 Ring-necked Ducks, and 30 Woods Ducks. Mallards, American Black Ducks, and Canada Geese were also present. A female Common Merganser in the channel between the Ridge and the rapids brought my number of merganser species for the day up to three and my total number of waterfowl species for the weekend up to 17. So many waterfowl species present in the Ottawa area and the arrival of White-crowned Sparrows can only mean one thing: that fall migration is starting to wind down.


3 thoughts on “The Changing Composition of Migration

  1. Some beautiful photos, thanks for sharing. I like the lighting on that Willow Flycatcher, and the colors on the ambush bug photo. It was fortunate to be able to catch both wing patches on the Blue-Winged Teal. I’ve been watching them at Andrew Haydon for the last few weeks, but they’ve always been too busy dabbling in muddy water to make themselves photogenic.

    I do wish the Blue-Winged Teal would stick around longer than they do. It always seems like they disappear (from AHP, anyway) before the males finish coming out of eclipse.

  2. Thanks Suzanne! I was lucky to catch this one dozing with her wing patches visible. All the other teals were bulldozing through the water with their heads down. Yes, I wish they would linger in Ottawa than they do. I only see the males in breeding plumage in the spring, and they aren’t as accommodating.

  3. Pingback: Highlights from 2012 | The Pathless Wood

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