On August 25th, I met the “migratory alter ego” of a Northern Waterthrush hopping along the narrow, sandy bank of the small island where the Confederation Park creek bifurcates. I was crouching on the opposite bank, in tall grasses and scratchy thistles, watching a Solitary Sandpiper wading in shallow water and probing the water’s surface to catch aquatic insects or other small invertebrates. Five other Solitary Sandpipers were also foraging nearby.
Like Solitary Sandpipers, Northern Waterthrushes eat mostly insects. They forage in shallower water than the longer-legged sandpipers or on the moist shore. The waterthrush sauntered along the shore for a minute or so, occasionally teeter-tottering its head down and tail up, and then disappeared into the island’s dense underbrush. A few times, the waterthrush reappeared to repeat this process. Once a Lincoln’s Sparrow showed up on the narrow sand strip. Without a telescoping lens, it was the same size and colour as the waterthrush, but it did not wander along the shore before returning to the underbrush. Like the Northern Waterthrush, Lincoln’s Sparrows mostly eat invertebrates caught by ground foraging and occasionally catch insects by flycatching (catching in flight). Unlike waterthrushes, Lincoln’s Sparrows can also eat seeds, which are their main winter food source.
Despite its name, the Northern Waterthrush does not belong to the Thrush family, like the American Robin. It is a Wood-Warbler, like the Yellow Warbler and American Redstart. On the Birds Calgary blog, a while back, I’d read that Confederation Park is a good place to see migrating warblers in Calgary from late August to mid-September. I did see a variety of warblers on August 24th and 25th. I had some trouble photographing them since they moved a lot in densely foliaged bushes. But it was fun to see some species I’d never seen before. I found the juveniles of some species quite hard to identify. In some warbler species, the juvenile plumage colours are similar to those of other species. Also, juvenile plumage can be quite different from adult male breeding plumage.
Easy to identify!
I initially thought this little one was a juvenile Bay-breasted Warbler. But after some research, I learned that Bay-breasted and Blackpoll Warbler juveniles have very similar plumage. The legs, however, tell them apart. Juvenile Blackpoll Warblers have yellow legs while juvenile Bay-breasted Warblers have grey legs (Powdermill Bird Banding Fall 2009).
This juvenile was easy to identify with its almost neon grey-greenish-yellow crown, nape and back, its two broad white wingbars and its white eye ring. However, it looks very different from the adults, who actually have chestnut coloured sides.
I also saw a few flycatchers and warbling vireos.
According to the introduction for Northern Waterthrushes in The Birds of North America Online, Northern Waterthrushes have distinct breeding ground and migrating personalities, hence the “migratory alter ego”. When I read about their breeding ground behaviour, I thought it would be a treat to observe that personality too.
The Northern Waterthrush is a bird of the northern forests, adding its loud, ringing song to the wooded swamps, bogs, and banks of North America’s great rivers and lake shores. Those familiar with this species on its breeding grounds know it for its spirited demeanor characterized by sharp chip calls, emphatic song, and energetic movements. It is also appreciated for its effervescent evening flight song, which compliments those of thrushes and the winnowing of snipes in the boreal forest evensong. However those who know the Northern Waterthrush well also know how seamlessly it switches to its alter ego—a furtive, skulking bird of thickets and shadowy understories. This is the personality familiar to many North American birdwatchers, who see it only on migration in back yards, city parks, and wet places, as it migrates to and from its wintering grounds in the tropical mangroves of Central and South America.
Whitaker, Darroch M. and Stephen W. Eaton. 2014. Northern Waterthrush (Parkesia noveboracensis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/182