For the Birds Radio Program: Swainson's Thrush
What were all those little brown birds running about in the Northland two weeks ago? 3:07
Every fall migration has its surprises, and the biggest surprise this season has been the amazing number of Swainson’s Thrushes everywhere in Duluth. For over a week, these robin-shaped brown birds were found by the dozens in backyards, and by the thousands at Park Point, eating mountain ash berries and skulking in shrubbery. When I’d drive to the Lakewood Pumping Station in the predawn gloom, I’d see hundreds of thrushes in my headlights flying up from the side of the road.
Swainson ‘ s Thrush used to be called the Olive-backed Thrush, and many observers noticed just that feature when they were in their yards . It has a white underside with dark spots on the breast, and a robin-like expression on its huffy face. This is a common breeding bird in the spruce fir forest–I usually hear a few on my breeding bird survey route. Its song reminds me of a backward Veery’s , spiraling up instead of down.
Swainson’s Thrushes eat a lot of fruit as well as insects, and in turn provide sweet treats for migrating hawks. In 1908, ornithologists at Point Pelee, Ontario, wrote that they “suffer greatly during the Sharp-shinned Hawk flights… During the periods of this hawk’s abundance, little scattered piles of thrush feathers can be found every here and there through the underbrush.”
Here in the Northland, sharp-shins naturally time their migration to coincide with songbird flights, and since Swainson’s Thrushes weigh three or four times as much as warblers, they are obviously a serious target for hawks. But hawks are hardly the only ones who eat them. In my neighborhood, little piles of thrush feathers are more likely to come from house cat than hawk attacks.
In 1923, a Dr. Charles Townsend heard distress calls of a pair of Swainson’s thrushes, and when he checked it out, he “found two of these birds flying about a Red Squirrel who sat erect on a fallen tree, holding in his fore-paws a partly eaten thrush in the spotted juvenal plumage. The squirrel’s face was smeared with blood and it was altogether a most lamentable spectacle.”
If predators aren’t bad enough, there are also ticks and lice to contend with, and internal parasites like tapeworms to boot. When people hear these ethereal singers, we tend to think of angels flying through the heavens with carefree abandon. Thrushes face far more danger and unpleasantness than we do, but they live their short lives with beauty and song, feeding our souls with their loveliness and making this a truly magical autumn.