In Carver County, the Swainson’s thrush (Catharus ustulatus) is mostly seen as a spring and autumn migrant. If you get a sense of movement on the ground, or with a quick glance out of the corner of your eye, you might think you’re seeing a Robin. But with a few more seconds to look at it, the lighter brown back and tail, buffy tan markings around the eyes and face, and a pale chest with spots indicate you’ve encountered a Swainson’s thrush.
In May and September, it passes through the county — to and from its nesting areas in northern Minnesota and in Canada. Its scientific name refers to the purity of its flute-like song and its brown color.
(A BRIEF DIGRESSION: The bird’s English name comes from William Swainson, a 19th century English ornithologist, who also is remembered with the Swainson’s Hawk and Swainson’s Warbler, along with six South American birds. Swainson was also a malacologist — a person who studies mollusks (snails, slugs, octopus, squids, clams and mussels) and a naturalist illustrator. His online biographies offer insight into scientific work in the 1800’s.)
The Swainson’s thrush height (7”) and wingspan (12”) are smaller than the much darker “robin red-breast,” but it has cousins that can also be seen here and cause some identification confusion: gray-cheeked thrush, veery, hermit thrush and wood thrush.
Males and females look the same, and they don’t seem to travel in pairs. They feed on ground insects, worms and caterpillars. In the fall, they will also be eating berries and fruits from bushes.
In the spring, you might hear males singing to attract a mate. Singing stops after nesting, so they won’t be advertising their southward trip to Central and South America in September.
Bird-banding has shown that some individuals have lived for 10 years, and the species might migrate along the same path each year. That could be good news for birders who can plan to repeat their observations with optimism.
However, it can also be bad news if a building is put in its way. Minnesota reports more Swainson’s thrushes are killed by collisions than any other migrant. This happens during cold-front passage, low cloud cover and reduced visibility during rain and fog.
Hopefully, Carver County folks are lined up with safe passageways for Swainson’s thrushes, and we are able to hear them sing and enjoy finding them in our yards or on the many trails through our communities.
For more information:
The Sibley Guide to Birds, David Allen Sibley
Birds of Minnesota, Robert B. Janssen
Breeding Birds of Minnesota, Pfannmuller, Niemi and Green
The Audubon Society’s Encyclopedia of North American Birds, John K. Terres
Birds of the World, Cornell Lab of Ornithology
Online: All About Birds, Cornell Lab of Ornithology LINK
Online: Minnesota Breeding Bird Atlas
