During the night, the thunder was so loud it shook the house. In the morning, the Fair Meadows rain gauge had collected 2.8 inches of rain. The morning skies of September 21 were calm, though still producing a light sprinkle. The prairie and shrubs, however, were in motion. A quick survey with binoculars revealed the following species: Tennessee Warbler, White-throated Sparrow, Lincoln’s Sparrow, Common Yellowthroat, Nashville Warbler, Wilson’s Warbler, Black-throated Green Warbler, Eastern Phoebe, and Song Sparrow.
A localized patch of giant ragweed was bouncing as a family of Rose-breasted Grosbeaks (RBGB) hopped from branch to branch using their huge beaks to grasp and remove the seed centers of dried blossoms. Even in their fall plumage, we believe we were able to identify several family members. The adult male had a brownish back, a pale head stripe, and a rather pale pink breast, but still had his white and black wings. The female was brown with a streaked white breast and a prominent head stripe and supercilium (line above the eye)—the females’ plumage is similar year-round. The juvenile male also had the striped head and brownish color of the female but had a very buffy breast with a tinge of pink on the edge of the wing. In an article in The Auk published in October 1899, Witmer Stone noted, “The Rose-breasted Grosbeak exhibits about as great a variety of plumages as is to be found among our passerine birds.” The birds worked in the patch of ragweed for about 30 minutes, devouring each seed cluster before they moved on.
The preferred nesting habitats of RBGB are deciduous or mixed conifer forests, often with a shrubby component, throughout the upper Midwest and eastern United States in addition to central Canada. These birds tolerate human activity and may nest in parks, gardens, and residential areas. The little family we spotted may have nested in Canada or anywhere in Wisconsin, where the breeding bird surveys report nesting almost uniformly throughout the state. They are now on their way to Central America or northern South America, where they will winter in mid to high elevations in open forests or areas with scattered trees.
According to Birds of the World, RBGB consume a diet almost evenly divided between insects and seeds or fruits on their summer breeding grounds. During migration, they eat berries almost exclusively, but they will also eat the seeds of smartweed, pigweed, foxtail, milkweed, and sunflowers. The tired family stopping at Fair Meadows must have settled for the first food available.
Giant ragweed is a much-maligned native plant because many humans are allergic to its pollen, and its large size can create an ungainly appearance in gardens and along forest edges. However, giant ragweed also attracts pollinators and provides food for birds and many small mammals. It is relatively resistant to drought and has deep roots that help prevent erosion. I’m sure the hungry grosbeak family appreciated the food after a stormy night.
Written by Penny Shackelford, Fair Meadows Sanctuary resident manager
Cover image by Gary Shackelford. An adult male Rose-breasted Grosbeak in breeding plumage, showing black plumage on the head, back, and wings, which also have white spots. The bird’s underside is white with a triangular scarlet patch on the neck and chest, and he has a pale pink bill.
