Sometime during the first week of May, witch-ity witch-ity witch-ity announces the arrival of the Common Yellowthroats at Fair Meadows. I scan the spring vegetation, then still low, and am always amazed at how difficult it is to spot such a loud bird. At last, I spy a beautiful male perched in a small mulberry tree and I can enjoy his sporty black mask and bright yellow throat. Nearby, a female is busy looking for food. Tired and hungry after their journey from northern South America, Central America, or the southern United States, the birds settle into the wet prairies and sedge meadows and feast on insects and spiders of all sizes and shapes.
Female Common Yellowthroat (photo by Gary Shackelford).
Common Yellowthroats are the most common nesting warblers at Fair Meadows. In late May or early June, when their singing is at its peak, you can walk most of the trails and never be out of range of their song. According to Cornell Lab of Ornithology’s Birds of the World, their song frequency prior to pairing has been clocked at an average of 125 songs per hour, with some recorded at 300 songs per hour! They sing more in the morning—no sleeping in late if you camp near a wet meadow in southern Wisconsin. The birds prefer shrubby, moist habitats and are considered wetland-dependent species. They nest in areas with bushy prairie plants such as baptisia, leadplant, and dogbane.
An adult male Common Yellowthroat feeds a juvenile an insect, possibly a cricket or katydid (photo by Gary Shackelford).
Common Yellowthroats are known to eat caterpillars, small dragonflies, moths, flies, beetles, small grasshoppers, and spiders. It is great fun to watch them move from plant to plant, inspecting each leaf (including a careful examination of the undersurface), and gleaning all those insects and spiders. Occasionally they will make a short sally after a moth or dragonfly that tries to escape.
How do scientists know what birds eat? In a January 2022 article in Ornithology by Brandon D. Hoenig et al, several techniques for studying bird diets are discussed. Early studies often relied on direct inspection of stomach contents, but required methods that are stressful or lethal and thus undesirable. Another classic technique is direct observation of foraging, feeding, or provisioning. Useful tools for this approach are a good camera and lots of patience. In recent years, digital photography and camera traps have further enhanced the ability to identify prey species. Newer techniques include DNA analysis of fecal samples or analysis of stable isotopes or biomolecules such as fatty acids in tissues or blood samples, which requires capture of the bird. Modern studies use various combinations of those approaches.
A juvenile yellowthroat, possibly eating a mosquito. There is another mosquito in the blossom over their head (photo by Gary Shackelford).
One day this summer after several days of rain, Gary observed several juvenile yellowthroats combing the common milkweed plants for food. Using the combination of patience and a camera, he captured evidence that led me to declare the Common Yellowthroat my hero—they were eating what appeared to be mosquitoes! Just another reason to celebrate this delightful, diminutive warbler.
Written by Penny Shackelford, Fair Meadows Sanctuary resident manager
Cover image by Gary Shackelford. A male Common Yellowthroat, with lemon yellow plumage and a black mask lined with white, perches in a berry-filled mulberry tree.
