Minnesota Outdoors: Common yellowthroats and songbirds are just now finishing nesting here

Blane Klemek

    There exists a species of warbler that belongs to a large group of what’s often referred to as “wood warblers”. Some 50 species of wood warblers occur in North America. The common yellowthroat is one of my favorites, although many others—some rare, some abundant—are equally as beloved, such as American redstart, ovenbird, golden-winged warbler, and yellow warbler.

    My little nickname for common yellowthroats is “raccoon warbler”. I sometimes call them “bandits”, and are so named for the striking and distinctive feature found on mature male yellowthroats—the black mask covering their eyes. As most all warblers, common yellowthroats are small birds and are only about four inches long.

    Common yellowthroats are also one of the most widespread and abundant species of warblers on the continent. Inhabiting a wide range of habitats in every state and province, with the exception of Alaska and Hawaii, common yellowthroats are at home in coniferous and deciduous forests, grassy areas adjacent to wetlands, within brushlands, and throughout prairie grasslands, too. Few so-called wood warblers are as adaptable as this little warbler is.

    Despite being abundant and considered a species of low conservation concern, it is reported that common yellowthroats have declined about one percent a year from 1966 to 2014, resulting, according to the North American Breeding Bird Survey, in a cumulative decline of about 38%. Global population is estimated at 87 million with around 54% of the population spending part of their year in the United States.

    Cornell Lab of Ornithology reports that common yellowthroats, despite the fact that they occupy such a wide variety of habitats, paradoxically might be suffering the most when it comes to habitat degradation, especially in relation to wetland loss, wetland degradation, and agriculture conversion. Moreover, Cornell concludes, “. . . because they are insectivores and often live in wetlands, they are also susceptible to poor water quality and to pesticides and other pollutants.”

    Still, any habitat improvement projects, whether those projects involve wetland and grassland restoration or forest stand enhancement projects, should benefit common yellowthroat populations, which I can attest. During my summers of conducting wetland vegetation and avian research in North Dakota for example, all of my study wetlands, which were all restored wetlands, had an abundance of common yellowthroats occupying the surrounding basins’ habitats.

    One of the most endearing traits of common yellowthroats is their natural curiosity whenever one is near them. During the breeding and nesting season, males vigorously sing from perches throughout their territory as they nervously and sometimes aggressively flit about defending and searching about. Many a time as I’ve listened to their telltale “witchity, witchity, witchity” songs in nearby habitats, I’ve employed the oft used “pishing” trick that all birders know and use. A few pishing sounds is usually all it takes to entice common yellowthroats into view, thus revealing their inquisitive nature and brilliant plumage coloration.

    As mentioned earlier, a distinctive, diagnostic characteristic of male common yellowthroats is the wide and dark black masks across their eyes. This highly visible feature on mature males signal to other males as potential rivals and, conversely, potential mates for females. In an experiment by researchers testing the significance of the masks, researchers placed paper black masks onto stuffed female common yellowthroats. The effect of the experiment was dramatic and showed that the mask initiated attacks by other males on the stuffed masked bird.

    Common yellowthroats are just now finishing nesting here in Minnesota. Sometimes raising two broods, the nesting season is winding down or completed for most songbirds as August all-too-quickly gives way to September and eventual autumn. Even so, that so many wood warblers call Minnesota home for a few brief months each year is nothing short of a blessing as we get out and enjoy the great outdoors.