The spring migration of birds through the midwestern U.S. brings a diverse richness to our local avifauna. Traveling in the northern reaches of Minnesota this past weekend, we met up with a few of those migrants on their summer breeding grounds.
We saw Chestnut-sided Warblers everywhere we went in northern Minnesota’s mixed deciduous-coniferous forests. Males were still highly territorial, singing continuously, even while foraging.
One of the most common and easily recognized of the warblers during the summer, Chestnut sided Warblers breed in extreme northeastern U.S. and southeastern Canadian mixed forest before migrating back to Central America for the winter. But they actually prefer second growth forest with shrubby understory where they forage, so their numbers have increased with logging of old growth forests.
Being able to ID birds by song is essential in the leafy forest; actually being able to hear well enough to find them where they are singing is even more essential. We manged to see and identify Yellow-rumped, Black and White, Mourning, Black-throated Green, Yellow, and Common Yellowthroat Warblers. Ovenbirds were ubiquitous in the forest as well.
The most commonly heard bird in the forest was undoubtedly the Red-eyed Vireo. Singing (loudly and continuously) from the tops of trees obscured by dense vegetation, we could hear them everywhere, but never saw one until we visited the headwaters of the Mississippi at Lake Itasca State Park.
A determined ornithologist once counted the number of songs sung by one individual Red-eyed Vireo male over the course of one day — an astounding 22,197 songs in 14 hours from dawn to dusk. The bird sang for 10 of those 14 hours.
Hardly bigger than a warbler, these vireos also consume a wide variety of insects all summer but increase the amount of fruit in their diet during the fall and in their winter habitat throughout South America.