Warbling Vireo breeds across the entire state of Michigan, and can be found from late spring to summer in the woods. About the size of a sparrow, this vireo lacks splashy field marks but you can still find them by listening for their loud, caroling song.
Males arrive in early spring from Mexico and northern Central America before the females. Much of their time is spent defending territories through song.
During courtship, a male approaches his prospective mate head-on, rhythmically weaving his body from side to side. With quivering wings, he closes the gap between them to about an inch, and if the female likes the male she will strike repeatedly at his open bill with her closed one.
Warbling vireos forage for insects in trees, hopping along branches and sometimes hovering. They also eat berries, especially before migration. Watch the video: https://youtu.be/i3PRxFpHnUw