Northern
Parula

The female builds a hidden, hanging pouch-like nest by tunneling into the center of the moss and hollowing out an egg cavity.

They feed heavily on small spiders and canopy insects, often glean-hunting while hanging completely upside-down from outer tree branches.

There is an odd geographical gap in their eastern North American breeding range across parts of the Midwest and Northeast, which scientists suspect is tied to air pollution affecting the growth of their required nesting lichens.