Tree Swallows (Tachycineta bicolor) are blue-green above and white below with blackish flight feathers and a thin black eye mask; females are duller with more brown in their upperparts, and juveniles are completely brown above. Juveniles and some females can show a weak, blurry gray-brown breast band. Tree Swallows are a familiar sight in summer fields and wetlands across northern North America. They chase after flying insects with acrobatic twists and turns. Tree Swallows breed in open habitats such as fields and wetlands, usually adjacent to water. They nest in artificial nest boxes as well as tree cavities. Foraging flocks are frequently seen over wetlands, water, and agricultural fields. Migrating and wintering Tree Swallows can form enormous flocks numbering in the hundreds of thousands. They gather about an hour before sunset and form a dense cloud above a roost site (such as a cattail marsh or grove of small trees), swirling around like a living tornado. With each pass, more birds drop down until they are all settled on the roost.
The cache is placed along a seasonal road that is unplowed during the winter. I saw several Tree Swallows flying over the marsh just to the south. I wanted to use a nest box for the cache, but didn't have time to make one. You will need to bring your own pen to sign the log, and you may want to have boots.