Tree Swallows glisten in the June sunlight, as they swoop and glide, their arcs interlacing in the air. When a white feather flutters down among them, one swallow snatches the feather in its bill and flies upward, as another gives chase. After a moment, the lead bird lets loose the feather, which drifts lazily, until the second bird swoops to catch it in midair. Loose feathers are important for Tree Swallows. They line their nests thickly with them.More info and transcript at BirdNote.org. Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.