Imagine this Black-capped Chickadee flying toward its nest, carrying fresh insects for its chicks. A moment later, it emerges with a tiny white pouch in its bill. The chickadee drops the object into the vegetation below. That outgoing payload is a fecal sac, a remarkable adaptation found in nesting songbirds. Nestlings — often within seconds of being fed by an adult — excrete waste in tidy little sacs. Then the dutiful parent switches tasks, from meal delivery to waste management.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.