[Chirping] [An American robin sits in its nest.] [A Robin’s nest is a familiar sight…] [..but, have you ever seen a Cliff Swallow nest?] [Two cliff swallows call while sitting in a mud nest. One flies away.] [Cliff Swallows use their bills to gather mud alongside puddles, streams, or lakes.] [Several cliff swallows on the edge of a stream gather mud.] [A cliff swallow in a nest deposits a mud pellet onto the nest. Another swallow flies in with mud in its beak and they trade spots, with the first one flying away. It adds its mud pellet to the nest.] [The finished nest contains about 1000 individual mud pellets.] [Another swallow carefully deposits a mud pellet onto its nest.] [A cliff swallow perches on the edge of its nest.] [All in a day’s work for the “bricklaying” Cliff Swallow.] [The swallow scratches its head with its foot, preens, and calls.] [Explore more at AllAboutBirds.org]

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Cliff Swallows build their mud nests on cliff faces and other vertical surfaces in colonies containing hundreds, even thousands of other birds. They also build nests in the eaves of buildings. The pair works together, gathering pellets of wet mud in their beaks and laying them down one by one in rows until the structure almost reaches the overhang above. Swallows deposit mud pellets onto the nest with a shaking motion leaving behind well-formed nuggets that bond with the others and harden into a strong nest wall. Technically called an adherent cup, a finished nest contains over 1,000 mud pellets. Cliff Swallows tuck their nests away in corners and make sure that the nest opening is small so the eggs and nestlings are well protected from predators like hawks, owls, snakes, and mammals.