Cliff swallows are the miniature masons of the bird world! One mud pellet at a time, a thousand times over, pairs build their rounded brick-and-mortar nests in colonies on cliffs or human-made structures like bridges or building eaves. Though similar in many ways to their relatives, barn swallows and tree swallows, the pronounced glow of their bright forehead in the doorway of each nest gives them away. In flight, their squared-off tail and buff-colored rump help set them apart. The lively pace