How has begging changed as nestlings have grown?
Shortly after hatching nestlings began to give weak, high-pitched peeps. By week two begging calls had become two or three syllable, louder, harsher, and lower-pitched. As fledging nears in week three, begging nestlings give rapid, loud chattering notes, repeated often. As nestlings age their individual begging calls become more like those of their own nestmates, and less like those in other nests. It’s possible these call differences among broods will help parents identify their own young for feeding after they have left the nest.
