This sub-adult Least Tern is exhibiting a behavior known as food begging. Birds that are dependent on their parents for food during development learn to associate parents with feeding. Therefore, even as they become independent, young adults, if they see a parent they are likely to beg for food. Or they may fly over to the parent looking for an easy meal, as in this frame.
Birds, like most ducklings, that are independent at birth are known as precocial. Some precocial traits including being born with downy feathers and moving and feeding independently immediately after hatching. These birds do not associate parents with food and therefore do not exhibit food begging behavior. On the opposite end of the scale, birds that are altricial, like most songbirds and raptors, are born without feathers, are mostly immobile and fully depend on adults for food. Least Terns are considered semi-precocial. Although they are born with downy feathers and mobile at birth, they stay near the nest scrape and are initially fed by both parents. July 21, 2017