Where migrating birds go after summer breeding season ends. For example, Purple Martins migrate to the tropics of South America.

Curved upward or backward (as in a deformed bill.)

when behaviors are 'learned' or passed down in a culture.

Mistakes made by bluebird host, with good intentions but unexpected and disappointing (and sometimes embarrassing) results. Linda Violett may have used it first. See Downside.

Several females place eggs in one nest, and all adults care for the young. See Cooperative Breeding.

Returning to the same nest site in subsequent breeding seasons.

noise made by some species during egg laying. E.g., a female House Finch issues a loud, continuous egg cry during laying.

A fun term coined on the Bluebird Nut forum for a female bird that is expecting.

the harder outer body layer of an insect or arthropod. Grit helps birds pulverize this part.

how organisms figure out what direction to go in long-distance movements like migration - hypothesized.