The total value of an artist’s artworks sold at auction over a specific period. This metric reflects the artist’s overall market activity and demand in monetary terms. The middle value of all realized ...

Radar tracking allows you to follow along to see what birds are flying overhead as the birds move to their summer feeding grounds. "The movements are massive," said Andrew Farnsworth, a migration ...

These lessons were designed to accompany the first two parts of the PBS ... or landing, birds must overcome the tremendous energy demands of flying. Methods for meeting those energy demands ...