Mesurer le bec d’un oiseau

The linear measurements of birds include differents elements: wing length, tail length, tarsometatarsus length, but also bill length, bill depth and bill width. These data are used for example to distinguish subspecies and populations, but also to study growth patterns, the effects of the migrations, the difefrences between sexes, …
The vernier caliper is the main device used to measure the bill of a bird. In this article, we presnet you the notions of bill length, bill depth and bill width, and how to use a dial vernier caliper.