Recovery
With several recoveries at various times and places, the migratory route, location of stopover places, winter sites, and average flying speed can be charted for a given species.
Mist-net
First, the birds need to be caught. A simple and common method is to use a delicate mist-net like the one on display. When a bird flies into the net, it is trapped in a flexible "pocket" without being injured.
Reporting form
The location, date, species, ring number, age and sex are carefully recorded on a standard form. The bird's size, weight and amount of stored fat on its belly are often noted, as well. The completed form is sent to the Museum of Natural History to be kept on file.
Flying fuel
The amount of fat a bird stores up indicates how much food it has eaten and how far it can fly before eating again.
