Birds are monitored by putting a ring on their leg. The ring can then be used to identify the bird if it’s captured or seen with a telescope/binoculars/camera by someone else, or if their carcass is found. Typically it’s just a small metal ring but these days multiple colored rings can also be used, those are put into a public database that anyone can use to identify the bird and see where it has been spotted, when it was ringed, how old it is etc.
Birds are monitored by putting a ring on their leg. The ring can then be used to identify the bird if it’s captured or seen with a telescope/binoculars/camera by someone else, or if their carcass is found. Typically it’s just a small metal ring but these days multiple colored rings can also be used, those are put into a public database that anyone can use to identify the bird and see where it has been spotted, when it was ringed, how old it is etc.