Colour-ringingof adults and nestlings
This allowed us to follow individual birds, collecting detailed information on how long they live, where when and how well they breed, and if they disperse to other colonies to breed.
The photo on the right shows an adult with a metal numbered BTO ring, together with a red plastic ring. Below are pictures showing the rings which allow juvenile Tree Sparrows to be identified in the field. It has a metal ring and a unique combination of three coloured rings.