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.

Observation of breeding adults

By watching adult tree sparrows as they build nests and collect food for their chicks, we gained insight into how they use the habitat near to their nests, and what types of habitat are important sources of food, and which they avoid.

Hundreds of hours were spent reading colour rings on birds coming in to these feeders

Monitoring of nesting attempts

This allowed us to determine how well different areas and habitats support breeding tree sparrows – how many nesting attempts do they make (tree sparrows can make as many as four attempts in a summer), what are their chances of succeeding, how many chicks do they fledge from an individual attempt, and how well those chicks survive.

Tree sparrow nest with chicks
© Rob Field

Examination of chick diet 

Microscopical examination of the undigested remains of insects in the faecal sacs produced by chicks has allowed us to describe the diet of tree sparrow chicks at Rutland Water and other colonies, giving further insight into how they use their habitat. The vast majority of this work was done by Derek Gruar at RSPB.