BTO: Are you sure that’s ‘your’ blackbird?

Blackbird. Picture: www.grayimages.co.uk / BTO

Blackbird. Picture: www.grayimages.co.uk / BTO

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On a low branch, overhanging a water-filled ditch just around the corner from work, there is ablackbird nest containing five youngsters, their wing feathers just beginning to emerge.

On a low branch, overhanging a water-filled ditch just around the corner from work, there is ablackbird nest containing five youngsters, their wing feathers just beginning to emerge.

This isthe second brood of chicks to have been raised in the nest this season, the first having fledged successfully back in April. This is one of the 1,500 or so blackbird nests being monitored through the BTO’s Nest Record Scheme this year, a sample of the 13 million nesting attempts that will be made nationwide by this familiar species.

Perhaps because it is so familiar, the blackbird remains a firm favourite with garden birdwatchers.

Many such observers can be heard in conversation referring to ‘their’ blackbirds but, given that one blackbird looks very much like another (at least within the sexes), how do you know that the bird using your lawn over successive weeks is really the same individual? Blackbirds are territorial during the breeding season but they will share ‘communal’ feeding areas where food is plentiful and it may well be that your garden is being used by a number of individuals from neighbouring breeding pairs.

Some insight into the numbers using a typical suburban garden comes from another BTO study, a project that involves the use of coloured rings to allow the identification of individual birds. The project, which is known as RAS (Retrapping Adults for Survival), is used to collect information on how the survival rates of birds change over time and acts as an early warning system for possible problems within the wider environment. The project covers a wide range of bird species, with some of the volunteer bird ringers concentrating their efforts on blackbirds. Over the course of just a few years Dave Leech, one such ringer, has caught and colour-ringed 457 different blackbirds in a small Norfolk garden. While some of these birds are just passing through, others have been resighted locally by householders over the following weeks and months –http://holtblackbirdproject.wordpress.com. This sort of project underlines the contribution that householders and birdwatchers can make, their sightings of colour-ringed birds providing valuable information.

Many different researchers use colour-ringing as a core part of their projects and there is plenty of opportunity for you to contribute to our understanding through the resighting of ringed birds. If you happen to be on the Suffolk coast watching the gulls, scanning a flock of wintering geese or simply watching the birds in your own garden, look out for individuals carrying colour rings. Make a detailed note of what you have seen and, importantly, the colours of the rings and their position on the legs (most birds carry a combination of ring colours). More information can be found on the BTO website – www.bto.org/ringing ), which also has links to pages where you can report your sightings.