Coloured Ringed Black Headed Gulls

Our breeding gulls return during March, so please consider adding a new dimension to your birding. As well as counting gulls, check for colour ringed birds – there is a good chance they will be here at this time of the year.

Since 2004 members of the Cotswold Water Park Ringing Group have been visiting breeding colonies to ring nestling Black headed gulls. Each bird is fitted with a metal BTO ring and a Darvic ring. The Darvic rings used in the CWP are white, engraved with a four digit code in black.  This code begins with 2 followed by two numbers and a letter. Each bird has an unique code so that it can be identified as an individual. It is possible to read this code in the field at moderate distance through a telescope.

Over 1000 gulls have been ringed in this way and we have received over 1000 sightings, many birds have been seen on multiple occasions.  From these sightings we know that black headed gulls hatched in the CWP migrate in winter to the south and west. Most are seen in SW Britain and Ireland but some go as far as Spain and Portugal.  We also know that most return to the CWP to breed.

A small but significant proportion of the CWP breeding population are colour ringed. A concerted effort by a few observers revealed over 50 colour ringed birds in the CWP in the 2012 breeding season.

Sightings of colour ringed birds are of great value to the project.  I would therefore like to ask anyone birdwatching in the CWP to make a special effort to read and report coloured ringed Black headed gulls.   At most sites used by the gulls rings can be read with a telescope, at some sites (e.g. Station rd car park) they can be read with binoculars. If you are a digiscoper or photographer it is often possible to read the code by enlarging the  image. Last year we read several rings on birds photographed in flight.

Please send sightings to me by email at  and I will send all observers a detailed history of the bird. At the end of the breeding season I will update all observers with a summary of sightings received.   John Wells

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