Landguard Bird Observatory have been ringing gull pulli (chicks) on Orford Ness since 1984, and to date have ringed over 11,000 birds – 9503 Lesser Black-backed Gulls (Larus fuscus) and 2102 Herring Gulls (Larus argentatus).

Up to and including 1995 the gulls were ringed using just conventional numbered metal rings, but since 1996 the Lesser Black-backed Gulls have also been fitted with a red plastic colour-ring. These rings bear a white three letter code (reading from the foot upwards) which can be easily read in the field with binoculars or a telescope, thus enabling the individual to be identified without having to be caught. Since 1998 the Herring Gulls have also been fitted with similar red colour-rings.

When birds are ringed using just a metal ring the vast majority of the recoveries are of birds, which are found dead. The great advantage of using coded colour-rings is that, as they are easily readable in the field, it is possible to get many sightings of one individual during its lifetime. It is therefore possible to track a bird’s movement and build up a detailed life history. It is also easier to accumulate and compare data on the productivity of each breeding season.

©National Trust

An indication of the effectiveness of using colour-rings can be seen when comparing the recovery rates. For the Lesser Black-backed Gulls, 5.7% of the birds ringed with just metal rings have subsequently been recovered/sighted. For the birds fitted with colour-rings this figure is 30.9%, over five times higher. The same comparison for Herring Gulls shows 8.9% against 59.8%, an improvement of almost seven times.

The Lesser Black-backed Gull a largely migratory species, most birds wintering in Iberia and north-west Africa. Over 600 of our colour-ringed birds from Orford Ness have been seen abroad, records coming from Germany (12), Netherlands (53), Belgium (34), France (107), Spain (129), Portugal (230), Italy (1), Morocco (93), Canary Islands (2), Western Sahara (4), Mauritania (4) and Gambia (1). The bird seen in Gambia is by far our most southerly recovery to date and involves a movement of 4611km.

By comparison our Herring Gulls are relatively sedentary, although some birds wander to the Low Countries and north France. To date we have had birds seen in France (28), Belgium (6) and Netherlands (19) but even these birds seldom move over 200km from Orford Ness. It was therefore a big surprise when, in April 1993, one of our Herring Gulls (ring KCY) was seen near Stavanger, Norway, a movement of about 800km. Just three weeks earlier this bird had been seen in Suffolk.

Anyone seeing one of our red-ringed gulls should report there sighting with details of the date, place and ring code to Mike Marsh: mike@imafxt.co.uk

All sightings will be acknowledged and a life history of the bird(s) involved will be given.

As with any species, but particularly migrants, factors such as movements, mortality, faithfulness to the colony where they were reared, all have to be understood if the species are to be effectively conserved.

As more is understood of the relationship between gulls and the flora and fauna on Orford Ness, the real value of the gulls in such a fragile ecosystem becomes better appreciated. Colour-ringing is an important tool in helping us to achieve this goal.