IN 1899, Hans Christian Mortensen, a Danish schoolteacher, made little rings from a sheet of aluminium and fitted them to the legs of starlings; bird-ringing had been invented.
Soon, ringing schemes were up and running in Germany, Hungary, Britain and Scandinavia. The technique, known as ‘banding’ in America, has been invaluable to bird study but, with millions of rings fitted in over a century, you might expect that little more can be learnt using it. The environment, however, is in constant flux and so are the lives of birds. Ringing remains an indispensable tool.
Responding to global warming, some species are moving closer to the poles. Black-tailed godwits, for example, used to return to their Icelandic breeding grounds in May. Now they arrive in April. Does earlier nesting affect a bird’s breeding success? Are migrants adapting successfully to new, more northerly, environments? How important is temperature at nesting sites?
The report on ringing and nest recording in Britain and Ireland during 2014, which has appeared, examines some of these issues. A “constant effort” ringing method, known as CES, is yielding particularly valuable results.
Of seven migratory species studied, only one, the reed warbler, bred more successfully at higher latitudes although, the authors say, “there was evidence of local adaptation in six species”. Breeding success, however, is not all down to conditions where birds nest. Studies of flycatchers and warblers revealed that “carry-over effects of passage regions impacted on the timing of breeding more strongly than climate on the breeding grounds”. Redstarts, for example, bred earlier in years with higher rainfall in the Sahel.
Over 1m birds were ringed during 2014 and 28,187 rings were recovered, yielding some interesting records. A roseate tern, ringed as a nestling at Rockabill, Co Dublin, travelled to Iceland. It’s only the second record of the species there. Roseates go south for the winter; that one flew 1,301km northwards is odd.
A bar-tailed godwit, ringed at Dublin Bay in January 2014, was in the extreme northeast of Norway four months later. Only four bar-tails ringed in Ireland or Britain have been recorded there. Rings usually come to light when a bird is found dead but this one was alive and well; its ring number was read in the field.
Others were not so lucky. A snipe from Belarus was shot in Monaghan, 2,324km from home. The body of a little tern was found on a ship off Sierra Leone, 4,998km from Kilcoole, where the tern had been ringed as a nestling. A redwing from the Cote d’Opale, France, was killed by a car in Ballyhale, Co Kilkenny.
Another casualty is especially interesting. A chaffinch, ringed in Lithuania, was killed by a cat, 1,940km away in Gurteen, Co Galway. Chaffinches from mainland Europe visit us in winter but this is the first Lithuanian one known to have travelled to Ireland or Britain.
Dunnocks were regarded as dull unadventurous birds until a famous Cambridge study showed what scandalous lives they lead. It was thought also that they didn’t travel much. However, one ringed on the Isle of May in September 2013 was trapped by a ringer in Norway the following March. It was caught again, six months later, 129km away by another Norwegian ringer.
New longevity records have been set. A black-headed gull, ringed in Worcester and found dead in the Netherlands, was at least 32 years and four months old.
A guillemot, ringed as a chick on Canna in the Inner Hebrides in 1978, was 35 years 11 months and 29 days old when re-trapped back there in 2014. Little things tend to have very short lives but a long-tailed tit, weighing the same as a €2 coin, had reached the ripe old age of eight years and 11 months when re-trapped in Wiltshire.
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