© Mindaugas UrbonasMute swan.

What was probably the world's oldest mute swan has been found dead in Denmark. This unusual example of Denmark's national bird lived to just past the ripe old age of 40. The previous record for a mute swan was 28 years old.

The swan was found dead at Korsør Skovstrand on Christmas Day last year. It was ringed and its leg ring was sent to the Copenhagen Bird Ringing Centre at the Zoological Museum at The University of Copenhagen. The number on the ring was Helgoland 112851 and after checking their records, the centre realised that this was no ordinary dead swan. It turned out that the swan had been ringed on 21st February 1970 at Heikendorf near Kiel in northern Germany and that it was at least a year and a half old when it was ringed.

"This swan has lived an unusually long time, and the chance of finding another swan of the same age is practically zero" believes Pelle Andersen-Harild, Denmark's leading swan expert.

He has ringed birds for the Copenhagen Bird Ringing Centre for many years. Oddly enough Pelle Andersen-Harild was also the person who caught and checked the now deceased record holder in February 1979 - also at Korsør. At that time it weighed 11.1 kg.

"Thousands of swans died in the winter of 1979, so that shows that this was a large well-nourished bird in very good health" said Pelle Andersen-Harild to the Danish news bureau Ritzau about the find of the record breaking bird.

The oldest swan recorded prior to this bird being found was a young bird that was ringed at Karrebæksminde in Denmark in 1970 and found dead in eastern Sweden in 1996. Scientists estimated it to be at least 28 years and 7 months old, which, although old for a swan, is nowhere near the swan that has just been found.

Ringing birds

Ringing birds is a Danish invention. It was a head-teacher from Viborg, Hans Christian C. Mortensen, who came up with the idea of ringing birds in 1899 and since then it has been a global scientific success.

Here in Denmark swans began to be ringed in 1928 after the breeding population had been almost eradicated in the years prior to this. Up until 1962 only 455 swans had been ringed. Today approx. 43,000 mute swans have been ringed - most of them in the 1970s. An especially large number of birds - 5000, were ringed during the so-called "Big Swan Raid" in 1970.

"Now the oldest bird in the Danish swan population is dead. However it has to be considered a successful and lucky bird since it survived 5 extreme winters in its lifetime, including that of 1979 where it was weighed by Pelle Andersen-Harild" said Jan Bolding of the Copenhagen Bird Ringing Centre after the unusual find.

Facts about the swans

The mute swan is distributed throughout most of western and central Europe, with the largest population being found in the British Isles. The northern limit for the mute swan's European distribution runs through southern Norway, the middle of Sweden over to the most southerly Finnish skerries. In addition the mute swan is also found in south-eastern Europe and right over to the Black Sea, the Caspian Sea and Kazakhstan.

In the middle of the 1920s the breeding population of mute swans had all but disappeared from Denmark, but the number of birds increased rapidly after they were protected in 1926. Today mute swans breed throughout most of the country and are most numerous on the islands. The first mute swan colonies were seen in Denmark in the mid 1950s (Andersen-Harild 1978), and today over half of the Danish population breed in colonies. The Danish waters house large numbers of mute swans both in the summer during the moulting season and in the winter (Andersen-Harild 1971a, Pihl et al. 2001).