Short abstract from the book: The lesser black-backed gull is a common breeding bird in
Denmark with an estimated population of 4,000-6,000
breeding pairs. A population of the subspecies fuscus formerly
bred on the Danish island of Græsholm in the Baltic Sea,
but this population became extinct in the 1990s. Today, most
of the Danish breeding population belongs to the subspecies
intermedius. The lesser black-backed gull is a common passage
migrant in April-May and August-September.
In Denmark the first lesser black-backed gull was ringed
in 1927, with the majority ringed in the 1930s and between
the 1960s and 1990s. The greatest number were ringed in 1973 (1,060). Seventy-five per cent of the recovered birds
were ringed on the island of Anholt in Kattegat, 13 % on
Græsholm and 5 % on Hirsholmene. Most birds were ringed
as chicks in June-July.
The fuscus birds from Græsholm left the colony in August-September. Some birds were recovered in the inner Danish
waters during autumn, but the majority migrated S in
September. Two alternative routes were used: one due south
through central Europe, and one SW via the Black Sea.
The routes seemed to converge in the eastern Mediterranean
(September-October). Some birds wintered in this region and
others continued to Lake Victoria in East Africa, where the
earliest bird was recovered on 10 October. A few birds ringed
on Græsholm have been recovered in West Africa south of the
Sahara.
Most of the gulls ringed in other parts of Denmark belong
to the intermedius subspecies. These birds disperse from the
colonies in August, with the autumn migration starting in
September. The majority migrate through the English Channel
and along the European west coast to the Iberian Peninsula,
which they reach in mid-October. Some birds winter along
the coastal sites of the Iberian Peninsula, while others continue
to West Africa from where birds have been recovered from
Morocco in the north to Ghana in the south. Some of the gulls
take a more southerly route through the European continent
to winter sites in the Mediterranean. Two brood mates that
hatched on the island of Saltholm in Øresund migrated in
two different directions: one was recovered in the southern
part of the Netherlands in autumn, the other was recovered
in Tunisia in winter.
The spring migration takes place in March-April, and lesser black-backed gulls seem to reverse the routes used during
autumn. Outside the breeding season, gulls from Norway,
Sweden and Finland have been recovered in Denmark. The
first visitors arrive in August, with the number of visitors culminating in September. The majority of the visitors have left
the country by the end of October. Eighty-one foreign lesser
black-backed gulls from Britain, Sweden, Norway, Belgium
and the Netherlands have been recovered in Denmark in the
breeding season, some as adults in the colonies.
Read more about the species in the chapter from The Danish Bird Migration Atlashere
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