BS8 Archipelago birds

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Development

The populations Finnish of archipelago birds have mostly been increasing since their systematic monitoring was begun the 1930s. At their peak at the turn of the millennium an estimated total of 500 000 duck, gull, tern, auk and wader pairs bred along the Finnish coastline. This figure is ten-fold compared with the breeding pair number of the 1930s. The number of species has also increased from 25 in the 1940s to 32 at present. Recent years, however, have seen a decline especially in the number of ducks. This is mainly due to the decline of Common Eider, which is by far the most numerous of the sea duck species.

The current population of Common Eider has been estimated at 80 000 to 100 000 pairs. More detailed data exist on Common Eider since 1986. During the past two decades the trends of Eider populations have been quite different in different parts of the Baltic Sea. In southwest archipelago the numbers of Eiders increased until the end 1990s and started to decline quite steeply after that. In the Gulf of Finland Eider numbers have been declining steadily since 1986. The combined index for all populations increased moderately until the late 1990s and has started to decrease since. Especially the last few years show alarming trends.

The overall development of Gull populations has been mostly stable although there are notable differences between species. Common Gull populations have clearly increased since 1986 whereas the Lesser Black-backed Gull populations of have decreased quite dramatically. The steepest decline of latter species took place already at the beginning of monitoring period and the 1990s and 2000s have been almost stable. Herring Gulls and Great Black-backed Gulls show year-to-year variation without clear trends.

Archipelago birds