The large white-cheeked waterfowl, which look similar to Canada Geese, first appeared in Finland in the 1970s and began breeding here in the early '80s.
According to the Finnish Environment Institute, the geese have adapted well to life in Finland and there are no factors in sight that would limit population growth.
However the number of barnacle geese in the Helsinki area has declined this year. The number of chicks is down by nearly one fifth compared with last year, while the number of adults has declined by a few percent. The Environment Institute says this may be at least partly because of the harsh winter and the chilly early summer.
The largest concentrations of the birds are in the Tapiola section of Espoo and on Helsinki's fortress island of Suomenlinna. Altogether there are about 3,300 barnacle geese in the capital region.