The delicate, red-beaked Arctic tern (Sterna paradisaea) is one of the most typical terns found in Helsinki, as is the slightly sturdier common tern (Sterna hirundo), which can be identified by its black-tipped beak.
Common terns can often be seen standing on the rails of the bridge connecting the Pihlajasaari islands, scanning the waters for small fish. Both tern species nest on the small islets surrounding the Pihlajasaari islands.
Terns do not arrive in Finland until May. The chicks learn to fly by July, and in August all the terns disappear to the south. Terns migrate south of the equator, with Arctic terns migrating as far as the seas surrounding the south pole, where they can enjoy the summer while it is still winter in Finland. The Arctic tern migrates further than any other species in Finland.