Ängsö is known for its abundant bird life. In the island’s forests and deciduous groves, there are many trees with cavities that serve as popular habitats for pied flycatchers, nuthatches and various woodpeckers.
The common goldeneye and tawny owl also are prevalent. Coniferous old growth forests offer habitats for white-tailed eagles, ospreys and ravens. The eastern part is a bird sanctuary during the 1/2 – 15/8 period.