Austral storm petrels, or southern storm petrels, are seabirds in the family Oceanitidae, part of the order Procellariiformes. These smallest of seabirds feed on planktonic crustaceans and small fish picked from the surface, typically while hovering. Their flight is fluttering and sometimes bat-like. Historically, they were grouped together with the Hydrobatidae in an encompassing storm petrel group, though genetic testing found them to be distantly related, and so they were split.