In 2020, Christiansø was designated an official nature reserve by the Danish Outdoor Council.
Christiansø is a unique region of Denmark. The history and nature here aren’t found anywhere else in the country, and its waters, which are also part of the nature reserve, are of major significance.Board of the Danish Outdoor Council, December 2019
In 2018, Ertholmene became one of 15 locations in the kingdom to be included in Denmark’s Naturkanon, the official list of the most beautiful places in Denmark, certifying the area as a unique heritage site.
Ertholmene truly is exceptional in Denmark. No matter where you stand on the islands, you will see a breathtaking mix of unparalleled natural surroundings and a unique cultural history.The jury’s justification
The natural landscape at Ertholmene is diverse and varied. Within just a few hundred metres, you can move from wind-swept, rocky coast through shadowy forests to welcoming and idyllic gardens.
Ertholmene’s spectacular natural resources have been protected since 1926. Today, the islands are subject to a range of Danish and international protections of the natural surroundings, the island culture and the local wildlife, and the islands are considered one of the most protected nature reserves in Denmark.
Græsholm, which is closed to the public, is home to one of Denmark’s largest colonies of seabirds. Thousands of herring gulls come here to breed, and the island hosts Denmark’s only colony of razorbill and guillemot. These birds live here because they are left in peace and there is plenty of food in the form of the little herring-like sprat that can be found in large shoals in the waters surrounding the islands. The birds are easy to spot from Frederiksø using binoculars.
On the inhabited islands, there are thousands of nesting eider. You can find them everywhere, even on the busiest streets. The birds are well-camouflaged and trust that the humans won’t bother them.
In spring and autumn, the islands are visited by large numbers of migratory birds, ranging from cranes to goldcrest. You will see the largest gatherings of migratory birds in calm, misty conditions. A total of 302 different species of bird have been spotted on the islands.
The many waterholes on the islands are home to large populations of amphibians. You will find toads, little newts and two quite rare species: the European green toad and the marsh frog.
In recent years, several hundred grey seals have been spotted in the waters around Ertholmene, more than in anywhere else in Denmark. They primarily stick to the rocky islet called Tat, north of Græsholm.