Black Sun Denmark is a nature phenomenon in the marshlands in southwestern Jutland, Denmark, in particular the marsh near Tønder and Ribe, near the border to Germany.
Approximately one half an hour before sunset, very large numbers of migrational starlings (sturnus vulgaris also known as the European Starling) gather here in spring and autumn when they move between their winter grounds in southern Europe and their summer breeding grounds in Scandinavia and other countries near the Baltic Sea.
The starlings birds gather in large flocks and form huge formations in the sky just before they decide for a location to roost for the night. The movements of the formations have been likened to kind of a dance or ballet and the bird flocks can be so numerous that they can block the sunset, therefore its name term “sort sol” (Danish for “black sun”).
The starlings location for the night changes all the time, but the same spot can be used two nights in row. When the locations change is it because the birds try to fool potential predators. It is when the predators attack the starling flock that the spectacular ballet-like cataract formation occurs. However, not every night, the predator is present.
This spectacular show is often seen twice a year, March to April being the first, while the second one takes place during October to November.
The largest black sun experiences will usually be in late March / early April and September / early October.
Black Sun period in the spring is shorter than in the fall. This does not mean that Black Sun experience is less than the fall. Often there are more starlings at once, because the period is shorter.
In the marsh near Tønder, a black sun can occasionally comprise a formation with up to one million birds. The best time a year to see the black sun phenomenon is mid-October.
Read also: Skagen Town – Top Denmark
The large flocks of starlings are a big attraction in Denmark that attracts thousands of people to the marshes each year and its a must see for any bird-lovers.
Video by Michael Rying
Video by WaddenSeaCentre, Denmark
Where can you see the Black Sun
The best spots to see “sort sol” is at Magisterkogen south for Tønder or at lake Rudbøl the area is also called Tøndermarsken. See the map below.
Another good location to see the phenomenon is in Ribe about 50 km north of Tønder.