Every year in spring and autumn, up to one million starlings migrate from Norway, Sweden and Finland, and on their way to France, Britain, Belgium and the Netherlands they create one of the most unique natural phenomena in Denmark.
The Black Sun, or ‘Sort Sol’ as the Danes it call it, occurs in southwestern Jutland in Denmark during autumn from August until the end of October, and in spring from the middle of March to the middle of April – when the starlings returning to the north make a stop at Wadden Sea National Park’s marshlands to rest and find food.
The spectacular phenomenon lasts for about 20 minutes during sunset and it has taken its name due to the fact that during this time, it feels like the sun disappears behind the hundreds of thousands of birds that fly in the sky over Denmark.
What makes this natural phenomenon even more impressive is that before the starlings land, the flocks perform movements that those who have seen it up close compare to dancing. Starlings choose to move together and perform various formations in order to protect themselves from predators. So, one of the the best moments for someone to see the Black Sun is when the birds begin to land to spend the night. In their attempt to safeguard themselves from raptors such as eagles and hawks, starlings start flying in synchronized patterns. So to people who watch it from the ground, it appears the flocks are changing shapes every minute. Starlings travel in such large flocks to stay warm and exchange information about the best feeding spots.
Even though Sort Sol paints Denmark’s sky both in the spring and in autumn, the largest gathering of birds is from the end of September to mid-October, when after eating and resting the birds head south in search of warmer climate.
Wadden Sea National Park in Denmark attracts thousands of visitors throughout the year but when it’s time for the Black Sun, the number of people visiting the park peaks at around 100,000.