Black sun – starlings flying at Tøndermarksen

One of the most unique natural phenomena’s in Denmark is the display the starlings are performing in the spring and fall. Starlings live in Denmark during the summer when they come to take advantage of the summer and the long days – but they need to go and collect various small bugs to eat. During the long dark winters in Denmark the starlings can’t find enough food in Denmark so they have to migrate to warmer places.

The migration of the starlings involve a long flight for the small birds – some of them actually cross the north sea in a none stop flight to reach the south of England where the winter weather is a little warmer. To be able to fly for such a long distance the starlings need to fill up first – they stop at the west coast of Denmark to eat eat eat. They need to put on weight a total of 60 grams. This may not sound like a lot but it is actually doubling the weight of the individual bird.

To eat this much they stay around the low lying wetlands of Tøndermarsken for a while. The flocks of starling in this area in the fall reach up to a couple of millions birds making it the largest collection starlings in the world.

During the day the birds are spread across a large area to search for food – they actually need to keep a little distance to the other birds when they are feeding. So during the day you only see a few starlings at the time. This change during the night. The starlings like to sleep in a large group for security reasons.

When we reach nightfall the starlings come together in a huge flock counting up to hundreds of thousands birds. The bird goes to sleep in some straws next to a little lake just south of the Danish border with Germany.

We go to the area to spot the birds in the hour before darkness and they come to the straws in different sized groups many of which consist of tens of thousands of starlings. We have seen movies of the starlings making shapes in the sky. These shapes the starlings make before they go to bed is called sort sol in Danish or black sun since the shapes can resemble the shape of the sun. The reason the starlings fly like this is to avoid birds of prey wanting to have a little evening snack. I thought this would be easy to spot during the fall with the large flocks of starlings – but apparently it is more common to see this during the spring.

Unfortunately there were no hungry birds of prey this evening so the starlings went down in the straws quickly. When the starlings went down they did it in high speed making a schoosh sound when they dived down. It was amazing how fast they could dive and still manage to stop before they hit the water a few inches below the spot they stopped.

It was a fun experience to see this many birds in a night – and maybe it would be worth heading back in the spring one year when the border to Germany will reopen.