Black sun is one of nature's most marvelous phenomena, with huge flocks of starlings dancing ballet in the sky before they calm down for the night. The phenomenon can be seen in several places in the wading sea area, but the largest flocks can be found in Tøndermarsken, where the starlings have joint accommodation in the large reed forests along Vidåen.
The experience of black sun is never the same. Sometimes the starlings come to the accommodation in smaller flocks, which easily descend into the reed forest. Other times, the flocks gather into one flock, which gets bigger and bigger, all while forming amazing, organic shapes in the evening sky. Sometimes the starling herd can become so large and compact that it completely shadows the setting sun – that's how the phenomenon has got its name.