On Sunday 18 December 2011, an hour before sunset, no birds in the trees of the small island in the Hofvijver pond in The Hague city centre in the Netherlands.
In the pond, black-headed gulls, mallards, tufted ducks and common pochards swim.
On a bank, Egyptian geese eating grain.
Then, less than half an hour before sunset, ring-necked parakeet sounds.
This is a video about ring-necked parakeets around the Hofvijver.
Small parakeet groups are flying here from all over the Hague. They form bigger groups. Finally, over a thousand birds. At first, many of them congregate in the big trees of the Lange Vijverberg, north of the Hofvijver. Then, they fly to the island. Where they can sleep without dangerous cats. Before they fall asleep, they make lots of noise.
Ring-necked parakeets in Utrecht: here.
Ring-necked parakeets in Flanders: here.
British bird migration timeline: here.