This picture was made in the evening at Vransko Lake, in Croatia. These swallows were all landing in the reed, where they were going to spend the night together with martins and starlings.
Vransko Lake is the biggest natural lake of Croatia. The Northwest side of the lake has huge reedbeds, which are home to healthy populations of most of the typical reedbirds. In august hundreds of thousands of Swallows and martins use the reedbeds as sleeping roosts, which causes an amazing spectacle in the late evening and early morning.