The beach is not even officially open yet, when towels are already being laid down figuratively. Not by humans, but by sand martins. The birds have nestled in a steep wall of sand near the city beach.
The little birds come and go. One sand martin flies into a hole and another flies out again. Dozens of holes are visible in the steep wall of sand.
“There are certainly about forty,” says bird watcher Douwe Greydanus. A while ago he received a report from a local resident that they were nesting there. “I then rang the bell. The contractor then cordoned off the area so that the birds can rest.”
The sand martins nest in colonies and dig tunnels in steep walls of 120 centimeters. They mainly do this in natural banks, excavations or sand depots. Their nests are protected during the breeding season. “As a contractor you have to pay close attention, because once they start to breed, you can’t disturb them anymore.”
sheet pile claimed
How do they suddenly end up on the city beach? “The birds like fresh water where there are insects, where they can hunt. They probably just got to the city beach and saw a steep wall and naturally claimed it.”
The birds don’t stay there all summer. The sand martins lay eggs in mid-May, incubating takes 14 to 17 days. There is also sometimes talk of a second leg. “These sand martins may be there until the end of July, early August,” says Greydanus.
Alliantie Markermeerdijken, responsible for the construction of the city beach, says it will not be delayed by the nesting birds.