Translated from Dutch Vroege Vogels radio, 15 August 2018; about nature reserve De Putten:
In the first year (2016), 104 [Sandwich] tern couples nested on the [new artificial] islets. In 2017, the number grew considerably: 2,100 couples were counted. But this year exceeded all expectations: this summer no less than 3,400 breeding pairs were counted. Besides the high number of pairs of terns there was also a large breeding success. From each breeding pair, 0.7 chick was raised. An excellent score for the Sandwich tern.
Together with Texel, this area located behind the Hondsbossche Zeewering dike now houses half of the European population of Sandwich terns. Ranger Marcel Groot of Natuurmonumenten is very pleased: “It has gone so fast. We would also have been very satisfied with two or three hundred breeding pairs but now there is a zero behind it: three thousand pairs.”
In addition to the Sandwich tern, the Harger and Pettemer polder also is home to, eg, the rare lesser white-fronted goose and on the islands also ringed plover, redshank, black-headed gull and common tern breed.