The Sandwich tern and organochlorine compounds

As a result of the discharges of environmentally hazardous substances in the 1960s, numbers of Sandwich tern have plummeted. In spite of a recovery, the species has not yet regained its former numbers.

Trends

Around 1900, colonies of Sandwich tern used to be plundered for the feathers, which were used to decorate ladies' hats. After 1908, when the bird became a legally protected species, the population was able to expand, reaching 30 000 to 40 000 breeding pairs in the 1930s and 1950s. During World War II the population fell by more than a half - to less than 15 000 breeding pairs - because people collected the eggs for food.

Around 1960 the numbers of breeding pairs of the Sandwich tern fell sharply as a result of poisoning from the discharges of organochlorine compounds in the Nieuwe Waterweg - particularly after an accident in 1963. In 1965, only 900 breeding pairs remained. After the discharges were halted the number of breeding pairs started to rise again, reaching over 14 000 in 2001. But the 1950 figure is still a long way off. What seems to be limiting the size of the population is the amount and quality of food.

The species breeds on sparsely vegetated sandflats in the Wadden area and the Zeeland delta. The largest colonies are on Griend, Hompelvoet (Grevelingen) and on the Hooge Platen (Westerschelde).

The Sandwich tern is on the Red List of birds.