De Oeverzwaluw Riparia riparia in Drenthe in 1989- 2000 en verder

The population trend of the Sand Martin in Drenthe is given for the period 1989-2000. The species showed distinct ups and downs, mostly related to droughts (decline) and high rainfall (increase) in the Sahelian region (Fig. 1). Most colonies in Drenthe are -muchsmaller than 100 pairs (Table 1). The species is almost entirely dependent on man-made cliffs, mainly sand quarries; only 1.2% of all pairs in 1989-2000 bred in natural sites along streams. Several recommendations are proposed for the future management of sand quarries in relation to Sand Martin colonies, especially regarding the closing down of several large quarries in the near future.