Dijkstra B. & Dillerop R. 2013. Sand Martins Riparia riparia in a colony in northern Drenthe in 2000-13: some ringing results. Drentse Vogels 27: . At an artificial sand cliff in northern Drenthe, the number of occupied Sand Martin nests varied between 60 and 601 in 2000-13. Numbers varied according to the annual availability and suitability of nesting sites. From 2004 onwards, mist nets were used to capture as many birds as possible, resulting in the capture of 497 birds older than one calendar-year and 121 in their first calendar-year. Respectively 5.2% and 2.5% of these birds were recaptured once or several times in later years. Two birds were found breeding in other colonies in later years, i.e. a female ringed in 2010 and recaptured in 2011 (breeding dispersal of 37 km), and a first-year bird ringed in 2008 and recaptured at another colony in 2011 (natal dispersal of 44 km).