In April 1994, a prefab breeding site for Sand Martins was installed near the town of Meppel (52°42’N, 6°12’E). The concrete wall is 5 m high and 90 m in length, offering 488 holes in four rows (from bottom to top respectively 58, 90, 168 and 172). The wall faces to the southwest (Photo). Sand Martins ignored this artificial breeding opportunity in 1994 and 1995, but 95 pairs settled in 1996. The distribution of nests per row was significantly different from random: from bottom to top respectively 0, 0, 13 and 82 nests occupied. The majority of pairs (78%) nested in the most quiet section of the site.