In this study, the nesting site characteristics and nest densities of ardeids (grey heron: Ardea cinerea; night heron: Nycticorax nycticorax, and little egret: Egretta garzetta) were investigated in Nallihan Bird Sanctuary. It was found that the site of breeding colony had 166 trees consisting of willows (92) and poplars (74); 105 of which (63 willow and 42 poplar) were found occupied by ardeid nests. In the sampled trees (n = 40), 395 nests (night heron: 254, grey heron: 103, and little egret: 38) were located; 244 of which were located in willows (night heron: 170, grey heron: 44; little egret: 30) and 151 (night heron: 84, grey heron: 59; little egret: 8) in poplars. Also the number of nests and nest density for the 105 occupied trees were calculated as 1037 and 0,027 nest/m(2), respectively. However, the difference between willows (4.07 +/- 3.54 nest/tree) and poplars (2.52 +/- 2.04 nest/tree) in terms of nest densities of ardeids were statistically insignificant.