2016 Volume 19 Issue 1 Pages 67-78
Artificial nests for raptors have often been constructed as environmental conservation measures in nationwide development projects. This study aimed to identify effective techniques for the setup and promotion of artificial nests for rare raptors through analysis of data from previous road projects. The data showed that 173 artificial nests were set up for 8 species of rare raptors in 31 road projects. These species included the goshawk (119 nests in 17 projects), hawk eagle (20 nests in 7 projects), buzzard (9 nests in 3 projects), osprey (4 nests in 3 projects), falcon (7 nests in 2 projects), grey-faced buzzard (7 nests in 2 projects), white-tailed sea eagle (5 nests in 1 project), and honey buzzard (2 nests in 1 project). Artificial nests were categorized into 6 types based on the materials used (natural or non-natural) and location of the nesting site (tree canopy, top of the tree, or other). The utilization rate after setup was the highest in cases of relocation or reuse of nest-building materials from old raptor nests. Nest height and positioning did not appear to affect utilization rates. However, the results suggest that the distance between artificial and former natural nesting sites is an important factor. In the case of the goshawk, the utilization rate of artificial nests increased when target pairs were relocated less than 250 m from their old nests. In addition, some non-target pairs (i.e., new pairs) began to breed in the artificial nests if the distance was greater than 1500 m. The results also showed that the time elapsed from setup of the artificial nests to utilization by target pairs was generally several years, and that adaptive managements may shorten this time. We suggest that these results support the use of artificial nests as raptor conservation measures in the future.
