Reduce predation by translocating nest boxes
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Background information and definitions
Many predators optimise their hunting by searching areas where they have previously been successful. This potentially makes birds nesting in nest boxes vulnerable – they cannot move nesting sites and can lose their clutches year after year if a predator learns their location. Moving nest boxes between years may, therefore, reduce predation and increase reproductive success. This is not the same as translocating birds from an area of high predation to a safer location. Studies describing this intervention are discussed in a separate section within ‘General responses to small/declining populations’.
Supporting evidence from individual studies
A small, randomised and controlled cross-over study from 1975-1990 in boreal forest in southeast Norway (Sonerud 1993) found that relocated Tengmalm’s owl Aegolius funereus nest boxes were predated less by European pine martins Martes martes than unmoved boxes. Nest boxes moved in 1983 by 50-200 m suffered significantly lower predation in 1984-5, compared to before relocation (1975-83), or to control (unmoved) boxes (40% of five nests predated after relocation vs. 100% of 13 nests before and 83% of six controls). Treatments were reversed in 1988-90: the 14 control boxes moved by 110-370 m and previously moved boxes were kept in the same place. Predation rates on newly moved boxes fell (0% predation for four nests after relocation vs. 77% for 22 nests in 1975-85). No statistical comparison was possible with boxes moved in 1983, as only two nesting attempts were made in 1988-90 (of which one was predated).Study and other actions tested
A replicated, controlled study from 1995-1998 in oak Quercus spp. forests in west central Italy (Sorace et al. 2004) found that predation on nest boxes by European pine martins Martes martes increased significantly with age, with 76% of clutches being predated when boxes were six years old. Relocating nest boxes to 800-2000 m away significantly reduced predation rates, compared to nest boxes moved by approximately 100 m (10 of 188 clutches and 37 of 147 clutches predated respectively).Study and other actions tested