Protect nests and nesting sites from predation using conditioned taste aversion
Overall effectiveness category Awaiting assessment
Number of studies: 1
Background information and definitions
Conditioned taste aversion involves placing chemicals on or near either real or artificial eggs or nests. The chemicals used may be distasteful or cause sickness or other gastrointestinal discomfort, but at a dose not intended to cause long-term harm to the animal. The intention is to create an association between the eggs and the unpleasant chemical, thereby reducing predation of reptile nests.
For other uses of conditioned taste aversion, see Use conditioned taste aversion to prevent carnivorous reptiles from eating toxic invasive cane toads.
Supporting evidence from individual studies
A replicated, randomized, controlled, before-and-after study in 1993–1994 on a long sandy beach in Florida, USA (Ratnaswamy et al. 1997) found that conditioned taste aversion using artificial nests with unpalatable eggs did not reduce predation of loggerhead turtle Caretta caretta nests compared to areas where no taste aversion was attempted. The number of nests predated in areas with taste aversion were similar (46% and 36 % of 246 and 390 nests) to the number of nests predated with no treatment (31% and 24% of 231 and 379 nests). Additional nests in the taste aversion area that were also covered with a wire screen were predated less than nests receiving just taste aversion (16% and 12% of 531 and 720 nests), but a similar amount to nests receiving no treatment. Consumption of artificial nests were statistically similar before (42–70% of eggs eaten), during (50–60%) and after (67–70%) taste aversion treatment. In 1993–1994, a long stretch of barrier beach (37 km) was broken down into four experimental blocks, and around 2.5 km of each selected for conditioned taste aversion. Nests in the remainder of the block either received no treatment or were part of further tests of the effect of nest screening or raccoon Procyon lotor removal. Fifteen artificial nests were placed in each taste aversion area consisting of 10–15 chicken eggs placed on the sand surface. Egg consumption was monitored during a pre-treatment phase (8 nights, untreated eggs), a treatment phase (8–9 night, eggs injected with 10 mg oral oestrogen) and a post-treatment phase (5 nights, untreated eggs), with eggs replaced daily. Turtle nests were monitored 2–4 times/month in 1993 and 2–3 times/week in 1994.Study and other actions tested