Exposing wild black rats to the smell of bird prey seems to put them off prey that is introduced later on — a strategy that could prove useful in species conservation.
To simulate bird nesting odours, Catherine Price and Peter Banks at the University of Sydney, Australia, placed feathers and faeces from quail (Coturnix coturnix japonica) in the habitat of the wild black rat (Rattus rattus; pictured). Seven days later, the researchers introduced artificial nests containing quail eggs. In areas where rats had been pre-exposed to the nesting odours, quail-egg survival was 62% greater than in areas where rats and eggs were introduced simultaneously.
The authors suggest that, during the pre-exposure period, the rats learned to ignore the odour cues because they were not associated with an egg reward.
Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1210981109 (2012)