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Monday, October 22, 2012

Saving species with scent

Catherine Price and Peter Banks from the universities of New South Wales and Sydney may have found a way to protect endangered native species from predators. It seems that predators are less likely to find and kill prey if the hunters have been pre-exposed to the scent of that prey. At least, that was the case for black rats hunting quails’ eggs.

The experiments were conducted in one-hectare square grids in shrubby areas known to contain large black rat populations. These rats were more than happy to raid birds’ nests for eggs or nestlings, though they had not previously encountered quail. The researchers introduced the scent of quail nests (more specifically, feathers and feces) to the test areas. In some cases, the scent was spread around for seven days after which artificial nests containing actual quail eggs were introduced. In other tests, the scent and the nests were imported into the rats’ territories at the same time.

In regions where the quail smells were introduced a week prior to the nests, quails’ eggs had a 62% greater survival rate. In other words, after prolonged exposure to quail smells that were not associated with nests, the rats ceased hunting for quail eggs. In essence, the rats were being taught to ignore quail nest smells.

How would this help in a real world setting? While ecologists probably can’t continuously pipe prey smells throughout natural parks, they might be able to do so for a few days prior to a planned reintroduction of an endangered species. This might give a vulnerable species a head start on reestablishing itself in the region.

Price, C., & Banks, P. (2012). Exploiting olfactory learning in alien rats to protect birds' eggs Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1210981109