Action: Use copper strips to exclude snails from nests
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A single small, before-and-after study in Mauritius found no snail-caused chick mortality in 2004–7 after the installation of copper strips at seven echo parakeet Psittacula eques nest holes, compared to four fatalities in 2003–4.
In Mauritius, the critically endangered echo parakeet Psittcaula eques has a very small breeding population and low reproductive output. In 2002–4, four chicks were found dead having been covered in slime and suffocating after African giant land snails Achatina spp. (introduced to Mauritius and many other islands for food) moved other them.
Snails are deterred from moving over copper due to a reaction between their slime and the metal, and trials in Mauritius showed that Achatina individuals did not move over copper strips. A snail exclusion barrier was therefore tested.
Supporting evidence from individual studies
A small before-and-after study in a forest in Black River Gorges National Park, Mauritius (Tatayah et al. 2007) found that African giant land snails Achatina spp. did not enter seven nest holes used by echo parakeets Psittacula eques between the 2004/5 breeding season and 2007 following the installation of a 50 mm wide strip of copper around the trunk of each occupied tree. Before copper strip installation, four chicks were found dead in two nest holes between 2003 and 2004 due to asphyxiation by snail slime on the snail’s foot.