31 Aug 2016
Giant slugs are eating young hatchlings in their
nests, claim two Polish scientists.
The pair, colleagues at universities in Wroclaw and Zielona Góra,
were engaged in a study of common whitethroat birds when they came across a
slug of the Arion genus in a nest of
newly hatched chicks. On returning the next day, the scientists found a nest
full of dead chicks, with injuries suggestive of the slug’s involvement.
“We couldn’t believe that the slug had killed the nestlings,”
Kararzyna Turzańska told New Scientist magazine. “We talked to many experienced ornithologists, but none of them had
observed slug predatory behavior towards birds before.”
However, Turzańska and her
Chachulska discovered that their observation was not the first time such
behavior had been observed. Mainly in Europe, the reports detailed suspected
slug attacks on a number of ground-nesting species.
actual moment of slugs predating on nestlings isn’t easy to observe,” says
Turzańska. “You are more likely to come across the traces of the ‘tragedy’: hatchlings
with injuries, covered in slime, and slug droppings found nearby.”
species concerned are some of Europe’s largest slugs – the roundbacks,
including the so-called ‘Spanish’ slug, Arion vulgaris. This is regarded as an
invasive species and is well-known for its predation on earthworms and even
New Scientist; Journal of
Avian Biology, DOI: 10.1111/jav.01189