‘Stress and wash’ may make great crested Triturus cristatus and smooth newts Lissotriton vulgaris palatable for grey herons Ardea cinerea, with a link to video evidence

T he smooth newt Lissotriton vulgaris is a widespread amphibian species widely distributed across western Europe, and notably common throughout most of Great Britain (Speybroeck et al., 2016). Growing up to 11 cm in length, L. vulgaris occupies a diverse range of aquatic and terrestrial environments. In contrast the great crested newt Triturus cristatus, Britain’s largest newt species reaching 16 cm in length, is found predominantly in deeper and more mature fish-free environments across northern Europe (Beebee & Griffiths, 2000; Speybroeck et al., 2016). In England, both species return to ponds to breed typically in February, and then in about June they leave water for terrestrial habitats, while the metamorphs leave water bodies later (Beebee & Griffiths, 2000). Triturus cristatus is known to produce defensive toxic secretions from glands within its skin, which are used to deter predators in combination with corresponding aposematic colouration (Kupfer & Teunis, 2001). The toxic secretion is often seen as a white foamy liquid that is released when the newt is agitated. It is known that the skin secretion of T. cristatus contains a heavy (long chain compound) proteinaceous toxin (Jaussi & Kunz, 1978) and that in both species there are low concentrations of tetrodotoxin and 6-epitetrodotoxin (Yotsu-Yamashita et al.,2007)…