Long-term survival and growth of free-living great crested newts (Trituruscristatus) pit-tagged at metamorphosis

Twenty-one late-larval or newly-metamorphosed great crested newts (Triturus cristatus) were implanted with passive transponders (PIT tags) and release d into the wild at their natal pond, in England, in 1996. Body mass at the time of release ranged from 0.69 g to 1.57 g, excluding the tag. Eight of t he tagged newts were recaptured as breeding adults in 1999 (5 males, 3 fema les). Seven of the eight were recaptured again in 2000 (5 males, 2 females) , along with four more tagged animals(3 males, 1 female). The mean annual s urvival over the four years from tagging and release in 1996 to the breedin g season in 2000 was at least 85%. The tagged newts recaptured in 1999 were among the smallest in the breeding population that year, which was consist ent with their being the youngest; this interpretation was supported by the appearance of a new group of similar-sized newts the following year. The g rowth of tagged newts between 1999 and 2000 was consistent with that of the population at large. Overall, we found high mean annual survival and norma l rates of growth among great crested newts PIT-tagged at metamorphosis, in dicating that the tagging procedure we used was benign. This use of PIT tag s, which allow long-term and instant identification of individual animals, provides a means for investigating dispersal, colonization and metapopulati on dynamics during the hitherto little-studied juvenile phase of the life c ycle of this protected species.