Saturday 5 May 2018

RARE MOTH TO PARK

This tiny caterpillar of the nationally rare Fishers Estuarine moth was on its way on Wednesday 2nd from Colchester Zoo to the introduction site at Cudmore Grove where there's lots of hog's fennel for it to eat. This caterpillar was safely transferred onto a clump of hog's fennel at the park. The caterpillar is tiny at only about 3mm, it was the first one already hatched out whilst being bred at the zoo.
I had a call from Zoe Ringwood the Natural England project leader for the moth, just the day before to say the warm weather was helping the eggs quickly develop and they needed putting out on site.

The female moth lays her eggs inside a sheath of grass the previous autumn. After overwintering, the eggs start developing and the tiny larvae soon hatch out in the spring, ready to start looking for hog's fennel plants to feed on. Seven separate blades of grass with eggs were collected from the Zoo where they'd been reared over the winter.

Each blade was taped to a cane which was stuck into the ground among a clump of hog's fennel at the park.

The hog's fennel plants were first planted at the park in 2007 especially in readiness for the Fishers Estuarine moths and have been allowed to flourish in the long grass and now total over 1000 plants. The first batch of eggs from the Zoo were brought to the park last spring and although there were no adults seen flying in the autumn, there had been signs in the summer of some caterpillars successfully feeding inside the fennel stalks.

Glen Fairweather has been the moth's custodian at the Zoo and has been managing the project for ten years. Here the plastic containers with the egg batches on grass stalks, were being prepared for transit to Cudmore Grove. Some of the other batches were destined for the National Trust site at Copt Hall.

Forty small wooden and wire enclosures were specially built at Colchester Zoo for the rearing of the Fishers Estuarine moth. The area is not open to the general public and is a bio-secure zone.

Each enclosure has a batch of moths being reared in it, some with the hog's fennel in big plastic tubs.

The moth only occurs in the UK on the north-east Essex coast and a small colony in Kent. Its only food-plant, the hog's fennel is threatened by rising sea-levels, so the big project of planting lots of hog's fennels and the breeding programme with the zoo has managed to successfully establish more populations in north Essex set back from the coastline.

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