It was the first of its species to successfully hatch in a European zoo.

Later researchers found evidence that the eggs in question successfully hatched.

In related species, cysts many decades old have been successfully hatched.

"If they hatch successfully, and I think they will, we could have a lot of foliage damage."

The species has done well, but due to the need for moving water to successfully hatch eggs, must continually be stocked in the lakes.

Incubation takes 14 to 15 days, a day less in later broods, and an estimated 94% of eggs hatch successfully.

About two thirds of eggs hatch successfully, and a third leave the nest as fledglings.

Both eggs hatched successfully and the chicks are fit and well.

The average brood size of nests where eggs hatched successfully was 8.33 hatchlings.

In 2012 a new nest was reported in Snowdonia, and a single chick hatched successfully.