Biscuit the emu is hoping for a bumper Easter surprise as he sits on a clutch of giant emerald green eggs, which are due to hatch out any day at Longleat Safari Park.

If the eggs do hatch successfully, it will be a first for the Wiltshire wildlife attraction and keepers are remaining cautiously optimistic.

Emus are unusual in the fact it is the father who sits on the nest and looks after the chicks when they hatch.

As well as the eggs in Biscuit's nest, they are also monitoring two additional eggs in an incubator and have reported one of the eggs is beginning to rock – a sure sign it is close to hatching.

"The fact that Biscuit is taking his parental responsibilities so seriously and is refusing to leave the nest is a good sign," said Keeper Gemma Short.

"We're very much leaving him alone and letting him get on with things as naturally as possible so all we can do is to wait, watch and hope," she added.

Emus are among the largest birds in the world, growing in excess of two metres tall. They're found primarily in Australia, but also in New Guinea, Indonesia, Solomon Islands, and the Philippines and are part of the ratite family, along with rheas and ostriches.

Mating pairs stay together for up to five months, after which females lay large, emerald-green eggs in expansive ground nests. The males incubate the eggs for about seven weeks without drinking, feeding or leaving the nest.

Emu eggs, which are emerald green in colour, have to be incredibly tough to survive in their native Australia. The emu chick will start by pecking a hole in the egg before expanding his body to break the hard, brittle shell.

When the chicks are fully grown they can reach land speeds of up to 50 kilometres per hour making them one of the fastest land birds alongside their ostrich cousins.

Chicks stay with dad for about four months, until they are able to eat on their own.

Due to the ongoing restrictions with regard to avian flu, the emus are currently being kept inside.