Swans hooked on poppies have become so high they can no longer fly or even walk, wildlife experts in Slovakia have revealed.

The birds have become so doped they no longer care about migrating and spend all their time gorging themselves on blooms in the country’s vast poppy fields.

Conservationists say they have been forced to rescue the addicted swans and put them through cold turkey detox to wean them off the plants.

The bizarre crisis began when migrating swans landed at poppy farms near the village of Komarno four months ago (February) and refused to leave.

Dozens of birds have reportedly overdosed and died, while others are so high they are easy game for predators.

Many are found simply lying on the ground like junkies unable to care for themselves.

Slovakia is one of the largest poppy producers in the world and exports hundreds of tonnes of the dried seeds to be used by chefs and cooks.

The birds have reportedly caused more than EUR 10,000 (GBP 8,600) of damage to one family’s fields after destroying approximately five hectares of the crop.

Poppy farmer Balints Pam, from Komarno, told local media that he had never seen anything like it.

He said that about 200 swans had invaded his fields and had refused to leave.

He explained: “Every part of the poppy plant, aside from the seeds, is poisonous. The swans, on the other hand, are ignorant of this and hurt themselves.”

The swans, a protected species in Slovakia, were able to roam freely in the fields because it took four months for the owners to get permission to take them away.

Hundreds of swans reportedly arrived in February after a lake formed in a field as a result of heavy rainfall.

Swans usually eat rapeseed and are thought to have got hooked on poppies by mistake.

Surviving swans are now being taken away by conservationists and relocated far away from the fields to get them free of their addiction.

Consuming poppies results in a narcotic intoxication, with some strands of poppy cultivated to make opium, which can then also be turned into heroin – both illegal Class A drugs.