Ibiza snake crisis as 800 invasive reptiles hunted down

Authorities in Ibiza have declared war on invasive snakes, enlisting local hunters in a coordinated strategy to trap them.

Sant Josep Council, in coordination with other island administrations, is targeting the creatures to protect the island's native lizard population.

The council says it working with the Sant Josep Hunters' Society to "leverage the experience and knowledge of this local group and the availability of their members' lands for placing traps in strategic areas".

The measures have seen snake traps installed in rural areas of the municipality, on lands owned by hunter's society members, to capture as many of the reptiles as they can during their most active period, Diario de Ibiza reports.

Over 800 snakes have been captured since 2021, the council says. The cost of this campaign for this year is €16,999.99 including VAT (£14,292).

But 20 years ago, something changed. The islands had been largely snake-free save for the occasional one that slipped through via freight up until that point.

Scientists, conservationists and the Balearic government say the inundation of snakes began when rich property owners in Ibiza and Formentera began putting ancient olive trees imported from mainland Spain, and further afield, into their gardens.

These cracks and hollow compartments of these non-native trees are perfect for laying eggs and hibernating in, before entering the wild on arrival in Ibiza.

Unfortunately for the lizards, they make up around half of the snake's diet and have been under threat from their appetites, according to the outlet.

The Hunters' Society is a non-profit that manages Sant Josep's hunting reserve, the largest of its kind on Ibiza Island.

In a press release, the council noted that the Spanish Catalogue of Invasive Exotic Species (Article 64 of Law 42/2007 and Decree 630/2013) classifies all snakes of the Colubridae family as invasive species for the islands of Ibiza and Formentera.

Such is the impact of the snakes on the lizard population, that a law was approved last year which includes urgent measures for protecting the Pitiusan lizard (Podarcis pityusensis) - which is classified as threatened, under the vulnerable category - as well as the Balearic lizard (Podarcis lilfordi).

There are also restrictions on bringing certain types of trees to the islands to minimise the risk of snakes slithering out on the island after hibernating inside tree trunks.

Antònia María Cirer, an Ibizan biologist who has studied the reptiles since the late 1970s previously told The Guardian: “The density of the lizard population across the islands used to be very, very high.

“It was extraordinary. There were so many that if you sat down anywhere to eat a sandwich or a piece of fruit, the crumbs would bring the lizards out straight away.”

The group, made up of some 390 members, manages an area of around 9,500 hectares (95 km²) within the municipality.‌

From May to November it will be installing a hundred snake traps, and carrying out regular inspections and maintenance on them.

They're also tasked with caring for the mice used as bait, as well as the removal and management of captured snakes, and removing all the traps at the end of the campaign.

The Hunters' Society will provide a field guard with a vehicle to travel across all terrains where traps have been placed.