Saving the Endangered European Ground Squirrel by Relocating Colonies to Airports

The European ground squirrel, also known as the European souslik, is an endangered species that has seen its population decline by over 99% in many countries. However, it has managed to thrive at airports, likely due to the open grassy areas. A rewilding project by conservationists is working to save the species by trapping colonies at Bratislava Airport in Slovakia and relocating them to other airports around the country.

The Plight of the European Ground Squirrel

The European ground squirrel (Spermophilus citellus) is a small rodent that lives in colonies in open grasslands. Up until the 1960s, it was abundant across Central Europe. However, industrial agriculture and the loss of pastures and meadows caused populations to plummet. For example, in Slovakia its numbers declined by 99% in under 50 years. It is now endangered and on the IUCN Red List.

Why Airports Became a Refuge

As natural grasslands disappeared, the squirrel managed to survive on the edges of fields and in pastures. Oddly, some of the only remaining strongholds are at airports. Bratislava Airport has one of the largest populations left in Slovakia. Researchers believe the squirrels thrive there because airports offer plenty of open, short grassy areas the squirrels need for visibility and communications.

Relocating Colonies to New Airports

To save the species from extinction, conservationists are trapping colonies from Bratislava Airport and releasing them at other airports around Slovakia to establish new populations. So far, over 800 squirrels have been relocated. The project carefully selects release sites at smaller airports that offer suitable habitat.

Trapping and Relocation Process

The project uses live traps placed by squirrel burrows at Bratislava Airport. Trapped squirrels are transported to new airports and released into vacant burrows, allowing the squirrels time to adjust before emerging to explore their new home. Each squirrel is marked with fur dye before release for monitoring purposes.

Why Conservationists Choose Airports

Airports make ideal release sites because they provide the right habitat conditions the squirrels need, such as short grassy areas. Establishing multiple separate populations also helps improve genetic diversity and resilience. Allowing colonies to thrive at human-created sites like airports helps ensure the species’ survival while natural habitats recover.

Importance of the European Ground Squirrel

While they may seem like just another rodent, European ground squirrels play a key ecological role. Their colonies provide habitat for other species like bees, wasps, and lizards, who nest in vacant burrows. They also aerate soil and spread seeds. Saving the species preserves these benefits.

A Cautionary Tale

The squirrel’s plight mirrors that of the passenger pigeon in North America. Passenger pigeons were once the most abundant birds, but were hunted to extinction by 1914. The European ground squirrel shows there’s still time to intervene and preserve biodiversity. Airport colonies serve as an “ark” during these difficult times.

Rewilding Efforts by Conservation Groups

The Bratislava Airport project exemplifies rewilding, an approach focused on restoring and protecting natural processes to allow nature to recover. It is led by Slovak conservation group BROZ in collaboration with rewilding organization Mossy Earth. The project will establish 15 new colonies and reinforce 25 existing struggling colonies across Slovakia by 2027.

How the Public Can Help

Conservation rewilding projects rely on public support. Organizations like Mossy Earth are funded through member contributions to continue this important work saving endangered species. Readers who wish to help can join as monthly members on Mossy Earth’s website.


While an unconventional conservation solution, relocating the European ground squirrel to airports provides a lifeline for this endangered yet ecologically vital species. As grasslands continue to be restored, the squirrel populations established at airports can be used to recolonize new suitable habitat areas. This innovative airport colony approach is ensuring the species avoids total extinction.