Robots threaten hedgehogs in German gardens

Environmentalists and biologists in Germany want to protect hedgehogs with a nighttime ban on robot lawnmowers.

These labour-saving devices pose a real danger to these nocturnal animals which were added to Germany’s “Red List” of endangered species, a study by the Berlin-based Leibniz Institute for Zoo and Wildlife Research has found.

Forty-seven per cent of the 370 hedgehogs that had been injured by the blades of a robot lawnmower and which were studied by the team of investigators either died of their injuries or had to be euthanised, the report disclosed.

The Institute’s Dr Anne Berger explained that hedgehogs were at particular risk because these nocturnal feeders do not flee when they are in danger but instead rely on their spines to protect them and remain as quiet as possible.

Once injured they seek the protection of hedgerows and bushes to avoid attracting the attention of predators and even minor blade injuries can become infected and lead to death.

In an experiment using robots where the blades had been removed, investigators noticed different behaviour patterns and saw that hedgehogs could be classified as “shy” or “courageous” during their encounters with the lawnmowers.  Adult hedgehogs tended to react more shyly than their young, although all behaved less courageously on meeting one for the second time.

The quiet robots have become increasingly popular because they are the only type that may be used at night or on Sundays in Germany, Dr Berger said.

She also pointed out that there was no particular day when very few or very many hedgehogs suffered blade injuries, indicating that weeklong use of the robot mowers was responsible.

The quickest and easiest way to protect hedgehogs, the Leibnitz scientists said, was a ban on robotic mowing at night to prevent their numbers from declining further.

But not only hedgehogs are threatened by the robots.

Corinna Holzel from BUND (Friends of the Earth Germany) also called for a ban, saying that ban on nighttime mowing was the “minimum” that was needed.

“It would be better still to do without robot mowers entirely,” Holzek told the DPA news agency.

The robots were a danger to biodiversity because they were unable to judge what should not be removed from lawns.

“They cut down every daisy, which means that bees, butterflies and insects lose important food sources.”

Nevertheless some smaller municipalities have already announced bans on nighttime mowing while the major city of Cologne is also considering restrictions.