The European hedgehog (Erinaceus europaeus) is one of our most beloved wild animals — and one of the fastest declining. In October 2024, the IUCN upgraded the hedgehog's threat status to Near Threatened, as populations have collapsed by over 30% in ten years across many European countries. In Finland, the hedgehog lives at the northernmost limit of its range, making our population particularly vulnerable. In this article, we cover the hedgehog's situation, the threats it faces, and how everyone can help.
Population Collapse Across Europe
The hedgehog population has declined dramatically across Europe. In Great Britain, the rural population has decreased by 30–75% since 2000 and the hedgehog is classified as Vulnerable. In Germany, the population has halved in Bavaria in ten years. In the Netherlands, the hedgehog is classified as Endangered. In Sweden and Norway, the population is estimated to have declined by over 30%. A comprehensive study published in 2025 (Biological Conservation) confirmed that hedgehog populations have decreased in more than half of the European countries where the species occurs. The European Parliament has begun work on creating an EU-wide Hedgehog Conservation Strategy.
The Hedgehog in Finland
In Finland, the hedgehog lives at the northernmost limit of its range — the continuous distribution area extends approximately to the Tornio–Kuhmo line. The hedgehog is protected under the Nature Conservation Act (9/2023). In the 2019 Finnish Red List assessment, the hedgehog was classified as Least Concern (LC), but there is no systematic monitoring of population trends and a decline is suspected. The hedgehog needs at least 155 frost-free days to breed and accumulate sufficient fat reserves for hibernation — Finland's short summer makes this challenging. In Finland, hedgehogs live almost exclusively near human habitation: in yards, parks and gardens.
Why Are Hedgehogs Declining?
The greatest threats are human-caused. Traffic kills hundreds of thousands of hedgehogs in Europe annually — in Germany alone up to one million, in the Netherlands 340,000 and in Belgium 230,000–350,000. Habitat fragmentation with solid fences prevents hedgehog movement. Agricultural intensification, pesticides and insect decline reduce food availability. A Danish study published in 2024 showed that 84% of examined hedgehogs had been exposed to rodenticides and 43% to insecticides. Climate change causes premature awakenings from hibernation that deplete critical fat reserves.
Robot Lawn Mowers — A Growing Threat
Robot lawn mowers have become one of the most significant threats to hedgehogs. In a study published in 2024 by the University of Oxford and the Leibniz Institute, 19 robot mowers were tested — virtually all caused injuries to hedgehogs. In Germany, 370 hedgehogs injured by robot mowers were documented over 16 months, of which nearly half died. The actual number is significantly higher. Hedgehogs are nocturnal, and robot mowers often operate at night unattended — the hedgehog's defense mechanism (curling into a ball) offers no protection against the blades. The most important message: never run robot mowers at night.
How Can You Help Hedgehogs?
Make a hedgehog highway — a 13 × 13 cm hole at the bottom of your fence is enough and allows hedgehogs to move between gardens. This is the single most impactful action. Never run robot mowers after dusk. Leave wild areas in your garden — leaf piles and brush heaps provide nesting sites. Provide fresh water in a shallow dish. Supplementary food can be meat-based cat food (not fish) — never give bread or milk, as they cause diarrhea. Avoid pesticides and slug pellets — hedgehogs are nature's best slug and snail controllers. Always check bonfire sites and leaf piles before burning. Install a ramp in your pond, as hedgehogs can swim but tire quickly.
Build a Winter Nest for Hedgehogs
One of the best ways to help hedgehogs is to build a winter nest, a hedgehog house. In Finland, hibernation lasts up to 8 months — from October to April — and a good nest can determine whether a hedgehog survives. According to guidelines from the Finnish Association for Nature Conservation and WWF Finland, building a winter nest is straightforward:
From untreated boards (NOT plywood — plywood does not breathe and develops mold) build a box of approximately 40 × 40 × 40 cm WITHOUT a bottom — the open bottom lets urine drain into the soil and prevents the hedgehog from freezing to a wet floor. Cut a 10 × 15 cm entrance opening in one wall and attach a 15–20 cm tunnel made from three boards — the tunnel prevents foxes and cats from reaching inside. Drill ventilation holes in both upper corners (to prevent mold). Make the lid removable and cover it with roofing felt for rain protection. Inside, first spread gravel (drainage), then soil, moss, and finally pack the entire space full of dry leaves (maple leaves are hedgehogs' favorite) and hay. Place the nest in a quiet, shaded spot facing north — NOT on the sunny side, as spring sunshine would wake the hedgehog too early. Point the entrance away from prevailing winds. The nest must be ready by the end of September at the latest, preferably by August. Between October and April, do not open or disturb the nest — a nest under snow is warm and safe. Never remove snow from the nest. In spring (May–June), clean the nest wearing gloves, wash with hot water, and refill with fresh leaves.
A hedgehog peeks out from its wooden shelter. Even a simple hedgehog house can save a hedgehog's life in winter. Photo: Alexas Fotos / Pexels.
Detailed building instructions with photos can be found here: Finnish Association for Nature Conservation (sll.fi), WWF Finland (wwf.fi) and YLE Strömsö (yle.fi).
Do you know how to build a hedgehog house and would you be willing to build for others? Contact us — we will connect you with people who need help. Together we can help the hedgehogs of the Vaasa region survive the winter.
Found an Injured Hedgehog?
A hedgehog needs help if it is staggering or lying on its side, active during daylight (a healthy hedgehog is nocturnal), has visible injuries or fly larvae, or is small in autumn (from September onwards) — under 600 g. In early summer, small hedgehogs are often juveniles born in June–July that weigh only 120–350 g when weaned: this is completely normal. But from September onwards, a hedgehog under 600 g cannot survive Finland's long hibernation without help. Pick up the hedgehog wearing thick gloves and place it in a high-sided cardboard box with a towel at the bottom. Provide warmth — a hot water bottle filled with warm water, wrapped in a towel. Offer water and food (cat food). Contact a veterinarian as soon as possible. At Eläinklinikka Saari, we care for injured hedgehogs in cooperation with Nordic Wildlife Care — bring the animal to the clinic and we will provide first aid and arrange ongoing care.
Left: 420 g hedgehog, right: 750 g hedgehog — phone for scale. In autumn, a hedgehog under 600 g cannot survive hibernation and needs help, but in early summer small hedgehogs are often healthy juveniles. Photo: Eläinklinikka Saari.
Hedgehog Life in Brief
The hedgehog is a nocturnal animal that travels 1–2 km per night foraging for food. An adult hedgehog weighs 600–1,100 g and has approximately 5,000–6,000 spines. Its diet consists of beetles, larvae, slugs, snails, worms and insects — the hedgehog is the gardener's best friend. Hibernation in Finland lasts approximately from October to April: body temperature drops from 35°C to as low as 1–4°C and heart rate falls from 190 to about 20 beats per minute. The breeding season is April–September and the female gives birth to an average of 4–5 hoglets. The average lifespan of a hedgehog in the wild is 2–3 years. In Finland, a hedgehog needs a weight of at least approximately 450–600 grams to survive hibernation.
