Species Hedgehog
Hedgehog
- English/Irish names: Western European Hedgehog/Gráinneog
- Scientific name: Erinaceus europaeus
- Number of young: Between 3-6 offspring, generally born around June
- Diet: Mainly slugs, earthworms, beetles, and caterpillars, but quite a generalist feeder
- Habitat: Farmland, scrub, parkland, gardens
- Photo: ©Kevin McCann
Identification
Females:
Length 20-30cm; Weight 0.5kg-1kgMales:
Length 20-30cm; Weight 0.5kg-1kg- Characteristic spines
History of hedgehogs in Ireland
The hedgehog was first recorded in Waterford in the 13th century, where it is thought to have been introduced as a source of food. Despite its non-native status, the hedgehog is considered naturalised in the Irish environment.
Distribution and status
While this species has been little studied in Ireland, roadkill surveys would indicate that it is widespread throughout the country. The Western European hedgehog is the only species of hedgehog found in Ireland. As its name suggests, it is found in West and Central Europe. It has also been introduced to New Zealand.
The European hedgehog is protected under Appendix III of The Berne Convention and under the Wildlife Act (1976) and Wildlife (Amendment) Act 2000. In other areas of its distribution, it has been found to be in decline; in Ireland, it is uncertain whether this is also the case. The current Irish Hedgehog Survey aims to provide baseline data on the distribution and status of hedgehogs in Ireland in order to fill the gap in our knowledge.
The hedgehog is a medium-sized insectivore and is probably one of our most recognisable mammals due to its characteristic spines covering its back and sides.
Spines are absent from the face, chest, belly, throat and legs, which are covered with a coarse, grey-brown fur. Spines are the hedgehog’s main line of defence and, if startled, will roll up in a ball, leaving just a surface of the spines exposed.
As their name suggests, hedgehogs are often found in hedgerows. These habitats, along with scrubland and woodland edges, provide essential nesting sites and support diverse invertebrate populations, offering a vital food source for insect-eating species like the hedgehog.
Unlike other mammals that build a secure permanent home, the day nests of hedgehogs are flimsy structures designed for short-term use. While hedgehogs may occupy a variety of nests during the active period, they do return to individual nest sites. Most day nests occur in hedgerows, but rabbit burrows, abandoned silage bales, stonewalls, and garden sheds can also be used. This adaptability allows them to thrive in various environments, including urban areas. Although hedgehogs can be found in a wide range of habitats, they tend to avoid wetlands and mountainous regions.
Apart from bats, hedgehogs are the only Irish mammals that undergo true hibernation. Due to Ireland’s milder climate, hibernation is shorter than in other regions, typically lasting from October to March. While some hedgehogs remain dormant for the entire hibernation period, others wake periodically and move to a new hibernation site. Hibernation sites are robust structures with a short tunnel leading to a chamber composed of compacted leaves.
In Ireland, male hedgehogs have been recorded to cover an annual range of about 56 hectares, while females cover a smaller area of around 16 hectares.
Hedgehogs mainly eat insects, including caterpillars, earwigs, beetles, spiders, harvestmen, slugs, and earthworms.
Hedgehogs are, however, opportunistic feeders and may also eat frogs, small mammals, birds, eggs and carrion. They spend a lot of time foraging at night, especially in autumn, as they prepare for hibernation.
Hedgehogs breed between April and July, with females often mating with multiple males.
While not territorial, males expand their range during the breeding season to access more females. This increased movement leads to a rise in hedgehog road deaths, with males being the most affected.
Litters typically consist of three to six young, with most births occurring in June. However, in Ireland, young hedgehogs as old as six weeks have been seen as late as October, suggesting that breeding can occur throughout the active season. Some females may have two litters a year, especially if the first litter does not survive.
Newborns stay in the nest with their mother for about a month. Males have no involvement in rearing young. After this period, the mother leads them outside to learn how to forage for two weeks. By six weeks old, they become independent and live alone.
While hedgehogs can live up to ten years, most in the wild do not survive beyond their second year.
A study on roadkill in Ireland found that 54% of hedgehogs killed on roads were under one year old, with males being particularly at risk. Hedgehogs are among the most frequently killed mammals on Irish roads.
It has been suggested that badgers may limit hedgehog numbers in an area; however, in a study in Ireland, both species were found to coexist, with just one hedgehog death attributed to badgers over a three-year period.
In Britain, the hedgehog population has fallen by nearly 50% in rural areas and 30% in urban areas over the last two decades. These trends are due to the loss of hedgerows and marginal habitats to intensive agriculture and increased road traffic. More research is needed to understand trends in Ireland.