Hedgehogs, Erinaceus europaeus, and How to Help Them.

by Judith John.

Hedgehog in the suburbs.  Photo by Bill Welch.
Hedgehog in the suburbs. Photo by Bill Welch.

Hedgehogs are solitary animals except when raising young. They are nocturnal and during spring, summer and autumn spend the daytime sleeping in nests of leaves, waking at dusk to hunt for soil invertebrates such as slugs, snails, beetles, earwigs, worms, caterpillars, and millipedes. They have poor eyesight, relying more on an acute sense of smell, touch and hearing and may travel over 2 kms in one night searching for food.

They mate in April then the male leaves the female. She gives birth to 3-5 blind, pink young about month later in a special maternity nest of leaves and grass. The babies quickly develop soft white spines, open their eyes at about 14 days old and grow more brown spines. Their mother takes them out on their first foraging trip at about 4 weeks and continues to suckle them until they can hunt for themselves. By 6 weeks they should be independent and will leave the nest area.

Hedgehog photo by Judith John.
Hedgehog photo by Judith John.

In winter (November-mid March) when less food is available, hedgehogs hibernate in a nest of dead leaves and grass beneath deep leaf litter in woodland or beneath hedgerows, scrub or even garden sheds. Their body temperature drops from about 35 C to 10 C or less, their heart rate slows from about 190 beats per minute to about 20, and their respiration rate to 1 breath every few minutes. If they weigh less than 450gms (1 lb) they will not survive hibernation, so if you find a small hedgehog in autumn advice should be sought from a local expert or the British Hedgehog Preservation Society at www.britishhedgehogs.org.uk

An adult hedgehog has 5,000-7,000 spines. When threatened it raises its spines and rolls into a tight ball. If it isn't quick enough, a dog, fox or even a cat can grab its back legs and prevent it from rolling up properly. If they survive their first year they may live for another 4-5 years. Some individuals have been recorded as reaching 10 years.

Since 2000, hedgehog populations in England have fallen by more than 50% in rural areas, 33% in urban areas (see 'The State of British Hedgehogs 2015' published by the People's Trust for Endangered Species).

Threats to hedgehogs in London Borough of Bromley

In Bromley hedgehogs are now generally rarely recorded, but surveying has highlighted a few areas in the borough where records have been sent from several gardens. These recordings are generally near areas of open space, e.g. in Petts Wood near Crofton Woods and near Betts Park, Penge. All Bromley's records have been submitted to the London Wildlife Trust. Click on London's Hedgehogs to see LWT's map of hedgehog sitings which will include those from Bromley.

Bromley Biodiversity Partnership will continue to ask for records during 2018. Where hedgehogs have been seen, why not get together with your neighbours and follow guidance set out in Hedgehog Street - see Hedgehog Street and click on 'highways for hedgehogs'. There are many other tips for helping hedgehogs on both this site and the British Hedgehog Preservation Society website.

General advice:

1. Hedgehogs travel quite long distances when looking for food, often 2kms or more every night, so make sure walls and fences at site boundaries have safe gaps for hedgehogs to pass through. A gap measuring 13cms x 13cms beneath a fence should be sufficient to enable a hedgehog to pass from one garden to the next.

2. Make sure you have areas within your garden, park, allotment, sports or school grounds that are undisturbed, with long grass and some scrub.

3. Check long grass or scrubby areas for hedgehogs before cutting or strimming.

4. Don't clear away all the dead leaves in autumn, leave some in a sheltered area out of the wind, preferably adjacent to a hedge or scrub where a hedgehog could hibernate undisturbed.

5. If you have a bonfire, check any pile of trash etc. before burning it.

6. Hedgehogs die in steep sided ponds because they can't get out. Make sure ponds have at least one gently sloping bank that a hedgehog can use to climb out. If the pond has steep concrete or plastic sides, add stones and/or water plants (preferably native) along one side to make a gradual slope.

7. Consider planting a hedge of native species. This will support the invertebrates hedgehogs need and as the hedge matures, if it is well maintained, with a thick base, it will provide them with a home and a safe place to hibernate.

8. Make sure no pesticides or slug pellets are used near any scrub, wild areas or hedgerows left for hedgehogs.

9. Hedgehogs quite often become entangled with wire or plastic netting leading to severe cutting of their legs as they struggle to break free, so please ensure any wire or plastic netting is at a safe height for hedgehogs (30cms above soil level) or stored away when not in use.

10. Consider making a hibernation box for hedgehogs. Place in a suitable place beneath logs and/or dead leaves for extra safety and insulation.

11. If hedgehogs visit your garden provide them with some water to drink and maybe dog or cat food, but do not give them bread or milk because they cannot digest them.

12. For further information on how to help hedgehogs visit the British Hedgehog Preservation Society website

13. Please continue sending records to bromleybiodiversity@gmail.com or sue.holland@idverde.co.uk.

If you see a sick hedgehog (including one out during the day) please contact Mavis Righini at Prickles Hedgehog Haven on 0208 462 1168.

This article is copyright © Judith John 2018. The photographs are copyright © Bill Welch 2012 and © Judith John 2018.