Hedgehogs face a prickly future in Ireland

Over the next few weeks, hedgehogs will be awakening from their winter slumbers. The prickly porkers have slept, tucked up in nests of leaves and grass, since October or November, relying on their heating fuel, brown body-fat, for sustenance, writes Richard Collins

During hibernation, their heartbeats fall to a fifth of the normal rate and their body temperature can drop to 4°C. Nor will all of the sleepers survive. ‘Pups’ born late in the season are particularly vulnerable; laying on enough fat, before taking to their beds, is particularly challenging for them. Much depends on the severity of the winter.

‘Gráinneóg’, the ‘ugly one’ with up to 7,000 spines, has short legs small eyes and a keen sense of smell. Not the brightest star in the animal firmament, its brain is small. This most ancient of our mammals, and its relative the pigmy shrew, have changed little in 15 million years. So how are hedgehogs coping with today’s fast-changing world?

Getting a handle on numbers is difficult. Red List No. 3 (Terrestrial Mammals), published by the Wildlife Service, says that “there is no population estimate available for Ireland”. Our neighbouring island, however, has the resources and man-power to monitor its wildlife populations more closely. The British Hedgehog Preservation Society thinks that there are about 1.5 million hedgehogs there. This suggests that we have, perhaps, around half a million here.

Our Red List states that there is “no evidence of a population decline” in Ireland. However, alarm-bells have been sounding in Britain for over a decade. By 2007, clear evidence had emerged that hedgehogs were in trouble. The numbers recorded during the Hedgehog Road-kill survey, that year, were down by at least a third on the 2002 figure. Data gathered during the Breeding Bird and Living with Mammals surveys confirmed the decline.

The 2018 report of the British Hedgehog Preservation Society and the People’s Trust for Endangered Species has appeared. It says numbers are falling in the countryside; the species is almost completely absent from some arable areas. Most hedgehogs now live in, or around, towns and villages.

The reasons for the decline are fairly obvious. The removal of hedges and copses, when larger fields are being created, reduces the habitat available. Intensive farming results in hedgehog food shortages. Insect larvae are an important food source. According to a German study, insect numbers there have fallen by about 75% during the last two decades.

Vehicles take an ever-increasing toll; trying to cross roads at night a hog, dazzled by headlights, rolls into a ball, with fatal results. The defensive strategy, which served these animals well for millions of years, has become a liability. Males are especially vulnerable during the breeding season, as they travel widely in search of females. Water tanks, too, can be lethal. Entering a tank to drink, a hedgehog may be unable to climb back out. Cattle-grids are also death-traps. Animals falling between the bars, while searching for food, become incarcerated.

But not all the news from Britain is bad. According to the current report, the outlook for hedgehogs is brighter in cities and towns. Although fewer seem to be present than there were 15 years ago, there is evidence of an increase in urban numbers over ‘the last few years’. Many still die from eating the victims of slug pellets put out by gardeners, and numbers in built-up locations were down year on year between 2004 to 2012, the decline appears to have levelled off. Things may be looking up.

• Emily Wilson & David Wembridge. The State of Britain’s Hedgehogs 2018. British Hedgehog Preservation Society.