Another Life: Hedgehog study to shed light on threatened reclusive species

In the days when we had ducks and a fowl-house beside the stream, it was sometimes hard to round them up and get them all to bed. One went missing three nights in a row, but turned up each morning to be fed .

She had nested and laid seven eggs in a thicket of briars and meadowsweet, a natural if hazardous thing to do. An anguished quacking in the hollow at midnight found her running up and down beside the fowl-house, begging to be let in.

My flashlight spotlit the nest and the intruder: a hedgehog munching on an egg. Extracted through the briars with our long fire tongs, he spent the night in a nursery coop from which, in the morning, he’d escaped.

Even signs of hedgehogs came to dwindle after that: no more coughs and snuffles from the hedge-bottom or curls of black droppings in the grass. A neighbour brought us a hedgehog that had been annoying a great Dane by trying to lick his dish clean every night. It disappeared into our fuchsia thickets and became, we assumed, yet another hedgehog casualty, savaged by the badger from a willow thicket over the fence.

Council to trial tech to identify dead animals and notify owners

---

Ireland needs water charges to meet environmental targets, OECD warns

---

Legislators must act urgently to stem biodiversity loss, committee told

---

Erinaceus europaeus was an introduction to Ireland, probably for food, and first recorded in Waterford in the 13th century. A limited genetic strain suggests descent from a few animals brought in by a Norman settler. Seven centuries later, there’s very little known about its current status in Ireland.

It’s in decline across Europe and a threatened, red list animal in the UK. Ireland shares much of the urban sprawl and increased road traffic that reduce its numbers.

Just how the animal is faring may soon emerge as volunteer citizen scientists enlist for Ireland’s second nationwide hedgehog survey.

The first survey, launched last summer by researchers from NUI Galway and the National Biodiversity Data Centre, brought more than 2,000 hedgehog sightings from all over Ireland, with many people reporting hedgehogs visiting their gardens through the summer.

The project forms part of the research of PhD student Elaine O’Riordan at NUIG and its second phase will tell more about the habitats the animals most favour.

From this month until September, volunteers will place 10 plastic footprint tunnels within a one-kilometre square for five nights, and then check them for the distinctive five-toed tracks of hedgehogs. Locations of training workshops are now available online at irishhedgehogsurvey.com and local authorities and NGOs across Ireland will help in the live training of volunteer teams.

The current knowledge of hedgehog habitats here owes much to the work of Dr Amy Haigh as a PhD student in UCC in 2014. This first deep study of the European hedgehog in rural Ireland ranged from genetics and habitat choice, through sex and family life to its maximum running speed (30-40m per minute) and road mortality.

Pastoral farmland

Dr Haigh had first to find and radio-tag her rural hedgehogs. This ran into problems that yielded a spin-off paper for the Journal of Negative Results. Failing to find enough hedgehogs with infra-red cameras, rabbit traps or footprint boards, she took to searches after dusk, four nights a week, with a 2 million candlepower spotlight.

The males among the 24 animals she radio-tagged travelled surprisingly widely over the Cork countryside – across some 54 hectares – and their roaming for casual sex in spring led to peak deaths on the roads.

The hedgehogs’ choice of habitat at various times was distinctive, though Cork’s mosaic of arable and pastoral farmland is far from typical of the whole island. In autumn, they were found right out to the middle of the region’s big stubble-fields, then teeming with slugs and beetles.

When food was so plentiful, both badgers and hedgehogs, often predators and prey elsewhere, could co-exist, both eating much the same things. But badgers remain “predators and interest continues in their impact on hedgehogs in the countryside”.

A recent international study focused on experience in the UK, where, in areas culled of badgers for TB eradication, hedgehogs more than doubled in five years. The badger population is, however, rising too, with an 88 per cent increase across England and Wales in some 25 years, and the study concludes that "the balance of co-existence between badgers and hedgehogs may, therefore, have been tipped" (doi.org/10.3390/ani9100759).

In this study’s maps of badger and hedgehog sightings, the latter look more abundant on the arable land of eastern England, while badgers prefer the woodland of the south and west.

Ireland’s area badger culls for TB control have, in the past, been even more intensive and sustained than those in the UK. That, very probably, has helped the local hedgehogs. In the new move to badger vaccination, however, “the objective will be to grow new badger populations”. This could restore or increase their national numbers.

The new hedgehog surveys should provide some baseline data from which the ongoing “balance” of the species can be judged.