Help the hedgehogs: what gardeners can do to protect them
They are among our most popular garden visitors - yet the hedgehog population is estimated to have halved in less than 20 years.
Climate change has brought about long, hot summers, which can pose a threat to these prickly mammals.
Here's how hedgehogs are affected - and what you can do to help...
"Hedgehogs largely eat invertebrates - among their favourites are worms and beetles," explains conservation research scientist Dr Tom Moorhouse.
"In long, hot summers when it's dry, the invertebrates tend not to be near the surface, so the amount of worms available in both gardens and agricultural areas massively declines. Hedgehogs and insectivorous birds start running out of food."
Hedgehogs who live in agricultural areas might face problems from badgers, Moorhouse warns.
"Badgers are super-specialist in eating worms. When it's hot and dry, they can't dig up worms either. They are not only competing for the same food that the hedgehogs want, they are also big and strong enough to eat hedgehogs."
He continues: "In long, hot summers, the predators that hedgehogs have are more likely to be desperate enough to take them on. That counts for foxes as well. Even if they don't manage to get hold of a hedgehog, the hedgehogs are going to be forced to flee more often, using up more energy and [making them] unable to forage as much."
Moorhouse, whose new book Ghosts In The Hedgerow goes some way to explaining their plight, says gardeners can do a lot in spring - when these mammals come out of hibernation - to give them a head start on the warm weather ahead.
"They will be looking for as much food as they can get their paws on, such as worms and beetles, slugs and snails. Worms are a major part of their diet."
Pests and diseases
When hedgehogs are in a weakened state, they become more susceptible to pests and diseases, warns Fay Vass, chief executive of charity The British Hedgehog Preservation Society.
"Parasites thrive on creatures which aren't doing so well," she notes. Parasitic worms called lungworm can invade the lungs and can be fatal. Slugs, which form part of the hedgehog's diet, are carriers of lungworm and when the hedgehog's immunity is low, lungworm can take hold.
"Hedgehogs also pick up tics naturally, wandering in long grasses. Usually they will drop off, but if the hedgehog is weak it will attract a lot of tics which will feed off it," she adds.
What you can do to help
How to tell if a hedgehog is sick
"That's tricky. We don't want to encourage people to pick up hedgehogs, but you can generally tell if a hedgehog's underweight because rather than being in a round ball, it looks almost diamond-shaped," says Moorhouse.
Food and water are key
"Leave out food, leave out water and leave it be, unless it's clearly at death's door. You can buy bespoke hedgehog food from supermarket, or any good quality cat food or dog food will do the job," advises Moorhouse.
Vass urges gardeners to give hedgehogs the best start as they come out of hibernation by putting out food and water to help build up their fat reserves, which will give them a better chance of surviving any period of famine.
"If we have another scorching summer, they will be very thirsty and you have to think, where are they going to get water from?" asks Moorhouse.
"If they're in urban areas it's basically garden ponds, and if there aren't any of those around, they are in trouble. So leave out a dog bowl of water and check regularly to make sure it's being drained."
Help give them shelter
"Leave an area scruffy because that will be filled with all the invertebrates they're going to eat - and they can also hide in it," Moorhouse advises.
Vass says leaving log piles in the garden will give hedgehogs natural shelter and food, as invertebrates may also inhabit the space.
"Hedgehogs are ending up much more of an urban species than they ever were," Moorhouse explains. "They seem to be declining slower in urban areas than in rural areas, but they are still declining in urban areas due to urban intensification - so every time you put in a new fence, or a new house is built on what was scrubland, or you strim down weeds or put in decking, it crowds out space for nature.
"Make sure they can get into your garden. You may have the best garden on the planet for a hedgehog, but if they can't get into it, it's not worth anything. Talk to your neighbours, ask if they'd mind if you cut a CD case-sized hole in your fence, and you're opening up the garden for hedgehogs."
Ghosts In The Hedgerow: A Hedgehog Whodunnit by Tom Moorhouse is published by Doubleday, priced £16.99. Available now.