Hedgehogs are like garden superheroes, fending off your foes in the night. If you’re trying to grow your own food organically, pests can be a real challenge, but often you’ll find Mother Nature has it all figured out. These prickly folk will eat not only slugs, but also caterpillars and other creepy-crawlies. As an organic gardener, it’s worth getting to know what makes them tick.
A brief history
The survival instincts and physical features of hedgehogs mean they’ve had little reason to evolve. They thus still resemble some of the earliest and most primitive mammals, in terms of their build and their senses. Curiously the hedgehog has no close relations – even other spiny creatures, like the porcupine, echidna or tenrec, have evolved independently. Erinaceous europaeus is native to the UK and mainland Europe, and there are several other species around the world. The hedgehog has been in existence for 15 million years, but some say it’ll be extinct within decades if we’re not careful.
Hedgehogs are nocturnal, basically because the type of organisms they eat are more active at night than in the day – soft invertebrates need to avoid too much sun so they don’t dry out. A hedgehog’s eyesight is not very good, but it can hear well, and has a great sense of smell. It can sense a food source several centimetres underground, and will gladly dig for it (whether or not there’s a precious seedling in the way).
Hedgehogs basically go into hibernation when the energy spent on foraging is greater than the energy they’ll get from the food they can find. They also need to reach a critical weight in order to make it through the winter, which in the UK is around 450g. Younger ones thus stay out much later in the season than mature ones, and again appear earlier in spring. Adult females will also usually stay out longer than males, to replenish stores after raising their young.
Unlike sleep, hibernation is not a physical necessity, it’s simply an efficient use of energy when resources are scarce. So those in captivity, with warmth and food provided, don’t need to hibernate. In the wild, a hedgehog will naturally come out of hibernation a couple of times per season, possibly leaving the nest to forage, or even moving to a different location. But if this natural rhythm is disturbed, or if the temperature is changed artificially, it can be harmful. They need to maintain a fairly constant temperature of around 4°C to stay safely in this state. They know how and where to build a nest in order to achieve this, and the body naturally does the rest.
Most young are born in June-July, but hedgehogs may keep breeding so late in the season the young will have little chance of surviving without intervention. A typical litter is around 4-5, but on average 1 in 5 will not make it out of the nest, and only around half the original litter are likely to survive to adulthood. After 3-4 weeks, the mother will take her brood out foraging for around 10 days, after which the young are completely independent. If they make it through their first winter, hedgehogs generally live around 2-3 years.
Are hedgehogs really getting rarer? Probably, but it’s difficult to measure. High numbers killed on roads, for example, might indicate bigger populations, or might be a symptom of more open farmland, leaving only the dangerous roadsides for them to live and forage in. Many people blame the urban sprawl in many cities for their decline. Indeed modern trends such as smaller and tidier gardens – perhaps with astroturf lawns and surrounded by impermeable fences or walls – are ill-suited to hedgehogs. But actually these little neighbours are quite happy to live alongside us, as long as we bear a few things in mind.
Entrance & exit
Depending on how much food is available in a given area, a hedgehog might travel up to a couple of miles in a night. If food is more abundant, and of a wide enough variety, they’ll forage in a smaller area, but generally one suburban garden is not enough – they’ll need more like five or six. They can dig or climb to some extent, but they’re more likely to visit if it’s easy for them to get in and out. This can be through fence holes or under gates, preferably in more than one place – an entrance and an exit, as it were – so they can pass through on their chosen route.
Hedgehogs can swim pretty well, but they won’t be able to climb out of a pond if it has sheer sides. As they don’t see very well, they might easily fall into water, so it’s important to give water features a shore or a ramp. Modern cattle grids are equipped with escape routes for the same reason. If you have any other places in your garden where they might fall in and not be able to get out, it’s worth considering.
Hedgehogs will literally sleep under a hedge on warmer days, and are likely to change their location from one day to the next. For hibernation their needs are more specific, so they’ll build a nest – or more than one nest – for the purpose. These are around 50cm in diameter, little chambers of compressed leaves, with a tunnel entrance. If you can keep a quiet part of your garden a bit wild – perhaps with some old leaves and bits of wood leaning here and there – they will thank you for it. Ready-made houses are available, but hedgehogs have survived without such luxuries for millennia, and they’re not so fussy.
Hedgehogs are omnivorous and like a varied diet. In the wild, that mostly means insects. They especially love beetles and caterpillars, but also like slugs, worms and smaller bugs. They’re not all that picky though, and will eat pretty much anything edible, happily clearing up whatever’s dropped from bird tables, for example. It’s traditional to put bread and milk out for them, as they obviously enjoy it. Many folk nowadays say it’s not suitable fare, but other than giving them a slightly upset tummy, it does no harm and helps to fatten them up – a bit like a hedgie version of a take-away. Unlike dogs, humans and other animals, they tend not to binge on one thing, even if it’s something they like.
Dog or cat food is more in line with their constitution, or there is special hedgehog food available to buy, such as Spike’s Dinner. We choose not to impose our vegan beliefs on animals (or even unwilling humans for that matter), but if you prefer a plant-based option, they seem to like sunflower seeds. The downside is that dry food may attract rodents. If you keep an eye out for them in the evenings, hedgies can get used to a certain dinner time, and will take food from quite near the house once they’re used to you. Wetter food is less attractive to rats and mice, as it’s harder to take away and store, so the bread and milk, or wetter pet food, can be a better option, if you don’t mind handling the mess.
Hedgehogs will travel not only for food, but also for water. In times of drought this is obviously important, but even when the weather is not especially dry, they won’t necessarily find water that’s accessible. Keep a small dish like a cat or dog bowl topped up, somewhere at ground level, and you’re more likely to attract visitors. This is especially important if you’re providing dry food, as they’ll get more thirsty.
Traffic is probably the best known threat to hedgehogs, as they don’t see very well and tend to wander about quite slowly. As they haven’t evolved to deal with fast-moving machinery, they often fall prey to it. They’re likely to be put off by busy motorways, but on quieter single-lane roads, it’s as well to drive carefully, and keep a close eye out after dark.
Badgers are the only wild creature in the UK strong enough to kill a hedgehog. They also share a similar diet, so compete to some extent with hedgehogs for survival. The UK badger population has increased in recent years, and in areas where numbers are greater, there will be a corresponding low number of hedgehogs.
The use of slug pellets in domestic gardens is a well-known threat. Many believe it’s due to hedgehogs eating slugs that have already been poisoned, but the biggest problem could be that they eat the pellets themselves by mistake. Some say a hedgehog would have to ingest a huge number of affected slugs or pellets for it to be harmful, but the jury is still out. Rat poison is another possible threat, either from bait being eaten directly, or from eating insects that have ingested it.
Disposable tea and coffee cups can be a nuisance, as hedgehogs will go in looking for dregs, and not be able to come out again without getting their spines stuck. The same applies to tin cans, with fatal consequences more likely. Rubber bands discarded by postal workers can also be a menace, as they get caught on spines and potentially wrapped around limbs. They also look like worms to the short-sighted, and can cause internal injuries if eaten by mistake.
Nets used either for sports or for protecting plants, can get tangled in spines or limbs. Make sure they’re either kept well clear of the ground, or that they have a solid border attached to the bottom.
The strimmer is the most dangerous garden tool, frequently causing injury when used on long grass. Check the area thoroughly before starting. The same would apply to any garden tool in an area that might be giving shelter, especially in the hibernating season.
Around Bonfire Night, many hedgehogs will be looking for a place to hibernate, and might find your innocent-looking wood pile cosy… only to discover it’s a fatal inferno. If you’re planning a bonfire, it’s best to store the wood elsewhere, then check for unsuspecting lodgers by moving it piece by piece to the final site on the day.
Ticks & Fleas
You’ll often see a hedgehog scratching, but this is more a nuisance than a threat. They do carry ticks, which can in turn be picked up by other animals. They also have a problem with fleas, but these are a special type only interested in hedgehogs, and won’t be transferred to dogs or cats.
We’re very fortunate to have several hedgehog employees in our garden, helping to keep the pest population in check. It’s hard to say how many – apart from their size, they all look alike – but the most we’ve seen together is 4. It’s quite unusual for that many to share a space, as they’re generally very independent, and not territorial. But where there’s a plentiful source of food or water, they can get a little boisterous, as you’ll see below.
Usually they just bumble around by themselves, very relaxed and patient creatures, seemingly not at all bothered by human co-existence. We’ve often seen them through the window, or come across them outside in the evenings. They’re happy to sit and stare a human in the face, and to come very close to the house. Fortunately their reactions are quick enough to protect themselves from our dog, Lucy, as she finds them a little too fascinating. They simply curl up and wait for as long as it takes for her to tire of them – a matter of seconds – then they go back to their pottering.
The more we get to know them, the more charmed we are, and the more we want to encourage and protect them – not just for selfish vegetable-growing reasons. Most of what we see is from an outdoor wildlife camera, trained on various parts of the garden. (We use a Bushnell Natureview HD). In real life hedgehogs are cuter, with their dark eyes and soft furry noses, but their behaviour at least is clear to see on film. Hedgie-spotting has given us a lot of joy in the last few years, and we miss them when they turn in for the winter. Here are some clips from this year…
We learned most of the facts in this article from Pat Morris, the UK’s leading hedgehog expert. His book – simply called Hedgehogs, in the Natural History Collection – is highly recommended for anyone wanting to support the hedgie community. It covers everything you ever wanted to know about these mysterious foragers, in a scientific but also very readable and humorous way.
Got any tips or questions of your own about hedgehogs in the garden? Leave us a comment below, we’d love to hear from you.