Guest post: The usual advice when dealing with wildlife is leave well alone. In the case of hedgehogs, however, and especially at this time of the year, rules are there to be broken, and here's why, says Pauhla Whitaker from the Help A Hedgehog Hospital in Gloucestershire.

If we don't help our hedgehogs, they could be gone by 2020 © Julien Crowther

This is the time we start to see autumn juveniles out and about. These are young hedgehogs from the second litter of the season and if they are small then they are in real trouble. Annie Parfitt, manager at our hospital, recommends that hedgehogs should weight at least 600g or more in order to survive hibernation. Any lighter than that and they will not have the fat reserves to get them through winter and death is a certainty. The tragedy is we are seeing more and more underweight hogs later in the season.

So why is this? Well, with nature, there are always many factors at play but our changing and unpredictable weather seems to be the biggest culprit. Imagine a cold, hard winter with prolonged frost and long periods of snow cover, followed by a dry but not particularly warm spring. Sounds familiar doesn't it? If you believe the weather predictions, this winter is going to bring more of the same.

This spring, hedgehogs that made it through hibernation woke up as the days warmed up and lengthened, only to find there was little spring rain in many parts of the country. As a consequence, the bugs, beetles, worms and other invertebrates they rely on for food were in short supply. This meant that their the breeding season was delayed and although the first litters of hoglets will have survived, the second litters were born very late.

Hedgehogs need to weigh at least 600g to survive hibernation © Damon Cannard

We had another dry spell in many areas in late summer and food was in short supply again, so these vulnerable babies will have been struggling not only to find enough food, but to eat enough of it in time to get up to hibernation weight before the cold weather set in again. The situation was bleak. Judging by the numbers of juveniles we are already seeing admitted to our hospital alone, the doom-laden predictions were spot on.

Already, you can see how easy it is for hedgehog numbers to be drastically affected by one bad season but the knock-on effects will spill over to next year. This is because hedgehogs are not sexually mature until a year of age so if they were born later in the spring than normal, they may not breed at all in their first year and if they do, their own first litters may also be late-born and consequently not survive the winter.

Add to that habitat pressure from urban in-fill, increased traffic and new roads carving up traditional hedgehog routes plus many, many other factors and you can see how precarious a balance it is.

Hedgehogs are nocturnal nomads, travelling between one and two miles a night to forage for food. They are not easy to count but the best estimates we have say that numbers have declined from over 30 million in the 1950s to around 1.5 million now. They are now listed as an endangered species. If the decline continues, we will lose our last hedgehog by 2020.

But don't despair. Here's what you can do to help:

Any hedgehog out at night and weighing less than 650g will not survive winter. Pick it up, weigh it and call your local rescue (see later for details). Looks can be deceptive. Remember that only one of the eight similar sized hogs we brought to Autumnwatch Unsprung was big enough to survive the winter.

Any hedgehog seen out by day is in trouble and is often suffering from hypothermia, even on a warm day so they need to be warmed up. Pick it up and call your local hedgehog rescue for advice. In the meantime, put the hog on a warm (but not scalding hot) hot-water bottle wrapped in a towel and place it gently in a box. Your kerbside recycling box is fine is you don't have a cardboard box. Cover the box with a towel or blanket and place it somewhere dark and quiet.

Tinned cat or dog food is good for hogs © Julien Crowther If you have hogs in your garden, buy a feeding station or make one by putting a paving slab on top of some bricks and put out food. Dry, good quality cat biscuits are ideal as they don't freeze or go off but tinned cat or dog food is good if you put it down fresh each night. Dried mealworms are packed with protein and energy and hogs love them. Hedgehogs are lactose intolerant and must never be given cows' milk or milk products. It can cause severe digestive upset and kill them. If you want to give them a drink, make it water.

Always keep a supply of clean, fresh water available in a shallow, heavy based bowl. If you have a pond, hang some netting over the side and secure it so wildlife can use it to climb out if they fall in. Hedgehogs are excellent swimmers but will die of exhaustion quickly if a pond has steep sides that they can't climb up.

Leave a small area of garden as natural as you can. Log piles, hedges, long grass, piles of dead leaves and shrubs with branches that reach the ground are all ideal places for hogs to make their nests.

Bonfires are death traps for hedgehogs. If you have a fire, stack the material in one place and then move it to make the fire on a different site the day you intend to light it. Even if you only made it the day before, a hedgehog could have moved in overnight to sleep there and will be burned to death. Only last week we had a report of a female with five babies who were only saved because the garden owner though to check their bonfire before lighting it.

Never be afraid to pick up a hedgehog if you think it may need help. They are very docile creatures and deal with being handled very well. Wear garden gloves to protect your hands from the prickles or wrap a towel over the hedgehog to pick it up. At worst, you may find it is a healthy weight and can be released and all you have done is wasted a few minutes of its day. At best, you may find it is severely underweight and needs to go to a carer to over winter and you will have saved its life.

In our small way we have helped to ensure their survival © Damon Cannard

We over-wintered 84 autumn juveniles last winter and virtually all of them survived to be released this spring. We always release in pairs or trios of one male and two females and never release littermates together to ensure genetic diversity and reduce the chances of in breeding where populations may be small.

We've had reports from the public of released hedgehogs taking up residence in their gardens and going on to successfully raise a litter. To know that in our small way we have helped to ensure the survival of another generation of this ancient and endangered animal is a feeling beyond description.

Find out more:

The British Hedgehog Preservation Society is a membership organisation open to all. It has a list of carers on their website and vital information on what to do if you find a hog in trouble. If all else fails, local vets will usually take in wildlife and pass it on to a local rescue for you.

Hedgehog feeding stations are available from many outlets in all sorts of designs. A search engine will bring up hundreds of suppliers.

Hedgehog Street is a campaign run by BHPS and the People's Trust for Endangered Species is a fantastic way to get everyone in your street or village involved in hedgehog conservation. There is loads of information on the website where you can also sign up for a free information pack.

Our own website with more information on the work we do for Gloucestershire's hedgehogs, fundraising events, our "Friends" scheme for supporters and lots of useful hedgehoggy info. Help A Hedgehog is run by a fantastic team of nine dedicated carers. We are always happy to hear from you via the Contact Us form.

If you live in Gloucestershire, whether you've got hedgehogs or not the University of Gloucestershire would like help with their hedgehog survey.

Help A Hedgehog Hospital is on Facebook and we have over 1,200 friends. Come and join us.