Posted by 
Hedgehogs are the most rescued wild animal in the UK. Here’s our guide to help you know when they need to be rescued – and when it is best to leave them alone.
As the nights draw in our spiky friends are commonly seen snuffling around gardens at dusk. In the past, the public was advised to pick up underweight hedgehogs in autumn and keep them inside until spring, as it was thought that they couldn’t survive hibernation.
Ecologists now know that smaller hedgehogs can survive the winter. In fact, with climate change making UK winters warmer and wetter and temperatures remaining higher throughout autumn, hedgehogs are remaining active for longer. This means that some are not hibernating until as late as December or January, which gives them plenty of time to gain weight.
There are over 300 hedgehog rescues in the UK, but in autumn and winter, many of them are full and unable to take admissions. One study in 2006 estimated that there were 40,000 hedgehogs in rehabilitation in the UK alone.
Small but healthy hedgehogs can take time to get up to a healthy release weight. These autumn juveniles can “bed-block” by taking up space that could be used to treat an unhealthy or injured hog.
When a rescue isn’t necessary
Once a hedgehog has been admitted to a rescue it can only be released when it has the same chances as a healthy adult wild hedgehog. A 2019 study by Nottingham Trent University showed that rehabilitated hedgehogs released at 600g over the winter months can meet this criteria. The study ensured that temperatures were above freezing when it released them, but otherwise did not provide any extra support for the hedgehogs.
This means that keeping hedgehogs in rescues until the spring is no longer necessary. Great news for hedgehogs, but not everyone is aware.
Some wildlife rescues continue to keep hedgehogs in over winter and release them in spring – anytime from the end of February to May. Hedgehogs emerge from hibernation when temperatures are consistently above 10°C and will start breeding early in the year. Hedgehogs that are indoors over winter miss an important part of the breeding season.
Some hedgehogs may miss out on breeding altogether, reducing the total number of litters, or have hoglets later in the year. The population may lose some of its genetic variety (a bulwark against disease) with fewer breeding hedgehogs.
Keeping animals in captivity can also cause them stress. Wildlife may experience stress as something akin to facing a predator. Long-term stress can reduce reproduction, impair immunity and engender poor health.
Taking a wild animal into captivity should not be done lightly. Capturing animals, handling, transporting and examining them are all things that have been shown to cause stress.
So how do you know when hedgehogs really need your help?
When you should intervene
Hedgehogs are nocturnal, so animals out in the daytime need help in the autumn and winter. In the summer months, pregnant hedgehogs are occasionally seen building nests during the day, but in the autumn and winter, the only hedgehogs active in the day are unwell.
Any injured hedgehog will need rescuing. They may be dragging a leg, bleeding, wobbling or walking in circles. Hedgehogs face a lot of dangers in neighbourhoods, including traffic, grass strimmers, dogs, netting and bonfires.
Body condition is more important than weight alone. The photos below show two hedgehogs of a similar weight. The one on the left is a very healthy hedgehog, whereas the one on the right is starved.
When they are curled up, healthy hedgehogs are round with their weight evenly distributed around their shoulders and hips. Hedgehogs that are pointed at the tail end and have their hips or shoulders protruding are in poor condition and these are the ones most in need of rescue.
Gardens can be a great habitat for hedgehogs. Creating areas that offer wild food – log piles, long grass and compost heaps – will enable them to dig for worms, bugs, beetles and other insects. Don’t bag up leaves either, piles of them can attract insects and make great bedding for hedgehog nests. All wildlife needs fresh water, so make sure to put a shallow bowl out too.
Remember: hedgehogs that are out at night and appear healthy are best left in the wild.
Emily Harper works for Wild Hogs Hedgehog Rescue and is a member of the Green Party.
