Hedgehogs have been around for 15 million years old. They have survived all kinds of environmental changes over the years, including urbanisation. And city hedgehogs seem to be living a good life. In fact, cities tend to have higher hedgehog populations than rural areas. Understanding why this is could help us to protect them in the future.
Researchers at the University of Hamburg have just conducted a study on city hedgehogs to see why they are thriving. They fitted free-ranging hedgehogs with temperature-sensitive transmitters and recorded the data that came flowing in. “These specialised transmitters allowed us to monitor hibernation patterns and nest site use in winter, as well as activity and home range size in summer,” says lead researcher Dr Lisa Warnecke. The study sites included areas with both major, busy roads and small, quiet side streets: all the elements of a typical city design. The researchers also studied hedgehogs being cared for by a local hedgehog sanctuary.
The results showed that urban hedgehogs can be surprisingly flexible. “We found that urban hedgehogs had much smaller nightly ranging areas than their rural counterparts – 5 hectares verses 50 – and that they adjusted their activity to levels of human disturbance,” says Dr Warnecke. The hedgehogs mainly stayed in private gardens during the day but around midnight, when the number of humans and pets in local parks decreased, they came out to forage and look for mates.
While city slicker hedgehogs were thriving compared to rural hedgehogs, they still showed similar hibernation patterns to rural populations. Over the winter, hedgehogs enter a physiological state called torpor, where their metabolic rate and body temperature decrease significantly in order to save energy. “We were surprised to find that city hedgehogs showed hibernation patterns very similar to rural or captive populations in terms of the depth of torpor, the frequency with which they rewarmed and the overall duration of their hibernation. This was despite city hedgehogs often nesting next to busy roads and having potential food sources available throughout winter – such as food scraps or cat food on private terraces.”
This makes it imperative that urban hedgehogs can access gardens or parks with enough ground cover to allow them to be undisturbed for the entire hibernation season. “Gardens and public parks are very important for city hedgehogs,” says Dr Warnecke. “They need gardens with natural vegetation and public parks less immaculately pruned, with plenty of natural, bushy areas.” City dwellers should also take care to avoid disturbing nesting hedgehogs and to keep their gardens free of anything that could do them harm. “Our work with the hedgehog care station showed that the main problems were injuries caused by fences, plant netting or gardening tools, and sickness from ingesting rat poison” says Dr Warnecke.
If you are lucky enough to have a hedgehog move into your garden, here’s how you can ease their way:
-Hedgehogs can eat good quality tinned dog or cat food (except fish) and will need plenty of water. Do not give a hedgehog milk as it can upset their stomachs.
-Leave areas of wilderness where hedgehogs can snuffle for insects. In a quiet area of the garden, you can even make a hedgehog house or leave a stack of logs for them.
-Hedgehogs don’t thrive in captivity. Also they seriously stink. But they will visit your garden and will let you see them.
-A baby hedgehog is called an urchin. If an urchin falls out of the nest (usually a pile of leaves somewhere hidden) it will make a distress sound that resembles a high pitched piping noise. Don’t put it back in the nest by hand: once the adult hedgehog smells you on the urchin, it will abandon it. Instead, cover it back up and leave it alone.
-Don’t use chemicals or slug pellets – they can poison hedgehogs and other animals.
-Don’t light bonfires without checking to see if a hedgehog’s home is underneath. Also, don’t fork over compost heaps in case a hedgehog or another animal has built their home there. Be careful when trimming hedges, hedgehogs and other animals may be resting there during the day.
The hedgehog is a nocturnal creature which means he only comes out at night. If you see one during the day, it probably means it needs help. So ring your local vet or contact us the DSPCA on www.dspca.ie for advice.