It is not just Google that gets asked why hedgehogs have declined. In fact, over the past 10 years I have increasingly been quizzed on “where have all the hedgehogs gone” by the audiences of my lectures around the country.

Initially I wondered whether this was more an indication of the age of the crowd. Many were Women’s Institute groups and often the youngsters were in their 60s. Perhaps this was a nostalgic thing – harking back to a time when food tasted nicer, teenagers were politer, and there were more hedgehogs.

But their anecdotes were spot on. As the survey work of thousands of citizen scientists was pulled together for the 2011 state of Britain’s hedgehogs report, published by the partnership of the British Hedgehog Preservation Society (BHPS) and the People’s Trust for Endangered Species (PTES), the truth took shape.

Back then they were able to say that, conservatively, there had been a 25% decline in the previous 10 years. In the most recent update, in 2015, the more robust figures reveal that there has been a decline in urban hedgehogs of about a third since the turn of the century and by up to three-quarters in the countryside.

These are dramatic and worrying figures. They do not, as some have suggested, mean we are going to see the extinction of the hedgehog in the next 10 years. But they do mean we are going to continue seeing fewer of these wonderfully charismatic animals unless we start to act.

‘Hedgehogs have a much-mocked relationship with cars and roads.’ Photograph: Kirsty Wigglesworth/PA Photos

Before we can act we need to know why the decline is happening. This has been at the heart of the research work commissioned and funded by the PTES and BHPS.

For urban hedgehogs the problems are fairly obvious, but exacerbated by the recently discovered need for them to have a much larger home range that expected. A viable population of hedgehogs requires, in the best possible habitat (imagine a large park with plenty of interconnected gardens surrounding it) at least 90 hectares of unfragmented habitat.

This gets to the heart of the hedgehogs’ problem. Their habitat is fragmented into pieces that are too small to sustain a population. So hedgehogs will still be present, but numbers may be dwindling even as we enjoy their company on a balmy evening.

To deal with this Hedgehog Street was launched. The plan is simple: people love having wildlife in their gardens and thrill at the birds, bees, bats and butterflies that make use of the ecologically sensitive planting – but they forget that not all wildlife has wings. So, we make a hole in the fence (talk to your neighbour first of course) and get them to do the same and on to the next – spreading hedgehog love along the street.

The success has been a delight, 40,000 households are now signed up. And there are bigger projects using the same idea – in Oxford, Stockport, Chester, Solihull and Ipswich. People are reaching out beyond just their streets and into the wider community.

‘Hedgehogs give us all a chance to getting really close, nose-to-nose, with a wild animal.’ Photograph: Richard Bowler/Rex Shutterstock

Fences are not the only obstacles, of course. Hedgehogs have a much-mocked relationship with cars and roads – and it is likely that at least 100,000 are killed each year (probably more than 10% of the population). Keeping hedgehogs off roads is never going to be easy, better that motorists drive at night with a little more care for wildlife.

Our rural hedgehogs have been suffering an even more dramatic population decline and here the reasons become a little contentious. There is no escaping the fact that where there are more badgers there are fewer hedgehogs. But as I have argued before, to blame badgers for this state of affairs is ecologically illiterate.

Badgers and hedgehogs have coexisted in this country since at least the retreat of the last ice sheet some 10,000 years ago. They are species that compete for the same food – macroinvertebrates such as worms. What has changed in recent years is industrial agriculture and its massive impact on the amount of this food in the soil, affecting both hedgehogs and badgers alike. Badgers have the advantage in that they can predate hedgehogs. They also create a climate of fear, in effect fragmenting the landscape for the hedgehogs as effectively as a busy road.

What can we do for rural hedgehogs? Ensure that there is sufficient food and shelter for them. They are not called hedgehogs on a whim, they really do hog the hedges, and these need to be hedges with enough density to allow them to shelter away from badgers. Food will return to the field margins if farmers can be encouraged to not strip-mine the life out of the land.

Hedgehog numbers throughout Britain have declined because of us; because of the way we use and abuse the land. Yet hedgehogs are an important species to us – we regularly vote it as our favourite animal. But I believe their importance runs deeper.

Hedgehogs give us all a chance to getting really close, nose-to-nose, with a wild animal. They have no flight or fight response; they roll into a ball when bothered. So you can wait, quietly, for them to relax. As they do, you get to see their bright beady eyes and just possibly you might open your heart to them a little more. Which is good for all wildlife. Hedgehogs are like a gateway drug for falling in love with the natural world.