Dinner table drama
Urban foxes are thriving, but is their place at wildlife feeding stations under threat? Dawn Scott, a Springwatch regular, shares the results of her research.
Cover story Who is top dog at the garden food bowl?
When we had heavy snow in March I remember lying in bed and thinking I should put some food out for the foxes. The vixens were likely to be pregnant and close to giving birth, and there wouldn’t be much natural food about in the sub-zero temperatures. So I grabbed a handful of dog biscuits and scattered them across the frozen garden before quickly rushing back to my warm duvet. But whenever I provide food for foxes or other wildlife, I am conflicted over whether it’s the best thing to do.
Perhaps like many of you, my approach has been to garden in such a way that my patch supports an abundance of natural foods, rather than to put out supplementary food. Yet we are increasingly encouraged by conservation organisations to do just that, and the variety of commercial products available has grown dramatically. From bird seed and fat balls to hedgehog food, this is a big business.
As a scientist, I want to see the evidence behind the message “feeding wildlife helps”. If feeding is going to benefit my local foxes and various other species, then I want to know what, when and how much to feed in order to have the greatest benefit. At the moment, that information is largely lacking.
Foxes might well just rely on extra food during unfavourable weather, from freezing spells to spring and summer droughts, but it could also lead to longer-term changes in their foraging behaviour, including where they go to find food and what they choose to eat. The food we provide tends to be relatively high-energy and accessible compared to the effort involved in hunting and scavenging, so for foxes supplementary food might make sense as an ‘easy option’.
ON TIME FOR TEA
In a study I have been conducting with a colleague, Bryony Tolhurst, we have indeed seen urban foxes modify their foraging trips to arrive in a garden precisely when food is being put out. The accuracy of their timing can be remarkable; if their human is a few minutes late, they will sit and wait patiently for their nightly dinner. When radiotracking urban foxes, we have found that the gardens they visit most are the ones supplying most food, indicating where they go at night depends on where they are being fed.
We have witnessed similar behaviour in urban badgers. One badger clan we followed started each night by visiting a ‘friendly’ garden to fill up on a whole loaf’s worth of jam sandwiches, before heading off to forage elsewhere. Urban hedgehogs also seem to hang around where they are fed. We radio-tracked a group of hedgehogs and found that the activity of some individuals was clearly centred on one particular back garden that supplied a large bowl of hedgehog food.
All of our studies to date have pointed towards the conclusion that supplementary food is affecting urban mammal behaviour. But is this good news for foxes and other species? Or could there be any downsides?
One potential problem is impacts on wildlife health. Supplementary food, such as raw meat, eggs, fruit, nuts and sunflower and nyjer seeds, can be healthy and valuable. Sometimes, though, it is less nutritious than the natural food it replaces, so might have an effect on body fat, teeth condition and immune responses. It also encourages animals to gather in the same place, increasing the risk of disease transmission. For example, the disease trichomonosis seems to have contributed to the recent steep decline of greenfinch populations in Britain (it was first noticed in the species in 2006), and transmission at bird feeders could be a key factor.
As we have seen with our radio-tracked foxes, clumped food may also dissuade wildlife from moving very far from the ‘honeypot’. This in turn could affect social interactions and dispersal, potentially leading to higher local population densities and less movement during the breeding season. Higher levels of inbreeding have been found in waterfowl supplied with extra food; might the same also be true of urban foxes? We don’t yet know.
Anyone lucky enough to have multiple foxes visiting their garden may have witnessed a range of aggressive, threatening or submissive behaviour as they feed. Competition over food also leads to interactions between foxes and other species – especially badgers and hedgehogs. This trio have particularly interesting relationships. For a start, they eat similar foods, forming what is called an ‘interspecific guild’. But more than that, foxes and badgers are both known on occasion to eat their spiky competitors.
We have recorded plenty of examples of competition between foxes and badgers at feeding sites. In one case, we saw a fox carefully approach a feeding badger, nip its backside and then quickly run off, seemingly frustrated with Brock at not being able to access the food. But we have also seen peaceful co-existence. Foxes and hedgehogs may feed from the same bowl, apparently unfazed by each other’s presence.
Our camera-trap studies in gardens have also demonstrated that offering extra food does not just attract wildlife. In one garden, we recorded around 20 domestic cats visiting a feeding bowl during a single night. Clearly, feeding can bring pets and wildlife together in a competitive environment, so your moggie is part of the equation too.
IF THEIR HUMAN IS A FEW MINUTES LATE, THE FOXES WILL SIT AND WAIT PATIENTLY FOR THEIR NIGHTLY DINNER.
What then tips the balance? When do competitors become predator and prey? Is it when the food bowl runs out? Are there seasonal variations? These are questions we are still busy answering. But how much food people supply, where they put it and how frequently could well be what affects the level of competition, since gardens with more abundant and reliable food are likely to attract more diners.
So who are the winners and losers? To find out if foxes might be Britain’s top dogs, we needed to ask the public for help. Our idea was to crowdsource cameratrap footage from anyone who had recorded animal interactions in their garden, together with information about how they provide food (if they do). Behind the scenes, we trained a group of university students and IT support staff working 24/7 to download and analyse the behaviour in the videos sent in. The ‘Springtails’ project launched on Springwatch on BBC Two in 2017.
First, we assessed the types of interactions – whether they were agonistic (competitive) or neutral, and whether there was any other behaviour, such as investigation or play. We also looked at what are known as dyadic encounters, where two individuals contest a resource; in these cases, we recorded who came out the ‘winner’ and ended up with ownership of the dinner plate.
In all, 73 per cent of the Springtails contributors fed wildlife in their garden every day, offering more than two handfuls of food. Of the people who provided food, 76 per cent said they did so in the same place in the garden, while 16 per cent said they scattered it. This suggests that
supplementary food is both abundant and reliable. However, we were to find out that it is not always the healthiest.
Most Springtails respondents fed their foxes and other urban mammals pet food, peanuts, mealworms or commercial hedgehog food. But nearly 10 per cent said that they provided carbohydrate-based food, such as bread, pizza, pasta, cakes, biscuits, crisps and breakfast cereal. These items are not very nutritious and are high in sugars and fats, which could result in animals filling up on non-natural food; the impact on wildlife health remains unknown.
Badgers, not foxes, appeared to be top dog in gardens. They won the competition for food with foxes and cats. In fact, foxes fared the worst, losing to both badgers and cats, with the latter frequently scaring them off and winning nearly twice as many stand-offs. The size difference is not as great as you might imagine: a big, well-fed pet cat weighs much the same as a small fox.
Foxes got on better with hedgehogs, with less visible competition. Nonetheless, 41 per cent of all fox-hedgehog encounters were still agonistic, with foxes winning half of them. We observed no evidence of foxes killing hedgehogs. But in a small number of badger–hedgehog interactions, we did see the competition switch to predation. This reinforced the theory that attracting hedgehogs and badgers together with food might sometimes lead to unwanted predation. Cats were submissive in encounters with hedgehogs, and tended to avoid or run away from them.
We noted little aggression between badgers, possibly because they already have an established social hierarchy, but saw quite a lot of aggression ress ion between foxes, representing 35 per centc of all fox–fox interactions. Most surprising was the level of aggression between hedgehogs, accounting for 52 per cent of their innteractions. One behaviour I called the ‘barge annd roll’ involved a hedgehog running at anoother one with its head down, making its rivall roll into a ball. The aggressor would then rolll the other hedgehog away, sometimes accross a garden and even in one case down a flight of garden stairs! Evidently, hedgehogs do not like sharing their food bowl.
The Springtails study suggests thhat supplementary feeding in gardens does indeed bring more animals together in closer proximity, leadinng to competition. Also striking is the fact that when food was scattered oor left in multiple places, there was leess aggression, as animals could eat inn
Below: a vixen feeds from a bird table in a Bristol garden. In Britain, foxes first became established in cities during the 1940s. FOXES FARED THE WORST, LOSING TO BOTH BADGERS AND CATS, WITH THE LATTER FREQUENTLY SCARING THEM OFF.
their ‘own space’. Clearly, we need more research into the effects of feeding wildlife, and I’d also argue that the public need more practical advice on how to go about it.
Gardens make up one of the UK’s largest spaces for wildlife – it’s an oft-repeated fact that they cover a bigger area than all of the national nature reserves put together. But I wonder if, in the long term, creating diverse habitats in our gardens that supply plenty of natural food and refuges may be preferable to supplementary feeding. On the other hand, there are certain cases – take Britain’s goldfinches and overwintering blackcaps, for example – where there appear to be strong links between increasing numbers and garden feeding.
We also mustn’t forget that feeding foxes and other wildlife gives enormous pleasure to millions of us. And I hope that the few dog biscuits I left out for one of my neighbourhood’s pregnant vixens on that bitterly cold night might have helped her just a little bit. If I see any local cubs this spring, I’ll wonder what difference I might have made.
WE NEED MORE RESEARCH INTO THE EFFECTS OF FEEDING WILDLIFE… AND THE PUBLIC NEEDS MORE PRACTICAL ADVICE.
Above: food in gardens creates competition between badgers and foxes ( above); hedgehogs and foxes ( below) and domestic cats and foxes ( right). The moggie has the upper hand in this London graveyard.
Fleet the fox was named by University of Brighton researchers and fifitted with a radio-collar. He walked 315km into the Sussex countryside to find space to form his own territory.
Urban foxes adapt their foraging trips to arrive in gardens when food is being put out by householders. They will also scavenge from bird tables, dustbins and compost heaps.
A fox steps into a greenhouse. In an urban environment its territory can be as small as 0.2km2. Below: camera-traps provide valuable data on foxes.