Fox Facts
Breeding: Rutting season starts in December, reaches its peak at the end of January/February, when much daytime activity becomes common and when several foxes can be seen playing and interacting on frosty mornings or in snow. Mating is often seen during the day and night at this time. Foxes also become quite bold and oblivious to their surroundings and the dog will spend most of his time closely following the vixen during the day and night. Much barking is heard during the evenings at this time, probably to maintain contact between individuals.
"The vixens have a single oestrus period lasting three weeks, though fertilisation is only possible during three days, but mating occurs outside this period.' From 'The Handbook of British Mammals' by Corbet & Harris.
Young: On average 4-5 cubs are born, mainly in March. The birth and growth of fox cubs are similar to domestic dog puppies. The cubs are born blind and deaf onto the bare soil down in the earth. They are not hairless but have short black fur. Those that have white tail tags will already be showing them. Eyes open at 2-3 weeks of age when solid food will start to be nibbled. At first the eyes will be a slate blue colour but change to brown or amber at 4-5 weeks. This coincides with changes in fur colour, the chocolate brown starts to change with the patches of red beginning to develop, starting on the face. Some cubs are more red than others at birth and will develop their red coat earlier. Some stay quite dark for life. Individuals from the same litter may also vary greatly in colour.
Cubs first start to appear at the mouth of the earth on very wobbly legs at around 3 - 4 weeks. By 4 - 5 weeks they are trotting around and will know the area around their earth well. They can now forage for the odd beetle, slug or worm.
'From 3 weeks onwards, the vixen spends an increasing amount of time away from the cubs and by 4 -5 weeks often only comes back to feed cubs.' From 'The Handbook of British Mammals' by Corbet & Harris.
Normally by 6 weeks, the whole of the coat is coloured red, but still woolly. The muzzle becomes more elongated, giving the appearance of a miniature adult.
Adult guard hairs appear at 8 weeks old. From 4 weeks onwards cubs can bark like adults, but in a higher pitched tone. They usually bark when the parents spend long periods of time away from the cubs. Ground around the earth is usually scattered with debris such as bones, fur and feathers. Small cub scats accumulate around the earth entrances and the surrounding ground. Rabbit and hare bones may be found completely devoured of flesh, the young cubs suck all the meat off as their jaws are not strong enough to crunch the bone yet. Cubs can be seen playing at almost any time of the day at this stage, but from 6 weeks onwards they gradually become less diurnal and more nocturnal and crepuscular - active throughout the night, dawn and dusk. Areas of long grass and vegetation become flattened due to cub playing. Although adult visits become less frequent towards the end of May in order that the cubs will be encouraged to explore, adult attention has not declined. The cubs will now lay-up in cover away from the earth and I have watched vixens visit them about 8pm in June and July. They will visit them each evening and surprisingly still suckle the cubs regularly at this stage. Cubs will still beg for food from parents in August, when they are nearly adult size.
Adult Mortality Rate: Mortality varies from season to season. In the peak of courtship (January & February) there will be a higher death rate in both sexes. Although foxes remain largely monogamous, there is a certain amount of promiscuous behaviour during the mating season, mainly in dog foxes. During this time foxes wander into strange territory and are covering much more ground than usual, crossing many more roads than they would normally do and generally exposing themselves to more danger due to their increased activity and travels. The number of adult foxes seen dead along roadsides also increases at this time. When cubs are being weaned onto solid food in April and May the parents have to be twice as active by day as well as night in order to search for the extra food, thereby again exposing themselves to higher levels of danger.
Cub Mortality Rate: Cubs may be killed by foxhunt hounds, dug out by man and his terriers, shot, run over, eaten by badgers, taken by golden eagles in Scotland, killed by other foxes or generally die from disease.
"In Northern Ireland, fox population is probably limited by high cub mortality as a result of various diseases." From The Handbook of British Mammals by Corbet & Harris.
As a general rule, a higher percentage of cubs die than adults, especially in areas of heavy traffic. Dr. David MacDonald - author of 'Running with the Fox' - explains that 63% of Oxford city foxes die before their first birthday, largely due to traffic accidents.
Diet: Foxes will eat just about anything but they do have their preferences. The diet of an individual can vary so much that the fox is considered omnivorous rather than carnivorous. The amount of predation on birds and mammals, whether wild or domestic, varies from habitat to habitat and is a big debate. Fruit can make up a large part of the diet during the Autumn and earth worms are commonly eaten.
Rodents: In Britain the field vole is preferred more than any other rodent. Wood-mice, rats, bank voles and squirrels are seldom taken if field voles are around. In Ireland the next best thing is the wood mouse, followed by bank voles (only found in County Clare). Rats and squirrels come last on the list.
Insectivores: These consist of common shrews, pygmy shrews, water shrews, moles and hedgehogs. Hedgehogs are often eaten if the fox can get to the underparts. Shrews and moles may often be found dead around earths but not eaten, although moles may sometimes be partially eaten. In Ireland the pygmy shrew and hedgehog are the only insectivores to exist.
Rabbits and Hares: Where a good number of rabbits are available to the fox, they will be a major part of the diet. Foxes depend heavily on rabbits in Ireland, although in urban areas they are less likely to be important. My own studies have shown that in rural places where rabbits abound, observations in daylight are more frequent and there is a higher fox population. This could cause fluctuations in local fox numbers from year to year as rabbit numbers rise and fall due to myxomatosis. As field voles are plentiful in Britain the rabbit is not quite so important to the fox. The brown hare of Britain is not commonly found in the diet of the fox, not because they are not a preferred food - for they very much are - but because they are difficult to catch. Although the mountain hare of Ireland and Scotland is a major part of the fox diet this is only at the hares' peak population. Their numbers fluctuate every 10 years.
Lambs: Although dead lambs can sometimes be found around breeding earths, this is no proof that they were actually killed by the fox. Many intense prolonged studies have been made by scientists in Scotland, England and Wales on fox predation of lambs. Some farmers claim to have more losses to foxes than others, none had ever actually seen a fox taking a healthy lamb and there is still little evidence of fox predation on healthy lambs. This is not to say that attacks never happen but when they do they must be so few that the Ministry of Agriculture in Britain refuse to list the fox as a major pest for annual lamb mortality.
In remote areas of Scotland, scientists have discovered that sheep may be an important part of fox diet without having any effect whatsoever on the survival of sheep. Predation on lambs occurs more in very remote areas with poor land and where natural prey may be harder to come by. For instance, when vole and rabbit numbers drastically fall, foxes may rely more on sheep carrion or lamb. This indicates that sheep meat is not a preferred food and foxes would rather avoid lamb and mutton when other food is available.
'Lamb survival on the Scottish isle of Mull, where there are no foxes, was no better than on the nearby mainland, where foxes occur and were hunted.' From 'Running with the Fox' by David MacDonald.
Poultry: Foxes kill when they need to. If there is an opportunity to scavenge, they would rather that than to spend all their time hunting. Nevertheless, it would be wrong to say that they are not sometimes a nuisance to people.
Although chickens and ducks are sometimes taken, it occurs less commonly than thought and happens more on remote farms. There may be the odd "nuisance" fox in certain areas which makes a regular habit of attacking poultry but the culprit, of course, is invariably destroyed. Instead of this it would be far more effective for the poultry owners to shut up birds securely at night. Shooting the fox may solve the problem for a while but it only makes room for another and sooner or later hens will go missing again. Intense fox control might stop it for good, but will be more costly in the long run than building one secure hen-house.
Birds: Blackbirds are sometimes caught as they often run along hedgerows for quite a while before flying off, thus quite often being directly in the fox's path. Birds' eggs are taken but again only when the fox comes across them. Large numbers of gulls and terns along sea cliffs can be killed but this happens due to there being such an unnatural balance available to the fox. When this occurs, a predator will surplus kill in order to bring the number down to natural balance and each bird shall be taken off, buried and stored for when food is hard to come by. The same thing happens in a chicken run, the fox will come back for each one to take away and cache - if he is left undisturbed. Likewise foxes can cause havoc in a game-keepers' pheasant rearing pen - again an unnatural amount of birds together triggering off the surplus killing. All predators do this, unknowingly of course, by instinct.
'In one breeding season about 200 black-headed gulls were killed by each of four foxes, with 230 killed in one night.' From The Handbook of British Mammals by Corbet & Harris.
Birds like pheasants and partridges are not often in the staple diet of the fox for in natural conditions the animal would not come across them often enough and they would be harder to catch. Foxes are not usually a threat to pheasant, partridge, grouse or pigeon populations although sometimes they will take brooding partridges and their eggs.
Worms and Insects: When young foxes first start hunting and foraging for themselves, worms and beetles may be the only things found in their stomachs for the first few months of life. As they grow into adulthood they get to know the best worming grounds. Cubs are taught how to pull worms from the ground without breaking them in half by the vixen, who shows them how to keep the worm taut when pulling it and to gently prod it with a paw, consequently loosening it from the ground with small vibrations. The worm's hold gradually weakens and thus no part of it is lost by the fox. The cub learns quickly but - only naturally - fails the first few attempts.
"Earthworms, in some months, could provide over 60 per cent of the calorific intake." From The Handbook of British Mammals by Corbet & Harris.
In late Summer and Autumn, beetle wings are commonly found in scats. If examined closely, much soil and sand can be found together with the cheatea of earthworms. Slugs are eaten quite a lot and the odd grasshopper.
Fruit: This mainly occurs in fox diets during Autumn, when the whole of the fox dropping may consist of blackberry pips. Windfall apples are also taken but this will vary from place to place. Cooking apples are not favoured. Fruit is quite a popular fox food and plums, grapes and other berries are eaten when available. Vegetable matter is not often taken though grass is frequently found in stomachs and scats. Raisins are a very attractive food if put out for foxes by urban dwellers.
Analysing Scats: The best way to find out the diet of the local fox population is to analyse scats in detail. This can be done by collecting as many scats as possible from the known fox haunts and soaking them overnight in a jar of water.
The next morning, stir vigorously until broken up. When the contents have settled, use a pipette to spread some of the settled sediment onto a microscope slide. A low powered microscope will do.
If the fox has been eating worms you will see the little bristles that grow out of the worms skin, these are called cheatea and help the worm to grip the earth when being pulled out of the ground. Under a microscope they look like little daggers. The rest of the jar's contents can be put through a fine sieve or old stocking. Once drained put them into an enamel dish with clean water so that the remains can be identified clearly.
Animal bones and fur shall be harder to identify than earthworm cheatea, beetle wings and grass. Grass is sometimes consumed by foxes but the explanation for this is uncertain. Suggestions are that it may be for roughage or simply taken by accident when foraging for insects. Although the surprisingly large amounts of grass often found in scats, indicates that it must be taken purposefully.
Rabbit bones are usually split into sharp pieces and the fur of rabbits is easily identified and fairly obvious in scats. It is not so with bones and fur of rodents. Identification of these can be quite difficult, for the acid in the fox's stomach works so brilliantly that it breaks down and dissolves most of the skull and teeth of the rodent, leaving only the bottom jaw visible.
The best time to find out how much foxes predate on rabbits in an area is to wait until the rabbit population is thriving and healthy. The same goes for the Irish Hare, since its populations fluctuate every 10 years. Woodmice and field voles also have an up and down cycle.
A field guide for mammals can be obtained from any good bookshop to help identify bones and fur of particular rodents or birds. Books on analysing owl pellets are very useful in learning how to identify bones, fur and feather.
Fruit is not hard to identify. Some scats can solely be made up of a solid mass of blackberry pips and if the fox has been eating only blackberries the scats will be a runny blackberry looking mass - rather like a small cow-pat. If plums have been eaten, the stone will be found in the scats.
Another advantage of analysing scats is that they can help you to determine the size of the fox's territory. This is done by regularly leaving out food and scattering small bits of brightly coloured wool throughout it. Hopefully then this will be consumed by the fox and eventually show up in the fox's dropping. When scats with wool are found this will give you an indication of how far the fox is travelling around from where it is being fed.
