Tips and Advice

Wilhelma is often posed questions about local wild or domestic animals. Our tips on the most frequent questions are to be found here:

Hedgehogs in winter

When the outside temperatures often sink to below 15°C in autumn, the hedgehog will look for winter quarters under mounds of leaves, twigs or debris. In order to survive hibernation, a hedgehog needs a minimum weight of 250g. People often collect hedgehogs in the autumn, thinking that they must look after them indoors during the winter. This well-meant love of animals can, however, do more harm than good to a healthy hedgehog. Studies carried out by the Biological Society for Wild Animals, Munich, show that of those animals that were looked after by humans during the winter, only 30% were still alive the following autumn. After the following winter the amount was even only 10%. There are various reasons for this:

  • The wrong food (milk, raw eggs, fruit) can cause chronic diarrhoea and even incurable kidney and liver disease
  • Treatment against worms, often carried out before hibernation, means that the animals have more problems with re-infection when they are let free in spring
  • The animals are subject to additional stress if several hedgehogs are kept together in a limited amount of space
  • The hedgehogs are often let free far too late in the spring. By then most territories have been occupied by other hedgehogs, and the animal will have difficulties finding a suitable territory of its own.

In comparison: depending on how hard the winter is, between 35 and 50 percent of the hedgehogs left outside survive their hibernation.
The hedgehog is not an endangered species, of course, but is protected all year round by German laws on preservation of the species. It is forbidden by law to catch these animals (§ 13 BArtSchV).
Private people are only allowed to keep and look after ill or underweight animals for a restricted length of time (§ 20 BNatSchG). A hedgehog is considered underweight if it weighs less than 250g. Signs of illness are: if the animal cannot roll up properly into a ball, breathes with a rattling noise, has a dry nose or behaves listlessly. Such animals must be treated by a veterinary doctor. But in general the rule is: healthy hedgehogs, including those that weigh only 250g, are better off left outside and not taken indoors.


Stone martens in the attic

If there are rumbling noises coming from your attic, it might not necessarily be a stone marten! Dormice also like to spend their time in attics. In order to find out who your lodger is, you can leave out a raw egg. If it has vanished the following day, then it is definitely a stone marten. Should you find signs of gnawing and small pieces of wood on the floor, then your guest is probably a dormouse.

There are two species of martens living in Europe that are very similar to each other – the stone marten and the pine marten. Whereas the pine marten avoids any proximity to humans and lives only in woods with old trees in them, the stone marten has taken over the town as a habitat, often making itself unpopular as a lodger in the attic or by biting car cables.
If you feel molested by the presence of a marten, you should find out where it manages to get into your attic. When you are sure that it is not at home, in the late evening for instance, you should block up this entrance. The marten will then find a different place to sleep. You will need patience, though, as the marten will try to remove the obstacle or find another way in. And be careful – make sure that there are no little martens in the attic!

The stone marten is subject to hunting laws, i.e. only people with special training (e.g. a hunting permit with a special training in trapping) are allowed to catch these animals in a box trap, and then only from mid October to the end of February.


Stone martens in a car

Stone martens are solitary animals, are nocturnal and have territories, i.e. every marten lives in one area all its life, and defends this from other martens. The males in particular also mark their territories optically, by leaving scratch and bite marks in suitable places, so that others know that this territory is already occupied. They leave their marks particularly intensively near the borders of their territories, so that martens in neighbouring territories know exactly where the borders are. Plastics and rubber materials are especially suitable for leaving bite-marks on.

Your car might just be in a place in a marten's territory that he wants to mark.  As long as your car stands in this spot, it will be used regularly as a marking place. Maybe you are even parking on the borderline between two territories, so both of the rival males will use your car as an absolute duelling place for leaving their marks!

The easiest way of protecting your car from further damage is to park it at least two streets further away from the usual spot. Methods of deterring martens, such as blocks of WC-cleaner, dog hairs or other materials that have a strong smell or taste, or apparatuses that send out ultrasonic sounds, have all proved to be ineffective. Car manufacturers are looking for new methods. Mercedes and Audi have developed a high-voltage device that converts the 12 volts of the battery to the strength of an electric fence. This is not dangerous for man or animal, but weakly electrifies the engine compartment of the car. This weak current is just enough to scare off the animal and is thus an effective deterrent, without harming the animal.


Dormice in the attic

You are most likely to notice the presence of a dormouse during the summer months, as they are only active then. Although these nocturnal animals can be a nuisance, they do not generally cause a lot of damage. Buying a device for emitting high-frequency ultrasonic sounds to drive away the dormice is not necessarily recommendable, as it does not always work all the time. If you want to keep dormice out of your attic, you should find out where they get in. Dormice can only move into an attic if the house is not perfectly sealed, that is if there are holes that are big enough for the animal to squeeze through. If you seal all the gaps, you should be rid of the dormouse problem. But make sure first that there is no dormouse trapped inside, and that there is no nest with young animals. By the way, if you move a nest with young animals to a different place, you are committing a minor infringement of the law. It is also forbidden to hunt, bait, catch or kill dormice (§ 13 and § 14 BArtSchV), as these animals belong to especially protected species according to German laws on the protection of the species.


Bats as lodgers

Because of their usefulness as insect-eaters, bats have been protected by law for more than 50 years. But in spite of this they are becoming rare. Some species are nigh on extinct. Therefore all 37 species of bats living in Central Europe have been included in the "IUCN Red List of Threatened Species".

Bats are most often to be found directly in residential housing. They take up living quarters here in narrow cracks under wall facings, under house eaves, between roof tiles, behind boards, the framework of flat roofs and in similar places. Whether the bats survive or not therefore depends to a large extent on the understanding of the house owner. Any building activities in bats' living quarters should not be undertaken before the beginning of September. It is not until then that the bats leave these places to go into hibernation.

Before starting any building work, you should first make sure that there are no bats still present. The quarters should always remain accessible by leaving a possibility for the bats to fly in and out, for example an opened gable window. Timber preservation treatment is particularly dangerous for bats. If it is absolutely necessary to impregnate the timber, only stuffs that are harmless to bats should be used – sodium borate or impregnating stuffs containing pyrethroids. But these stuffs should also only be used in attics when the bats have left from September onwards, and before February.
Bats spend the winter months (September to February) in hibernation. Most species retire to frost free and draught free vault-like constructions with a high relative humidity, like hollow tree-trunks, tunnels or mines or beer cellars. During the hibernation period bats should not be woken up by any disturbance. If they do wake up, they use a great deal of energy and their fat reserves then will not last until spring.
Like birds, bats also take to nesting boxes. These, however, are only a limited substitute for natural living places; as they cannot be used as winter quarters. The preservation of natural trees is therefore of utmost importance.


Keeping tortoises during the winter

Hibernation is part of the natural yearly cycle of tortoises and should not be denied them. Falling temperatures and shorter days with less intensity of light cause a hormone change, thus bringing about the metabolic process that prepares the animal for hibernation. The tortoise gradually stops eating and its digestion processes finally completely cease. Breathing, heartbeat and metabolic activities are slowed down to a minimum; the animals begin to dig themselves in. A tortoise can hibernate for up to half a year in this condition.

In the wild tortoises prepare themselves on their own for hibernation, digging themselves in outside, too. If they are to spend the winter out of doors, the place must be frost free and safe from mice, rats and martens. Hibernation lasts from one to four months – the further south, the shorter the hibernation period.
If the animal is to hibernate in the cellar, its human friends will take over the preparation. The tortoise should be bathed first, so that it can empty its bowels. The best thing to use for the hibernation box is a mixture of loose earth and leaves, bark compost or something of that nature. This material should not be of the nature and consistence that it might block up the animal's nostrils. It must be kept slightly damp throughout the winter, so that the tortoise does not become dehydrated. The room where the hibernation box is standing should be kept dark.

The following is valid for both methods: only healthy animals should go into hibernation! If the animal needs medicine, a pause of 6 weeks should be given after the medication, before the tortoise starts its winter sleep. When the tortoise wakes up in spring, it should be given another bath. Weigh the animal before and after hibernation. Weight loss is an indication of too dry and/or too warm a hibernation, and should be avoided at all events.


Foundling birds

When the breeding season begins again in April, it could be that you suddenly discover a young fledgling that has fallen out of its nest. Please leave the fledgling with its parents in the wild.
Observe at first from a distance whether or not the parents are looking after the little one. If it remains alone, look for the nest that it has fallen out of, and put it back in there. It does not matter if you pick it up in your bare hand; contrary to the widespread belief, the parents will not shun their youngster if it smells of a human. It will in all probability b e accepted by its parents and looked after again. No one can do this job better than the parents.

It could be, however, that the parents or even the siblings have thrown the fledgling out of the nest on purpose, because it is not healthy, or simply because there is no longer enough space in the nest. If the foundling is not accepted or you are not able to find the nest, contact the nearest bird protection centre. You will find further information there under  HYPERLINK ""


Wasps' nests too close to the house

Frightened or uninformed people who feel threatened by wasps are always contacting the fire station or pest control companies to get them to remove a wasps' nest because they think it is a menace. If the wasps' nest is in a problematic position it is often sufficient to screen off the nest, e.g. by securing the windows of buildings from the inside with wire mesh.
If it is absolutely necessary to move the nest to another place, please contact an expert. You should not try to relocate the nest yourself, both for safety reasons and because of animal protection laws. There is a data bank of experts in the whole of Germany under  HYPERLINK ""



Generally speaking a wasp sting is not of any great danger for a human. Even several stings are mostly unproblematic. They should be cooled with ice or treated with suitable insect creams. Unlike bees, wasps do not lose their stings when the sting someone. If a wasp is swallowed, a sting in the oesophagus can swell up and hinder breathing. In such a case, you should go to a doctor immediately and cool the sting with ice!
For those who are allergic to wasp poison, a sting can be dangerous, as it could cause difficulty in breathing, profuse perspiration and giddiness. If the allergy is already known, the allergic person should always carry the necessary emergency medicine with him/her. If this is not the case, the person should stay as calm as possible and go to a doctor straight away.

An allergy to wasp poison can easily be healed. Ask your doctor for advice on treatment. It has been scientifically proved that a hornet's sting is not any more dangerous than a wasp or bee sting. Here, too, the sting is far more dangerous for anyone who is allergic than for those who do not have an allergy to hornet poison. Only those are endangered, however, who have already suffered a hornet sting. It is possible for a strong allergy to develop only after several stings from the same type of animal.