PROBLEMS WITH BATS IN YOUR HOUSE? ADVICE TO HOUSEHOLDERS

Transcription

1 PROBLEMS WITH BATS IN YOUR HOUSE? ADVICE TO HOUSEHOLDERS

2 Contents table Contents table... 2 Introduction... 3 Nuisances... 3 Bats in rooms... 3 Noise... 4 Droppings and smell... 4 Damage... 4 Disease... 5 Household maintenance... 5 Repairs, re-roofing and alterations... 5 Remedial timber treatment... 7 Timing of works... 7 Emergencies... 8 Licensing options... 10

3 Introduction Houses play an important role in providing suitable roost sites for several species of bats and retaining bat roosts in houses is essential for the successful conservation of these species. We endeavour to respond to the concerns of householders who have bats and, through our contracted and voluntary bat workers, provide practical and helpful advice on how to deal with these problems. Free roost visits are only undertaken by SNH bat workers in cases involving enquiries from householders. These are members of the public who own, rent or occupy a property, i.e. they are living in the property. In all other cases, such as all commercial premises, public buildings, large hotels, schools, hospitals etc, we will not normally undertake roost visits but will provide verbal and/or written advice, with the recommendation that a specialist bat consultant is employed to advise further as necessary. Concerns about bats in houses tend to fall into one of the following categories: Nuisances such as noise, droppings, smell or bats flying around in rooms; Maintenance, building work or timber treatment is required; or Risk of disease. Nuisances Bats in rooms Bats generally come and go from their roosts without any trouble, but occasionally they appear inside the house. This seems to be most common when baby bats, which are tiny and often grey, crawl out of their roost and find a way into the rooms. There are also cases of young, inexperienced, bats flying in through windows by mistake. If a bat is flying inside a room, open doors or windows to allow it to escape. If it has settled, and remembering you should not touch bats, phone the Bats in Houses Helpline or batsinhouses@snh.gov.uk or phone our out of ours service You can also phone the Bat Conservation Trust National Bat Helpline on Further information is available on our website If you need to remove a bat from a room

4 or anywhere else, place a small box or other container over it and slide a piece of cardboard underneath to trap it. Alternatively, cover the bat with a soft cloth or towel and gather it up carefully. In both cases you should wear protective gloves. Carry the box or cloth outside and release the bat away from houses, cats and people, preferably at dusk. If more than one bat appears inside, it is most likely that they are crawling through from a roost, so block up any holes around pipes or gaps in ceilings or floors from inside the house. If you are not sure what to do, phone the Bats in Houses Helpline or your local bat group for advice. Noise Problems of noise can occur occasionally; if they do, then specialist advice may be needed. Large colonies of pipistrelles can be noisy during the summer, especially if they are within the wall of a bedroom. While this may last for only a short time it can be disturbing - we can advise on possible solutions that will help both you and the bats. Droppings and smell Bat droppings can be unsightly, though in Britain there is no known health risk associated with them. In the loft, the simplest and most cost-effective measure is to cover stored goods with dust-sheets, which can be brushed off every now and then. Outside, droppings stuck to the wall and windows are usually only a seasonal problem, but if a remedy is required, deflector boards fitted above windows and doors can provide a solution. Bat droppings do not normally smell strongly, but may do so if they get wet, either because they are in a very confined space with little ventilation or because rain water is entering the roost and the building. Damage Damage to property from bat droppings/urine can occur, but this is very unusual. Unlike birds, bats do not bring material in to build nests and, unlike mice, they don't gnaw wood, electric cables, or entrance holes; they merely take advantage of existing gaps or holes. Once inside the roost they cling on to the timbers or squeeze themselves into cracks and crevices. Most bat colonies are small, with a colony of 50 bats weighing in at well under 500 grams. As cases of damage are rare and likely to involve unique circumstances, a visit by an SNH bat worker will usually be required to help devise a solution.

5 Disease British bats have few diseases that could affect humans and problems are very rare indeed. In recent years a tiny number of bats have been detected with a rabies-like virus called European bat lyssavirus (EBLV), which can infect humans. For this reason, you should not touch bats or have contact with bat saliva. Bats rarely come into contact with people, but if you are bitten or scratched by a bat, you should wash the wound thoroughly with soap and running water for at least 5 minutes and seek immediate medical advice. An effective post-exposure rabies treatment is available. Even if you have bats in your roof, there is minimal risk to you, provided you do not handle them. In Scotland, a small proportion of Daubenton's bats have been found to have antibodies to EBLV indicating past exposure to the virus. Only two Scottish Daubenton's bats have been found with evidence of the virus itself. For more information see and Household maintenance Because they depend so much on buildings, bats need our tolerance and help to survive. This is mainly a matter of leaving them undisturbed. However, repairs, maintenance and alterations to buildings can adversely affect bats and their roosts. In these cases, a little forethought can minimise the problems. Remember it is illegal to damage or destroy a bat roost even accidentally. Repairs, re-roofing and alterations If you think you have a bat roost and want to carry out maintenance or repair work to your property that might affect the bats, please contact Scottish Natural Heritage for advice before starting the work. Typical maintenance and repair scenarios include: repairs to roofs, eaves, gutters, soffits or cladding, exterior painting, wall repointing, laying boarding or insulation in the loft, plumbing or electrical works in the loft, remedial timber treatment for wood-boring insects and other loft alterations. You may need a licence to carry out the work if it cannot be done outside the bats' breeding season. You may be asked to leave access points so the bats can return in the following years. Although some of these cases will need to be licensed, others can go ahead subject only to certain constraints (e.g. on timing), following advice from SNH. Provided the work can be undertaken at a time of the year when the bats are not present and it will not result in any damage to the roost area or loss of bat access to the roost, there is no need for a licence.

6 If the work cannot be undertaken without impact on the bats or their roost, you will need to apply for a licence from SNH. If you wish to proceed with a licence application, you may need further specialist advice. An ecological consultant can assist with this process see SNHemployed bat workers are not available to fulfil this role. Table 1 Some typical household maintenance scenarios are shown below. Note that you should still consult SNH for advice before undertaking works that may affect bats or their roost. Proposed activity Standing advice from SNH Remedial timber treatment in a domestic property for maintenance repair or refurbishment purposes. Carry out the work at a time of year when bats are least likely to be present. Use a product that is not known to be harmful to bats. By carrying out the work at a time when bats are least likely to be present, and using products acceptable to SNH, the company should avoid committing an offence disturbing, killing or injuring bats or damaging or destroying roosts. Repairs or redecoration of gutters, soffits, bargeboards etc. close to the entrance to a bat roost. Carry out the work at a time of year when bats are least likely to be present. Ensure that roost entrances are not blocked or altered. The timing should ensure that bats are not disturbed. The roost will not be damaged or destroyed. Re-roofing for repair or refurbishment. Carry out the entire work programme at a time of year when bats are least likely to be present. Ensure that roost entrances are not blocked or altered and that the places where bats roost are not altered. Ensure that any roof coverings, including underfelt, are appropriate. If this advice can be followed, no offence is committed and so no licence is required. However, if the timing of works includes times when bats may be present, or if the roost entrances or roosting places will be altered, a licence may be necessary. Sometimes there will be cases that fall on the borderline between a licensable act and one that is not. In such cases, you should err on the side of caution and apply for a licence. It is your responsibility, as the householder, to ensure that you work within the law.

7 Remedial timber treatment Treatment of woodworm or rot can be a major hazard to bats if carried out with the wrong sort of chemicals or at the wrong time of the year. Older-type insecticides such as lindane leave poisonous deposits on the treated surfaces which can kill bats even if they're not present at the time of treatment. Fortunately, this situation has now been improved by the introduction of more modern insecticides like permethrin or cypermethrin, which are much less poisonous to mammals. However, timber treatment should not be carried out when bats are present. If you think bats use the building, tell your timber treatment company and see for a list of approved chemicals (including fungicides). You should also request advice from us on how and when the treatment should take place. Timing of works Where work is proposed that will unavoidably affect bats or their roosts, it should be programmed to take place when the bats are not present. In general, works affecting a summer roost such as a maternity roost, should normally only take place between the months of October to March inclusive. There is some flexibility in this general guideline, such that in some circumstances, notably where major roof repairs are required, work may only be practical during the spring or late summer/early autumn to avoid the worst weather of the year. In such cases, SNH will endeavour to provide helpful and pragmatic advice. A building or structure that has been identified as a hibernation site should not be disturbed during the period November to March inclusive (this period may need to be extended, according to the weather conditions) and work may only take place in the remaining months of the year. There are other types of roost that have a more transitory function, for example, in the spring and autumn months and often require specific solutions. Work in mating/swarming roosts should not take place during August to October inclusive. Weather conditions in the spring and autumn affect these general recommendations, such that a cold wet spring will delay when female bats return to the maternity roosts and, likewise, if the autumn is particularly cold, bats will enter hibernation earlier. More information on activities affecting bat roosts and the recommended timings that apply can be found in chapter 8 of the Bat Mitigation Guidelines, see aturalengland.org.uk/publication/69046?category=31008.

8 Emergencies Advice about bats should be sought well before any proposed building work. However, occasionally a situation arises involving an active bat roost where immediate action must be taken irrespective of the bats circumstances. Serious problems are rare but may include the following situations: Roof repairs - bats are found after the work has started: if bats are found to be present in the building or evidence of their use of the building is found, all building work should be temporarily suspended and SNH contacted immediately for advice Timber treatment - bats appear after spraying has begun (as above, i.e. suspend work and contact SNH for advice) Intolerable smell Intolerable noise If work must be carried out while bats are still present and are likely to be disturbed, or the work will result in damage or obstruction to the roost, a licence will need to be issued by SNH before the work can continue. When dealing with these scenarios, the aims should be (in order of importance): 1. to ensure that bats are not killed or injured 2. to ensure that the bat roost is not damaged or destroyed 3. to ensure that the bat roost is left for the breeding season 4. to ensure that the bat roost is left for the future A major consideration is whether or not there are non-flying dependent young present. Dependent young may be present in the roost during the months of June, July and August. Any attempt to exclude the colony before all the young are capable of flight is likely to result in young bats become trapped and then dying slowly as the mothers swarm around the building attempting to get back to them. If any young bats are present and capable of flying, the licensed exclusion of the colony by means of a one-way excluder is possible and should, therefore, avoid any mortalities. This process is sometimes known as an early exclusion. The licence will specify the method to be used and whether it must be undertaken or supervised by an experienced, licensed bat worker. Note that this course of action is also likely to result in prolonged swarming behaviour around the house over successive nights as the bats try to gain entry, so it is always preferable to wait until all the bats have naturally dispersed and left the roost before

9 attempting a licensed exclusion. In practice, this is often only a few weeks after the earliest date at which an early exclusion can safely take place. If you wish to exclude the bats, a licence will be required from Scottish Natural Heritage, see Note that the minimum level of species information required on the roost report form (to be submitted in support of the licence application) is: Species Roost type/status Numbers (estimate) Please note that it can be very difficult to make some buildings bat-proof. This is particularly true of older houses with complex roof structures.

10 Licensing options Where the householder is unwilling to tolerate the presence of bats in their house, it is important to determine the reasons for this. Some of the reasons for objecting to the bats can mean that a licence needs to be issued to exclude them. Investigation of the roost, or discussion with the householder, may reveal one or more of the following scenarios that leads to this: Table 2 Scenario Licensing purpose and action There s a strong smell of bats or the noise from the roost is keeping family members awake. Public health. Licensed exclusion of the bats at an appropriate time of year may be an option. In the short-term, improving ventilation may help reduce a smell problem. The householder has a genuine phobia about bats, expresses a fear of bats or is clearly worried and anxious about their continued presence. This could affect the health or well-being of the householder. Public health. Licensed exclusion of the bats at an appropriate time of year is a possibility. In particularly severe cases, more immediate exclusion of the bats may be necessary, though the period when non-flying young are present should be avoided. Accumulated bat droppings and urine are causing damage to the building, most often by causing internal staining. This problem may be coupled with a smell problem. Damage is likely to continue unless remedial action is taken. Preventing serious damage. This is relatively rare. Ideally, a solution will be found that will enable the bat roost to be retained if the necessary remedial works can prevent a recurrence of the problem. Parasites associated with the roost are entering the property and biting the householder. This is uncommon. Public health. Exclusion of the bats may not be necessary depending on the advice of the pest control specialist. An approved insecticide treatment for use in/near bat roosts must be used (see list). Bats are found by the householder in the living area of the house. The most common situation is baby or inexperienced bats crawling from their roost area into the living area. If these bats are not rescued from within the living area they are likely to die of dehydration or starvation. Unless a reoccurrence can be prevented, it is in the interest of the bats for them to move to a more suitable roost. Conservation. The primary action is to locate and block the point of entry of the bats to prevent a recurrence of the problem. (This does not require a licence.) In rare cases this cannot be done, perhaps because of the age or construction of the building, so excluding the bats under licence is the only way of preventing further deaths. For more information about licensing please call SNH Licensing on