CCTV for bat surveying and monitoring

In my work as a wildlife photographer I have met many bat specialists and have often sympathised with the amount of antisocial night work involved in surveys. As my background is in physics and engineering, I have always found technology exciting, and have combined my interests to develop a portable CCTV system for bat roost monitoring that can reduce the need for human presence during emergence and dawn swarming surveys or bat monitoring near roosts.

 Barbastelle bats dawn swarming

The portable system I have developed works well in woodland, but can be used in buildings or caves. If mains power is present, there is even more flexibility and the possibility of obtaining HD quality videos. With power and internet availability it is even possible to view remotely.

I have used trail cameras for many years as a way of establishing the presence of wildlife, and reducing the time spent looking for it, but became frustrated with the lack of flexibility and the generally unsatisfying image quality of night videos. This led to me researching CCTV as a method of wildlife monitoring. In order to test out systems in natural environments, I joined Natural England on Dartmoor as a volunteer.

The possibility of using a CCTV system for bat monitoring was always in my mind and it became apparent that, as there was no power, internet or suitable mobile phone signal in the study area, I would have to develop a portable CCTV system that could work reliably and withstand the uncertain weather in a Dartmoor woodland.

Portable CCTV systems for wildlife are not common, except in the large expensive forms used in major projects, so I had to start from scratch. Although the basics of a CCTV system are straightforward, consisting of camera, recorder and power source, finding suitable, reliable equipment is not easy. Small details can mean the difference between success and failure, but I did eventually achieve success.

The Natural England team at Yarner Wood on Dartmoor are part of the Moor than Meets the Eye project, and I was interested to discover that, as part of the project, the Woodland Trust was carrying out research on Barbastelle bats in the Bovey Valley with a PhD student from Bristol University. Luckily the team were interested in my CCTV system and willing to allow me to test it alongside their research. In addition to the CCTV camera, an SM2 bat recorder was set up to identify the bats seen on video. One big advantage of CCTV is that only infrared light is used and there is no bat disturbance. All UK bat species and their roosts are legally protected and should never be disturbed in any way. The biggest advantage, however, is that equipment setup, data collection and analysis takes place during the day and does not involve night work.

One of the roosts being studied was a Barbastelle maternity roost which was within range of the CCTV camera without tree climbing being necessary. Unfortunately the day before the camera was to be set up at the end of July, the bats vacated the roost, and it looked like the CCTV project would fail before it started. However, as Barbastelle bats are known to switch roosts frequently, it was decided to leave the equipment set up until the end of September and hope that the bats would return.

The results were surprising and exciting and yielded a large number of interesting videos. Although the main colony did not return, throughout the period studied there were regular inspection visits to the roost, together with interesting behaviour that was not fully understood.  A large proportion of the visits did not appear to have calls associated with them at all.

In July and August, Barbastelle bats visited, but in September Long-eared bats were frequently seen on video, easily distinguished by the ears and the hovering flight:

The CCTV system performed reliably and gave some excellent quality videos.  The initial hope of an occasional video was greatly surpassed, despite there being no large colony using the tree as a day roost.

Because of the success of the pilot study, a more formal research project was proposed in order to study the call structure of Barbastelle bats in more detail. The research is taking place at present, using portable CCTV as before, together with two SM4 Wildlife Acoustics recorders. Because it is possible to see the bats as well as record their calls, one aim of the project is to measure how calls vary with activity. Another aim is to investigate if there are ‘silent’ visits. Because the roost was occupied by a Barbastelle colony for the first few weeks, there is an opportunity to study behaviour and call structure before and after roost occupation.

CCTV equipment costs less than bat recorders, the only major cost being in battery power for a portable system. I visit the site twice a week to change batteries and SD cards. This level of activity ensures that data analysis remains exciting and avoids the tedium of trawling though weeks of videos and bat calls. It also allows regular synchronisation of bat detectors and video recorder, both of which can drift in time.

Details of equipment and set up can be found in my book CCTV for Wildlife Monitoring (Pelagic Publishing). The book also give details of many other wildlife CCTV applications. For those less technically oriented I give courses for those willing to travel to Devon.

For further information:

www.cctvwildlifemonitoring.co.uk  (A new site under development)

http://www.pelagicpublishing.com/cctv-for-wildlife-monitoring.html

Susan Young

How you can slightly adjust your life to be more bat-friendly

There are many reasons to want to help bats, not least because it’s actually very easy! British bats are crucial to our ecosystems as they can eat over 3,000 insects a night! Large flying foxes in tropical regions help to pollinate fruits and spread seeds to ensure rainforests regenerate and are sustainable. And bat poop, called guano, is highly valued and effective fertiliser. Bats are also amazing subjects to research, echolocation could offer help to the blind and a blood thinning chemical, used by a small number of species of vampire bats, has the potential to form the basis of new medical discoveries!

                One of the easiest ways to help bats is in your garden. British bats feed only on insects (some species will also eat the occasional spider), so a sure fire way to make your garden bat-friendly is to make it insect-friendly first. Plants that flower at night will attract insects at times when bats are feeding. Building a pond, making a compost heap and planting some wild flowers are also great ways of attracting insects into your garden. Wild About Gardens Week is a great way to showcase your gardening abilities and find out more about how to make your garden a bat haven. To be in with a chance of winning our ‘plant a bat feast’ photo competition, take a photo of your plant-display and email it to lmanchester@wildlifetrusts.org any time before November 6^th!

Many species of bat are put off gardens by bright artificial lights (http://www.bats.org.uk/pages/bats_and_lighting.html), especially those that are shining on roosts, access points and flight paths, so reducing these may result in a higher number of bats occupying your garden. However, there are some British bat species, such as Leisler’s bats, that feed on the insects that are attracted to street lamps.

Putting up a bat box is another relatively easy way to help bats in your garden. You can buy one or make it yourself. Visit our website to find out more about installing a bat box. Some species love bat boxes, whereas others tend not to use them. It can take a few years for bats to move in, so this method of making your garden bat-friendly requires patience. You could also create linear features, such as hedgerows or tree lines. Bats use hedges as hunting grounds and as routes to follow to get to other hunting grounds. 

Another piece of advice to cat owners, try and limit the time that your cat is out when bats are out. Cat attacks are one of the most common cause of bat fatalities; it is estimated that over 30% of rescued bats in the UK have been attacked by cats. More than half of the bats that have been attacked die as a result. If a bat has been caught by a cat it will almost certainly be injured.  Even if you cannot see any obvious injuries there is a great risk of internal infection from the cat's saliva. Furthermore, cats will often learn where a bat roost is and catch bats as they leave the roost, putting a whole colony at risk. If your cat does catch a bat, please call the National Bat Helpline on 0345 1300 228. To avoid bats being killed or injured you are encouraged to bring your cat indoors half an hour before sunset and keep it in all night between April and October. If it is not possible for your cat to be in all night, bring it in half an hour before sunset and keep it in for an hour after sunset

British bats are insectivores, meaning that they feed on insects. This means that pesticides and insecticides can inadvertently harm bats. Insecticides are used in agriculture, industry and domestically and can help explain the rise in agricultural productivity in the 20^th Century. However, they have been found to weaken bats’ immune systems, thus making them more vulnerable to diseases, such as White Nose Syndrome. Moreover, during migration or winter hibernation bats may have toxic levels of pesticide concentrations in their brains. This may cause bat populations to drop, which will mean that even more insecticides are required to make up for all the insects that bats would have eaten. You can help to combat this by buying organic products that aren’t made using pesticides and eliminating the use of pesticides in your personal garden.

Honduran White Bats (c) Shirley Thompson

Adjusting your purchasing habits is also a great way of helping bats nationally and internationally. Bats account for over half of the mammal species that are found in tropical rainforests. This means that bats are vulnerable to deforestation. Bats can be highly sensitive to disturbances, such as habitat destruction and/or fragmentation. For example, when a hibernating bat is disturbed, its body temperature spikes upward in preparation for escape, costing as much as a month of stored fat reserve. Not only does rainforest destruction harm the local bats, but it leads to an acceleration of climate change, which harms ecosystems and bats around the world. There are many ways that you can change your eating and purchasing decisions to help avoid deforestation, for example by switching to a diet that relies less on animal agriculture and palm oil consumption. However, animal agriculture has increased vampire bat populations, as vampire bats feed mostly on farm animals in tropical regions Another solution is to be recycled products, which require less timber.

If you would like to do even more to help bats, be sure to visit BCT’s website (www.bats.org) to donate, volunteer or fundraise. If you are in the UK, we would encourage you to contact your local bat group (http://www.bats.org.uk/pages/local_bat_groups.html). Outside the UK there are a number of other organisations such as Bat Conservation International, BatLife Europe (made up of a number of organisations), Bat Conservation Ireland, Bats without Borders and African Bat Conservation

by Angharad Hopkinson, BCT comms intern (@an_gary_)