Tag: bats

Cilfái: Woodland Management and Climate Change on Kilvey Hill, Swansea ISBN 978-1-7393533-1-5

This has now been reprinted as a 2025 Second Edition with some updates I’ve also updated the copyright for AI constraints, and EU product compliance details.

This book started out as a collection of notes made over more than a decade of surveys in Welsh woodlands. What started out as a historical investigation into industrial archaeology in woodlands transformed into a catalogue of what climate change, government policy and local politics is doing to our landscape. As I write this Cilfái is threatened once more with proposed transformation that increasingly looks like destruction.


This is a companion volume to Cilfái: Historical Geography on Kilvey Hill, Swansea. But this one is more about the environment of the woods and the climate change that is already changing the nature of the land. Climate change is now part of life and the next generation will be challenged with adaptation to what is happening. This book is my chronicle of what some of that means for Cilfái (Kilvey), this most special part of Swansea’s character that has been abused, ignored and loved…depending on where you live and what your politics are. Some of this work is based on my government experience as a programme reviewer of many environmental and cultural projects across the UK where I experienced the good, the bad, and the ugly of politicians, the Civil Service and successive government policies or the lack of them.


Authors always have inspiration from somewhere and I am no different. My inspiration has been in the conversations and actions of many colleagues in my time working in UK Government in Defra, MOD, Cabinet Office, and Parliament. They all contributed, sometimes unwittingly. You can often learn a lot about a topic by listening to people who know very little about it but who never feel restricted in holding an opinion. Climate change is one of those topics.
I have been privileged to have had the company of experts in many conversations about the topics covered here. But notably, the Forestry Commission was laid bare to me by veteran forestry man David Connick. Equally, the passion of my friend Keith Clement in worrying about where we are going has constantly coloured my sense of urgency.
The commitment and enduring engagement of the Kilvey Woodland Volunteers never ceases to amaze and inspire, and I regularly see incredible generous acts of sharing and care for the Hill that should be an example to all volunteer groups.

I produced or maspped a lot of data (both historical and current) using QGIS. Here you can see the 1980s woodland compartments and their relationship with the original industrial waste tips.

Woodland Resilience

I talk about ‘Resilience’ in Chapter Three of the second Cilfái volume.

The term ‘resilience’has become a key concept in our landscape management. Resilience in woodland is becoming a broader and more important topic as climate change starts to bite.

In its current form, Cilfái is resilient. Yes, people burn it every year, but that results in more biodiversity hotspots as the burnt patches grow back with local species of trees and vegetation that are much more resilient to fire and drought.

Anything done to the woodland should be to enhance resilience…not knock it back with imported plants, plastic tree tubes and high maintenance planting schemes.

Diversity in the Cilfái woodlands can range froim genes and species to habitats and landscapes. The complexity of the Cilfái woodlands ecosystem will always be limited compared to a woodland that is older or has not been polluted. Still, the pollution history of the hill makes the ecosystem special and probably even unique.

Above: The seaward slopes of Cilfái are increasingly susceptible to windstorms which easily topple the trees that often have poor anchorage because of the soil conditions. The resulting deadwood (both prone and standing) provides useful food and shelter for many animals and insects. The natural regeneration quickly takes over a windblown space and colonises fast with the ‘Cilfái mix’ of local species. Incredibly, this site on the proposed tourism development is a bat hotspot. (Author’s collection).

Bats over Cilfái

One of the reasons we know so little about the abundance or distribution of bats is the general technical difficulty of surveying and recording where they live and where they hunt. Nationally, the effort to monitor the bat population is significantly bolstered by the invaluable contribution of volunteers. Their dedication, although often underappreciated, plays a crucial role in our understanding of bat populations. However, this reliance on volunteer work, while commendable, is not without its challenges. The situation is further complicated by the need for specialized equipment and training. Although bat surveys have become a regular requirement for planning permission, the surveys remain expensive and knowledge is considered commercial and rarely shared, making understanding of bat distribution even more complex. Using specialist recording equipment means the data files for bat surveys can become very large very quickly, although the advantage is that the data is available for further analysis and verification.

I trained as a bat surveyor in the Thames Valley, where University researchers waxed lyrical about the high densities of bats along the river. One warm night we went out and didn’t detect a single one. That has never happened to me on Cilfái, where bat presence can be staggering on many nights.

Bat surveys have become high cost as surveyors seek to extract as much income from the work as possible. It is unfortunate, as much needed information then becomes restricted or unshared. That greedy attitude led me to share as much as I have on the bat presence on the hill in the second Cilfái book. Cilfái: Woodland Management and Climate Change on Kilvey Hill, Swansea.

On Cilfái, I use a combination of a handheld detector and automatic recorders, which give me a sample of several nights at various locations. This lets me hear the bat calls as they hunt and analyse the recordings at home. I use the classic handbook for techniques Jon Russ wrote (Russ 2012). I use Anabat Express (or equivalent) passive bat recorders and process the data with Anabat Insight Version 2.  Over time, this gives me an understanding of the ‘hotspots’ of activity across the hill. I only get snapshots of what is happening, and I cannot realistically project what I know into the overall picture of bats on the hill. That will take a few years. I can assume that our ‘Year Zero’ in 1970 had no bat presence and that everything I see and hear in 2023 is the product of fifty years of recovery. However, realistically, the woodland only began its recovery in the mid-1990s.

The hotspots on the hill are where the food is. Generally, these are the open spaces where previous burning or wind damage has opened up the forest canopy and allowed a wider range of native plants to prosper. Some of these open spots are also good for birdlife. On a warm autumn evening, the air in the hotspots is thick, and flying insects attract the bats. I have evidence of a large presence of Common Pipistrelle (Pipistrellus pipistrellus) and Noctule (Nyctalus noctula). It is possible that hidden in my recordings is some evidence of the Brown long-eared bat (Plecotus auritus), only further data collection will confirm.

Although I can track and monitor activity, it remains immensely difficult to understand hibernation and roosting sites. I am slowly building up a library of bat presence data across the hill.

Russ, John. 2012. British Bat Calls: A Guide to Species Identification (Exeter: Pelagic).

Below: Although it looks a bit technical, it is the nature of bat survey work that we prepare this kind of evidence. The land above Foxhole and the Glade is very busy with bats and clearance of trees will definitely cause problems for the population that has re-established up there. On the night this recording was made I had hundreds of similar records. You can see more evidence in the Cilfái book.

This is a recording of a Common pippistrelle hunting on the woodland edge above Foxhole in September 2023. Temperature above 20 Celsius (Analook F7) compressed with split-screen option Cycles, showing the characteristic call shape of a hunting pippistrelle.

Below: Me bat surveying on the threatened land above Foxhole September 2023

Saving the Environment: The importance of Information

When I worked for the Government, I did some tours of duty in environmental activities. Over the years, I monitored programmes on the health of Honeybees, parks protection in Greenwich’s ancient woodlands, Restoration of the environment in the Olympic site in East London, and several small conservation programmes on security sites for the MOD, where fencing things off from the general public did wonders for the local biodiversity. In all of that, I learned that data and information are vital. Far too often I heard the comment ‘there’s nothing there!’, often from gentlemen in their fifties whose only interest in nature was how to kill it or cut it down. When I got to a position of some influence, I could slow down or even reverse developments by insisting on a good quality ecological survey before any construction work. Sometimes, this was deeply unpopular as the construction industry usually has little interest in conservation or environmental care…what we see of due diligence by building firms is there because the Law forces them. This will definitely be an issue in Cilfái with the Skyline development. That tourist firm will promise anything in the planning permission stage but quietly ignore it in the building phase, knowing very well that Swansea Council does not have the resources to monitor and enforce anything. We as volunteers will need to monitor the destruction to try and ensure it is kept to the promised minimum. In December 2022, I prepared the first of a series of ecological protection documents based on my time in Whitehall. The key one is called an Ecological Constraints and Opportunities Plan (ECOP for short). I did one for Cilfái based on what we knew at the time. It proved quite popular and still is, judging from the large number of downloads it still gets from all over the country. Eventually, the ECOP evolved into the second book Cilfái: Woodland Management and Climate Change on Kilvey Hill, Swansea. I published all my survey notes and plans going back over about ten years of tree and animal survey, including all my work on the Hill. So, the book has an explanation of the data covering the Hill and lists of bats, birds, plants and animals I found or saw presence of. I also included the wonderful observations made by Carl Squires over many years of walking the Hill. I also added some of my Climate Change risk analysis from my time working for UK Parliament. Below: A mash-up of some of the Cilfái data from my surveys and explorations.  It is complex because ecology always is. The red dots are dead or dying trees, the dotted lines and light green stripes are areas for better bird habitat, Yellows and oranges are different types of open land, and darker greens are the Forestry Commission plantation trees. The red lines show the ghost of the coming area of Skyline destruction.