Peregrine falcons arrived on Derby Cathedral's tower unaided in 2004 – we did not attract them here. But in 2006 they showed signs of wanting to mate, so the project partners decided to offer them a more suitable place to nest than the small ledges they were trying to use on the cathedral's stonework.
Here are some technical details of our nest and camera installation which we hope may be of interest to others considering such projects.
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Nest Platform and Webcam Location
The peregrine nest platform and its two webcameras are positioned half way up the east side of Derby Cathedral’s ancient tower. They can only be reached by abseiling on a rope from the top of the medieval tower. Derby Cathedral is in the northern part of the city of Derby, between Irongate and Full Street. Derby itself is in the East Midlands region of England, and has a population of around 200,000.
Follow this link to Derby Cathedral's website.
Platform Construction
The nest platform is a wooden structure about the size of an office desk (approximately 4 foot 6 inches wide by 2 foot deep). It was designed and built by mountaineer and joiner, Nick Evans, and installed by him and N. Moyes of Derby Museum on 5th April 2006 in such a way that no 
damage was done to any of the cathedral's stonework. Extra long ropes and back-up for the abseilers was provided by Derby Mountain Rescue Team. The platform is fitted entirely into the wooden, louvred bell-tower windows, and was designed to last at least three seasons before needing replacement. After its third annual inspection in 2009 it was found to still be in extremely good condition, still capable of taking nearly the full weight of a person. However, one of the two original supporting metal straps has since been removed when the cameras were installed as it would have severely obstructed the view.
The platform is made from 3/4 inch thick Oriented Strand Board (OSB), also known as Sterling Board. It is divided into two equal partitions. On the left side, and watched by camera 1, is a 3-inch deep layer of pea gravel. The right side holds just a thin layer of slate chippings, and is watched over by camera 2. To prevent the timber from rotting prematurely, the gravel lies over a woven plastic sheet, held off the timber base by a thick, coarse plastic mesh. Drainage holes in the base then let water escape. The two large holes in the rear panel are sometimes mistaken for nest holes when seen from below; they are simply holes used to attach haulage ropes when raising the platform into position.
What were the risks? A downloadable copy of our Method Statement and Risk Assessment document for the camera installation day will soon be available on this site.
Design Considerations
Initially we had no idea if the peregrines would use an artificial ledge, so it had to be made quickly and at low cost. It was positioned on the east side of Derby Cathedral tower, directly over the nave roof, for various reasons:
- it is in the lee of prevailing winds;
- any faeces and prey remains fall over the nave roof, not over the street or main entrance;
- this has minimal visual impact on the listed building. It cannot be seen from key vantage points such as Irongate, Queens Street or St Mary’s Street, but can nevertheless be clearly watched from the rear of the Cathedral. i.e. from Full Street/Cathedral Green;
- Installation on this side posed no risks to the public below.
The platform and, later, the web cameras were coloured to the background stonework of the cathedral, and the cathedral architect demanded that no drilling or other damage would be done to the ancient stonework. Guidance was also sought from the Built Environment Team of Derby City Council who have experience of works on listed buildings, and gave freely of their advice.
Webcam Details
Two webcameras were installed in 2007, and a third was fitted in 2008. Two are mounted on poles at either side of the nest platform so as to give a view into both halves. The cameras and associated cabling were supplied by EcoWatch, but were installed by our own team members. Once again, Nick Evans gave valuable assistance in making the mounting poles and abseiling down to help fix them in position. All nest maintenance has to be done before early-March when the birds start to nest once more. Any disturbance to an active peregrine nest site would be illegal.
Camera 1 looks down to the left-hand side of the platform with its gravel nest scrape. When fully zoomed out, a small portion of Amen Alley is visible in the bottom left corner. It is a Panasonic WV-CZ352 which can be remotely zoomed and focussed from inside the tower. It is a 530TVL camera, with a separate infra-red illuminator beneath it to allow night-time viewing in black and white without being visible to the birds or causing them any disturbance. This camera came supplied with a hand-controller to allow adjustment to zoom and focus from within the tower. We were later able to build a simple relay device to control the camera by using the remote switching capabilities of the Axis video server. (Our thanks to J. Salloway for this). At first this could only be done from one laptop inside the Museum, but later a Virtual Private Network (VPN) was set up to give 24 hour access and control from the home PC of one of the staff involved in this project.
Camera 2 looks down to the right hand side of the peregrine platform. A small part of Full Street is visible in the top right corner of its picture. Acting on advice to minimise the visual impact of our cameras, we chose a smaller model with slightly lower resolution. It has an in-built infra-red illuminator and microphone. Its focus is fixed and we are fully aware that the night-time image is slightly out of focus, but we cannot alter this whilst the birds are nesting.
Both cameras switch automatically to night vision when light levels are low. Each is fitted with flexible anti-perching spikes to discourage the birds from landing on them. These were supplied free of charge by the Pest Control Department of Derby City Council. The cameras were supplied with black mounts and any other light-coloured items such as CAT5 cables and bird spikes were also sprayed black to reduce visual impact on the Cathedral.
We asked for cameras to be supplied pre-fitted with 15m of cabling so that they could be fed in from the outside and dropped drop down into the bell chamber below. They then plug into a further 25 metres of cable going down through two more floors to the bell-ringing chamber, where monitoring and internet equipment is installed. Luckily, we could use existing cabling routes for our wiring, so no structural damage occurred at all. We experienced difficulty in finding camera supporting brackets of suitable quality and resorted to Loctite-type products to keep screw threads done up.
Camera 3 is mounted at the very top of Derby Cathedral's tower and looks out across three "gargoyles" on which the peregrines like to feed and roost. It is a small, outdoor quality dome camera with an auto-iris facility, variable focal length lens with infra-red illuminator. It slots through a rainwater drainage hole and can be removed and replaced without causing any disturbance to the birds. We purchased the cabling, but wish to acknowledge the generous donation of the camera itself by Acam Technology Ltd. In its first year the night-time image suffered severe flare from the infra-red illuminators, but this was reduced in 2009 by careful masking with adhesive tape to improve image quality.
Getting the Images Out
The video feed from each camera and a microphone goes to an Axis 241QA video server supplied, purchased from and supported by Network Webcams. This converts the analogue camera signals to a digital form and, if desired, can act as a web server, sending images directly out to the internet. It also has the capacity to process a total of four camera signals and one microphone, and we have been delighted by its functionality, especially the ability to use it to remotely zoom in Camera 1 via the internet.
A Philips DVD/HDD Recorder (model DVDR3460H) was loaned by the BBC TV during 2007 and replaced with an identical model in 2008, (We call this DVDR1). It has a 250GB hard drive takes one of the two camera signals and records this in 6 hour chunks to a hard disk drive, set to "SP", or standard quality, which is suitable or television broadcasting. Up to four days of footage can be stored and reviewed, and key events edited and dumped to DVD disk before further recording overwrites what has already been made. Footage can be reviewed in 5-minute steps, and a diary summarising the events of those past four days is kept. Important clips can also be "protected" so that they remain on the hard drive and are not overwritten. This is a useful facility as it allows all the protected tracks to be copied to one or more DVD disks at the conclusion of the season. Output the DVD recorder goes to a TV monitor inside the tower. Single video clips destined for YouTube were saved onto DVD-RW disks. These did not need to be "finalized" and the video filename simply needed changing from .VOB to .MPG prior to uploading. Video clips for use on other DVD players were burnt to DVD-R disks and had to be "finalized" - an extra process taking a number of minutes, so adding to the overall time taken to capture images.
In 2008 our set-up became rather more complicated when donations to the project allowed us to install a third webcamera and to purchase a second DVD/HDD recorder, also a Philips DVDR3460H (we call this DVDR2). We needed a video switch to allow us to manually select which of the two nest camera signals goes to DVDR1 for recording. The tower camera signal goes direct to DVDR2. As we have only one TV monitor inside the tower, we also needed to install a Scart switch to select which of the two DVD Recorders' outputs is displayed on screen. The switch box we chose happened to have an RGB on/off switch which actually improved the picture quality on our initially rather cheap TV set. Being identical models, one DVD Recorder had to be stacked at right angles to the other to prevent operators accidentally controlling the wrong unit with the remote control.
Normally, a video distribution amplifier (DA) would be used on each video channel to divide and amplify the signal, before sending one half to the video server and the other to the DVD Recorder. We found that Camera 2 worked well with a Kramer DA box, but that Camera 1 would not function at all with it. So instead we used a simple signal-splitting phono adapter on each camera feed. This can often cause ghosting of the signal, but we appear to have got away with it, which was most fortunate. For this reason we decided to replace the DVD recorder loaned by the BBC with identical models in the hope that pictures would remain of good quality.
The audio signal was found to reduce significantly when split prior to going to the video server. Each DVD Recorder has an audio pass-through facility; this allowed us to plug the microphone directly in to DVDR1, then take the audio output and connect it straight to DVDR2, from where that second machine's audio output goes to the Axis video server. We found the microphone to be very sensitive, easily distorting with loud sound (like church bells!). The slight loss of audio signal on pass-through was therefore not of any concern.
The Axis video server then connects to an internet switch and then to the Council’s network. At the time of installation the cathedral had no broadband connection, so we managed to beg use of a Cisco 1200 series wireless access point was installed to connect us to Derby City Council’s network, via a link inside Derby Industrial Museum. The yagi aerial on the cathedral was positioned very low down above the nave roof, so as not to be visible from street level. The wireless unit in the Silk Mill was mounted inside the building, with its small yagi aerial pointing through a closed window towards Derby Cathedral. That signal then goes via a pre-existing laser link to Derby Assembly Rooms, and thence to the City Council’s network. The wiring diagram below shows how our switches, camera feeds and video recorders are currently configured inside the Cathedral bell-ringing chamber.
The moving video stream is sent through our Council's corporate firewall to Streamdays.com who then serve the video stream to you, our public internet users. Unfortunately their Streamdays Relay service does not carry audio. The internet images are refreshed at a rate of about 1 image frame every 6 to 9 seconds for broadband users. Had we tried to use our Axis video server to serve the picture stream directly to users we would have faced two problems. Firstly, it is limited to 20 users at a time, which would have been wholly inadequate for the demand we receive. Secondly, our Council's security policy would not have permitted external users through our firewall to view the video server stream directly. The technical configuration of our video server and wireless access equipment was undertaken by experts from Capita - the City Council's IT consultants.
At a future point we hope to be able to serve images from the City Council’s own servers, but this is not possible at present.
Lessons Learnt
2007 was our first year of providing webcam images of the peregrine falcons, and we had a steep learning curve.
Fully test all cameras, cabling and remote control equipment well before installation. Don’t assume that the camera settings will suit your needs, or even that BNC plugs will have been connected correctly (give each a sharp tug!). Test everything beforehand. (We found it challenging to have to change a camera's menu settings whilst dangling from a rope outside a building when the monitor is inside and three floors below!) Test and ensure that camera brackets are of sufficient quality to hold the cameras in position. Locktite is recommended for use on brackets that aren't sturdy in their design.
There was a huge public interest and support – take advantage of it!
Within a local authority there can be many services, skills and resources available which can be freed up for a popular project such as this. Despite all the planning, working practices can still impose unexpected delays; try and identify all steps in the process and ask about likely delays in advance. Talk to IT, Building Control officers, Health and Safety well in advance. We started planning in October, and then began our work in earnest in January in readiness for nesting in late March. This only just gave us enough time to get it up and running.
Professional installation of our webcameras would have cost us nearly £2,000. By doing it ourselves, and using the skills of local mountaineers (one of whom was also a joiner) we were able to control the project in far greater detail. We now have a more intimate knowledge of how the equipment works, and can maintain most of it ourselves. We experienced difficulty in finding camera supporting brackets of suitable quality. Small, low-profile brackets usually had poor locking mechanisms, causing cameras to slowly droop over time. Stronger brackets all seemed too rugged and too large for our purposes.
Talk to planners and those advising on listed building consent well in advance, Although decisions on some structures placed on ecclesiastical buildings are in the hands of the church authorities, the planners can nevertheless offer much support and advice, especially in minimising the visual impact of any nest ledge. Do nothing which could cause architects, health and safety officers, and especially the owners of the building to feel that your project is taking them for granted. Our project takes pride that we have encountered no such difficulties along the way, despite the many opportunities for causing other people considerable annoyance.
Working as a partnership brings benefits and new audiences to all parties. Each brings skills that one organisation alone may be unable to supply. Without the combined support of the Derbyshire Wildlife Trust, Derby Cathedral and the City Council's IT and Museum Service, this project would not have succeeded.
Remote internet access by project staff to the video server is a boon. It allows an easy reboot of the server at any time of day/night should the image stream fail (which happens about once every two months). The ability to remotely control a camera's zoom and focus adds an extra dimension and variability to the images shown. A Virtual Private Network (VPN) was created by the Council's IT agency so that 24 hr access was available to one of the project partners to control the server and cameras. It has been well-used.
Many users do not have Flash Player installed on their computers, nor are they able to view YouTube video clips. Nevertheless these gave a quick and effective way of sharing our images with many thousands of visitors. Access to online blogs are blocked by many schools ICT monitoring systems, but can be opened up if you make a formal request.
Suppliers and Costs
The following is an approximate breakdown of costs incurred and the providers involved. * UK Purchase tax (VAT) is excluded where an asterisk is shown.
We have not attempted to cost the hundreds of hours of time freely donated by staff involved in this project, or the many other helpers who have made this scheme work.
Services used for Peregrine Webcams
| Service |
Service provider |
Cost |
| Camera 1 & 2, microphone, IR illuminators, cabling |
Eco-watch.com |
c£2,700 * |
| Camera 3 (outdoor dome with IR) DVC401 |
Acam Technology Ltd |
gift |
| Cabling & PSU for Camera 3 |
Acam Technology Ltd |
£88 |
| Axis 241QA video server |
Network Webcams Ltd |
£540 * |
| DVD Recorders (DVDR3460H) and (DVDR3440) |
GB Electrical (via Ebay) |
£200 |
| 19” TV monitor |
anonymous |
gift (c£170) |
| Cisco 1200 series wireless bridge |
Derby City Council Highways Department |
gift |
| Wireless bridge relocation |
Phoenix |
£250 * |
| Internet switch |
Capita |
loan |
| 2 Capita IT man-days |
Derby City Council |
gift |
| Nest Platform materials |
Derbyshire Wildlife Trust |
£60 |
| Platform design, installation |
in-house/volunteers |
nil |
| Sundries (leads, switches, DVD disks) |
Derby Museum & Art Gallery |
£170 |
| Publicity Leaflet |
DWT/DCC |
c£500 |
| Video hosting (2 cameras for 3 months) |
Network Webcams Ltd (Streamdays) |
£300 |
| Web design/hosting |
Derby City Council/volunteers |
nil |
Some items loaned to us in 2007 have since had to be purchased to enable us to continue and develop in 2008. Any of the three project partners is able to accept donations for use solely on this project. By far the greatest cost of running this project - were it to be fully calculated - would be the time input we have all willingly put in to install cameras, to run blogs, maintain websites and organise and run watch points. We are grateful to all those who have so generously given of their time and enthusiasm, and for those who have donated to the project. This has allowed us to buy a range of supporting equipment such as telescopes and binoculars, as well as to make a small "thank you" contribution to some of the key helpers who were critical to the success of this project. (Note: the Project Team members themselves receive no financial benefits of this sort)
Visit our Peregrine home page (section 6) for details of who has supported or funded us so far.