Nest Watch 2006 - Technical

The Nest Box
The Nest Box was constructed using a mixture of 18mm external plywood and 18mm softwood. The roof has been covered in roofing felt to help keep the water out of the electrics. The design allowed for a false roof which houses the lights and microphone along with the camera which points downwards into the nesting area.

The hole in the front is 25mm in diameter which is what the RSPB recommend for Blue Tits. It is located facing North and hangs on a wooden wall surrounded by Conifers and overhung by an Oak tree. About 20 metres away there are four more mature Oak trees which harbour caterpillars and grubs, and are favoured by birds such as Blue Tits.

There are lots of plans on the Internet for making nesting boxes, and some are listed on the Links page.

**Update
Due to the female being very reluctant to enter the box, the plate was removed. Once removed, she immediately showed more interest and entered the box at 8.30am the following day. The diary entry for 2nd March 2006 shows what happened.

The perch was also removed, as apparently this hinders wing flight for entry. See the diary entry for 18th February 2006 for a full explanation.

Nest Box Colour Camera, Lights and Microphone
This year we have used a high resolution colour CCTV camera fitted with an F1.4 3-8mm lens. The camera runs at 240 volts from the mains, and produces a 625 line picture.

The focus has been set at about 4 to 5cm from the bottom of the box to allow for nesting material and the height of the birds. This should allow a good view of the nest, eggs and chicks.

The camera can take pictures down to 0.05 lux (which is fairly dark) but on dull days it struggles a little. Lights have therefore been added to assist the camera, and we have used a couple of spare low voltage decking lights left over from another project. One light is sufficient, and the other is just a backup incase of failure.

The birds don't mind the light, but we wouldn't leave it on all night. It is connected to a timer which will need adjusting as the days get longer and we move into British Summer Time.

The box also contains a small microphone, which can be seen uppermost in the picture below:

One other important item was to fix a metal plate to the front of the hole. This will stop Woodpeckers and the like from enlarging it and getting to the eggs or chicks. We nearly suffered badly from a Woodpecker last year, so best to be safe!

Nest Box Black and White Camera
The internal mono camera is the same one that was used as the main camera last year. It's a Pro-240 black and white camera with six LEDs for infra-red night vision and audio capability from Henry's Electronics in London (model now superceded). They say it is ideal for bird boxes, which it is, but you do have to adjust the focus yourself once it is installed. This means getting out the screwdriver set and removing the electronics inside. Once inside you find a tiny screw that allows you to rotate the lens for focusing.

If you do this yourself (with any fixed focus camera), just remember to set the focus about 4 to 5cm from the bottom of the box to allow for nesting material and the height of the birds. That way you should get a good view of the nest, eggs and chicks. The other thing to watch out for is the LEDs, they can be too bright. We found that at night all we could see was a white 'halo' at the bottom of the box. Clearly they were too powerful, so we blanked out four of them with black tape and diffused the remaining two with slightly opaque plastic.

In normal light conditions, the LEDs are off because there is enough light to register an image. Once it starts to become dark they switch-on and effectively make their own light. Only the camera sees this and not the birds.

Pro-240 Camera

The camera has three connectors on the end. One for a 12v DC power supply, one for video and the other for audio. These cables were extended using RG59 coax cable for the video, and standard speaker wire for the audio. The cables are then plugged directly into the back of a computer.

External Colour Camera
The camera that monitors the outside of the box is another CCTV camera, much the same as the one inside the box. It gives a good picture at 625 lines, but only works down to 0.8 lux.

The camera has been placed inside an old exterior CCTV housing to keep the weather out.

Computer Hardware
We use two 1.3Ghz Dell Dimension 8100 tower PCs running Windows XP Professional installed with 1gb ram and 75gb hard discs.

The video cables from each camera are plugged directly into a DVR (Digital Video Recorder) card located inside the PC, with the audio cable being plugged into the sound card. (A DVR card turns your computer into a digital photo recorder without the expense of using VCRs etc.).

DVR Card

Computer Software
The DVR cards came with their own image capture software, but it wasn't really up to the job. After a bit of searching and testing, we settled on Active WebCam.

The software is set up to detect any motion that a camera might record, and when it does, a movie file is recorded to disc. Given that we are not around all the time, it is far easier to review movie files than a folder full of still images.

This is how we see the two cameras on the computer screens

Active WebCam is quite reliable, but a bit of a memory hog and can crash on the odd occasion. The way round this is to automatically restart the computers twice a day. Thankfully they include this feature in the software, so it really does look after itself.

The web site is authored and maintained using Macromedia Dreamweaver MX. Miscellaneous pictures are taken with Canon digital cameras (A40 and EOS 350D) and are processed for the Web Site using Adobe PhotoShop CS.

The graphs are put together in Microsoft Excel and exported into PhotoShop CS before being used as jpeg images within the site.

WebCam
Every 8 seconds Active WebCam takes a snapshot and uploads it to the Web Server via our broadband line. The WebCam page refreshes every 10 seconds. By uploading a new picture every 8 seconds we hopefully eliminate the possibility of a viewer seeing the same picture twice or seeing a blank screen.

Weather Station
The data that we enter into the weather graphs is recorded on a weather station inside the house. It has a remote sensor which is located outside. Each morning the unit is polled for the previous days' readings and then reset.

It would be great if the station plugged directly into a computer and automatically wrote the readings to disc, but those sort of systems are still very expensive.

Master unit inside the house

External sensor outside

Listening Device
The Orbitor can capture distant sounds from up to 300 feet away and it has a viewfinder with a 10x zoom to assist in pointing it at the right object.

Difficult sounds sometimes impossible for the human ear to pick up appear to be only a couple of feet away. If you walk along at the same time as using it, it is amazing how loud your feet sound, let alone how they must sound to animals with better hearing than humans.

The sound quality is extremely good, it has headphones, a volume control and it can record up to 12 seconds of sound onto a digital chip inside.

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