The BoS greatly reduces two sources of hassle:
1. Installing bulky speakers near to a nest-box 5 metres from the ground and supplying mains power to the speaker power supply. The BoS uses a small Car Tweeter with a single piece of low voltage speaker cable to it.
2. An automated system driven by a conventional timer to play calls at chosen times, using a player not designed for this sort of thing. The BoS starts or stops playing when the power is switched on or off, and it comes complete with Swift calls.
So, in order to try to mitigate any disappointment, we suggest here an alternative which is fairly easy to put together yourself. This alternative solves 1, and to some extent 2.
Radioshack amplifier see here (prices seem to vary £10-15) This amplifier has its own speaker, but plugging a tweeter into its output socket switches the amplifier's own speaker off.
Short cable with 2 jacks between player and amplifier (<1£)
Long cable with 1 jack between tweeter and amplifier (~£4)
9 volt power supply (e.g. here) (say £5)
Putting this together yourself is quite straight forward.
To complete this system, you need to provide a player and 240 volt timer switch (or drive it manually). If the player is a solid state mp3 player, then it can be run 24/7 in repeat mode, with the amplifier power supply plugged into the timer. Otherwise, you will need to find a player where holding the play button down enables play/noplay with power on/off. Driving a player with rotating parts 24/7 does not do it much good (personal experience).
Lastly you can download Swift calls from the Dutch Swift Association
It is suggested that you use the .wav versions of
As well as the CD provided by Swift-Conservation