Group standing around harp trap

Re-stringing Harp Traps – Evening Event

Un packing the two harp traps

So, what is a harp trap? 

Well, it is a metal frame, with vertical lines of fishing wire strung between the lower and upper poles, at about 1cm gaps. 

The idea being that if you set the trap up on a ride, or a gap between two trees, the fishing line will be too thin for the bat’s sonar to detect, and the bat will fly in to it, falling in to the fabric pocket at the bottom, unharmed. 

The bats can then be retrieved, processed (weighed, measures, ringed, radio tagged, depending on the mission); then released back in to the wild.

But as we know, fishing line stretches and breaks from time to time; therefore it has to be replaced. What better way to the required work, than at a social event, with tea, biscuits and good humour? 

Initially we all met upstairs at the museum, where Hazel handed out some leaflets on tying a blood knot (very important) and other information about harp traps. We then all traipsed downstairs to the hallway, to set the traps up.

Between Hazel and Mark and a couple of others with knowledge, we assembled the traps to see what needed doing. Quite a number of the end strings were fangled, some easier than others to unknot. Once done the traps were put up to full height, so we could see if strings were missing or lose. The traps were then laid on their side, the tension was slightly released and the stringing begun…
This is where the blood knot, generally used in fishing is so useful. You can loop the fishing line around the horizontal bar, tie the blood knot, then keep it tight under tension. This way, both ends can be tied. Bit fiddly at first, but by the end I think everyone had tied at least one or two.
PNG drawing of blood knot
Setting up the harp traps

By the time we finished the knotting and restringing it was about 9pm, time for home or the pub. 

The traps were disassembled, rolling the lines around the horizontal bars, so that when they are unwound at the start of the season in the field, they should all play nicely, like a musician’s harp – with no missing or lose strings. 

Well we can all hope anyway!

Share this post!

Leave a comment

Wordpress Social Share Plugin powered by Ultimatelysocial