You will need:
- 2 x two litre ‘pop’ bottles with straight sides
- 2.272 litre (4 pint) milk container
- thick plastic garden wire or wooden ‘kebab’ type skewers or stiff metal rods
- pointed scissors.
Cut the top off bottle 1 leaving about 25 cm of the bottom part as the capture chamber. It’s best to draw a line around the bottle otherwise you might end with a spiral!
In the remaining top part (the funnel) make several 5.5 mm holes around the shoulder of it. It is not easy to drill such flexible plastic but melting it with a soldering iron or heated drill end or metal rod is easy and this leaves a smooth sided hole. Practice on a similar bottle to get these holes the correct size.
In the bottom of the 25 cm long capture chamber make a lot of small holes using a small heated drill or needle. These holes will let the vapour of the ‘bait’ up from the bait chamber into the capture chamber above it.
The funnel (the cut off top) with its 5.5 mm holes, but without its screw top, is placed upside down into the capture chamber and secured in place with stout plastic garden wire or a thin metal or wooden rod (Kebab stick?). In the past I have used plastic covered garden wire but then turned to rods as they make construction and hanging easier. A heated metal rod can used to make a hole through the junction of the funnel and capture chamber. A rod (wooden or metal) or wire passed through this joint will hold the two parts together. Make the rod or wire couple of centimetres wider than the bottle as then the roof and suspending wire can be easily attached.
Using another plastic bottle (bottle 2) of the same size and with straight sides cut off the lower portion to about 18 cm long. Too short and you may not be able to get your bait tin in. This part will accommodate a clean empty can of the baked bean size which will hold the hornet bait. After the bait chamber and capture chamber have been pressed together they can also be attached with a rod at the joint in the same way as described above for the capture chamber and funnel. Stout plastic covered garden type wire can be used instead of rods but it can be fiddly getting it across the inside of the bottle and into the holes opposite.
The top of the trap is still open and a roof needs constructing to stop rain getting in and to guide any hornets into the funnel of the trap. The easiest way I have found to do this is by cutting up a 2 litre milk carton. The side opposite to the handle seems to give the deepest roof sides and a reasonably sized entrance. It is thought that a black roof is better in guiding hornets in and in this case the plastic roof can be painted though other already black materials can be used. Indeed the colour of the whole trap is an intriguing though unresolved question.