Re: Swarm Trap Finished
I have built similar TBH swarm traps. However, I built them as dual purpose nuc/trap. For nuc purposes I cut a slot in the back to be able to insert a boardman style jar feeder into. This slot is about 2" up from the bottom of the box.
My boxes have the top of the ends flush with the sides. You can see pictures on Michael Bush's site of his TBH's that are similar. For trap purposes, I close up the top entirely with bars, and allow the feeder slot in the end to serve as an entrance. For nuc use, I will plug the front slot either with a feeder, or a plug built to fit, and adjust the bar locations to allow a top entrance.
I don't have a link available right now, but I have seen studies that suggest a lower entrance is preferable to a swarm, compared to a top entrance. Also, I have seen some reports that the most attractive entrance is about 5 square inches, although I admit that my slots are about 3+ square inches. My concern with the dual top entrance pictured is that two holes might be considered less defensible than one. And I just put 4 drops of LGO directly onto the wood, inside the trap.
Of course, swarms sometimes move into the most unlikely spaces, defying all predictions as to what might be optimum.
This is my first year, I have 5 traps placed, and have caught one swarm so far.
USDA Zone 7a - elevation 1400 ft