Do not discard away the empty bottles of Love Potion after using them. It can be use to prevent accident by placing them about 2-3 ft from the inter hole forming a barricade. It is invaluable, it may save your live.
The barricade of bottles stops us from the deep fall into the inter hole shown on the pictures below. There are already a few cases where people mistakenly took a fall into the inter hole and die.
( 2-3 ft from the Inter hole)
Before placing the bottles at the inter hole, file each bottle with 1/3 of water. This should be good enough to hold them standing. When we kick and knock over some of the bottles accidentally. The bottles will fall into the inter hole making a thumping a sound (due to weight in the bottles) indicating that the edge of the inter hole is in close proximity.
( Keep the Love Potion Empty bottles for good use)
I have seen iron railings, ropes, wires, even a 1-2 ft high cemented walls being used as barriers at the inter hole for safety reasons but all these would restrict the swiftlets from maneuvering and flying freely to the lower floor.
Scientifically proven, any poles or objects smaller than 2 cm cannot be detected by the swiftlets echolocation clicks. With this limitation, swiftlets might smash on to them
( This is how it should look)
It would be suggestive to place something bigger. I have written some proposition about placing bricks around the inter hole but If you have stacks of Love Potion bottles, use them.
Love Potion helps to increase bird population and Nests. Its bottles are also an accident resistant tool.
Good Swiftlet farming All!