I am sure you had taken advice from friends or those who you think that are real Sifu by installing gadgets on the entrance- hole hopping Owls won’t enter your Bh. The truth is most techniques that applied by most don’t work. It is more of a Myth to make you feel good rather than to prevent Owls from entering.
The Myth of preventing Owls from entering Bh (which doesn’t work)
1) Installing florescent light at entrance hole (Owl get immune and use to it.)
2) Spot lights( the strong spot light affect the visual of Swiftlets and cause seconds of blind which can be fatal and this make praying easy for Owls.
3) Bars or wires in-between Entrance hole (It kills birds because with the sheer speed of more than 100k/h diving into the hole during home coming the birds may bang on the bars.
4) Smaller entrance hole (Not good for new Bhs)
5) Electric wire (need maintenance and it only works on high voltage, low voltage with step-down is ineffective.)
6) Mouse traps (often it kills more Birds than Owls)
7) Fishing netting (the same may kill birds too.
8) Many more…..
The best see above pictures. It works….. Not easy to get those traps here. Catch and release them in other places.
Good Swiftlet farming All!