I am sure for new comers who are new in Swiftlet farming would wonder why there is a light fixed at the entrance hole.
There would be guessing game here, as to why the entrance needs a light, "Is it for the Swiftlet to see"?
Well, the reason being is to scarce off Owls. The light is fixed at the entrances which controlled by a timer. This is to prevent Owls from coming near the entrance and to prevent them to enter the farm. As most Owls are active during night time especially the time the sky is getting dark.
But bare in mind that not all Owls catch their prey at night there are few species that actually active and catch their preys during the day time which I had witnessed myself.
Initially when the light is fixed at the entrance this would scare off Owls but over the time the Owls might get adapted to such situation as most animals are able in adaptation to survive in the animal kingdom.
Besides that having light at entrance attracts insect thus this would at the same time attract swiftlet to feed. With plenty of insect around the entrance hole chances are some swiftlet may go in to the farm and stay over night.
With plentiful of insect during the night when all Swiftlets had settled down in the farm this would be the hunting ground for small Bats. This would expose your farm to Bats and they might stay in your farm considering that there are plenty of foods at your farm's entrance.
Other perceptions are as a guide or a target land mark for easy identification for young Swiftlets therefore sometime you may see some entrances are fixed with light of different colors.
There are always advantages & disadvantages here......so you decide.