To all swiftlets landlords and future landlords,
I have been in the pest control industry for some years previously and will soon join the amazing swiftlet farming. I hope you will find these suggestions helpful to your swiftlet BH in terms of gecko or lizard prevention or problem. I have read that they might gulp down swiftlet eggs and even young chicks.
If you are already operating, try getting rid of them manually first. If you haven't invited swiftlets to be your tenants, you can try the following to discourage geckos from occupying inside before you implement one of my suggestions.
I know that gecko is quite sensitive to insecticide from the pyrethroid family (a.i. e.g., deltamethrin, cypermethrin, most household mosquitoes repellent spray containing them) but I am not very sure whether birds would be affected by it. There are also health care and agriculture grades available in the market. Normally, the health care grade pesticide is more durable. So, try not to do it if inside your BH already got birds.
Teflon (non stick) coatings. Applied teflon coatings onto a portion of the building wall perimeter at the height above the door, may be at 6 inches wide. Or you might even applied to customized aluminium or fibreglass sheet first and the fastened them to the wall later. For further info, check out http://en.wikipedia.org/wiki/Polytetrafluoroethylene & http://en.wikipedia.org/wiki/Gecko
Custom made a device to contain water and with attached roof (to prevent rain from causing the detergent container to overflow) and continuously wrapping it around the perimeter of the building at the desired height. Fill it with diluted detergent. The detergent will cause the gecko to loose its weak Van Der Waals sticking forces. It will either drop back into the container or THE GROUND. Please experiment it yourself before you really implement the suggestion. Find a plastic bucket, add diluted detergent about half an inch deep, catch a live house lizard or gecko and gently put it into the bucket. Please try not to drown the gecko.
Please refers pictures below: