Beside the entrance design, there are a lot of small little things that done by the consultant which I believe a very important factor for the BH Success. For Example, Vent hole design. He did not use PCV pipe. He also cleverly make use of internal light to extract birds and use ventilation fan with timer to control the BH ventilation.
I also checked some other BH done by the consultant. Among them are my wife's cousin BH. I called him to find out more about his BH and the consultant. He told me that after 1 year, the nests already reach 60 to 80 nests. Consider the location is still not the prime area, I think the results are very good.
After all those studies, I decided to let him convert my old BH ground floor to BH and also revamp my old BH on upper floor. For those who interested to find out more, you can either call or email me. 02-91275446 or firstname.lastname@example.org