You can choose either the monkey house type or the top entry type.
If you choose the monkey house type you need to opt for side entrance and not opening the monkey house roof ( a combination of Monkey House and Top Entry).
A very common mistake and will eventually lead to much lesser birds occupying your BH.
I was visiting this BH in Papar, Sabah in August 2013 and saw the exact same mistake.
The owner was not very familiar about this but I explained to him a long list of my reasons why.
I stressed to him that I have accoutered this type of BHs before and once they followed my advise those birds started to enter.
"So what should I do now Pak Harry" he begin to ask for the right solution.
Well what he should do was to cut of the rectangular shape and turned in into a slanted structure.
Let me show you what I sketched for him.
This was how his current entrance area looks like.
He is using a rectangular box about 6 feet height and the birds have to enter from the top roof opening.
My main observation when you use this type of entrance hole is that those new birds will find it very difficult to locate the top opening areas.
They will circled around the box searching for the entrance area and once they could not find it they will dash away and you loose a golden opportunity.
This was what I suggested him to do:
He might think that I am wrong but trust me I have done this before and the new shape designed is much better with bigger entrance size.
If you use the original method you will make those young birds to circle the monkey house to find the entrance hole.
If they could not find the hole they will soon run away for some other better things to do.
If you changed or adopt the one I proposed those young birds once reaches the lower part of the wall will be able to find the entrance hole and will quickly enter your BH.
I have also sketched where to install the hexagonal tweeter plus two kite tweeters beside it.
Try this method and I assure you that your BH will get more visitors inside.
All these are from my very long experiences plus site observation.
Trust me with this and you will not loose anything except more birds will populate your BH.
Call my number or write to me if you need more information
My telephone number is +60177551318 or email to firstname.lastname@example.org