CCTV in BH is a must.

Finally after almost three months, I got my telephone and internet line.
Now everyday I can watch birds on line in my bird house which situated 600 km. from where I live.
I can watch from a computer that I can also reset all the parameters from my house.
I can search and replay all the recorded clips that we pre-programmed to the DVR.
I can count exactly how many birds stay in my bird house now.

If you have a mobile phone, you can also download program for free and watch your BH from mobile phone, anytime, any where that you have an edge or wifi signal.

More than that, we can observe how birds react to each type of speaker we installed, how birds react to different sounds we changed. Also we can see that at particular spot, there is only one bird, after few days/weeks, he bring in his partner, then we see some rate X action and later they build their nest.

We can see whether it rain or shine, we can see the light and wind direction in different season.
We can see predators, I saw a big lizard yesterday on the wall.
We can see the micro conditions of each floor from a humidity-temperature controller.
We can see at what time they come back, at what time they wake up.

Enough reasons to convince you all to install one? If not, there are more:

Every day I watch three BHs in action, the other two belong to my friends.
Three BHs are on different locations, I can see how the weather effects the number of birds played around the bird house. Yesterday and a few days earlier, my BH on the East coast was very dried and quiet, while my friend's BH on the West coast rained and had soooooo many birds played inside his BH.
Then, I heard about the Tsunami, we said jokingly, no wonder all birds with their natural instinct were hiding in the West coast.
In the afternoon, we had few minutes rain, then in the evening, birds came out of nowhere!
We can alert each other if we see something wrong, for example, light's out, amplifier doesn't work, temp is too high,etc.

More than enough reason now?