new to martins

[Boardman Birder]

last fall i built and put up a classic 16 compartment martin house.
last week a pair(?) of martins found my bird house and now there are 3 hanging around, 2 males and apparently a female, quite frankly i hadn't expected to have birds the first year.
going by internet advise i had closed off the holes on the north and east sides and have left open only 3 holes on each side facing west and south.
if i am getting this much attention from the birds already should i open holes on the other sides or let them crowd in as it is now?

[flyin-lowe]

In the northern range of the US it is not unheard of to attract martins right after putting up a house but it is not the norm. If you are 100% certain they are martins then it would not hurt to open up a few more cavities. If you start to see sparrows or starlings trying to move in you could close off those cavities. Many years ago what I thought was my first pair of martins ended up being tree swallows.