Is it your first house/year?

There are many reason's,..wait and see.
I wouldn't touch it, make adjustments when they leave.
Perhaps too close to trees buildings etc. perhaps
size or surroundings not suitable, water source etc.
My first martins last year were in and started to build a
nest but left soon after, ...most possible reason for this,
the size is too small, I'm going to enlarge it.

Do you have a good guard on the pole? Could you lower the housing and see if something like a snake could have gotten in?

Thanks for the responses. It's an established house, no location issues at all. It's been full every year. That's why I say the returning Martin's wouldn't land.
Good suggestion re snake. But we do have a snake deterrent wrap around the bottom of the pole.
I watched for awhile yesterday. It seems some other type of bird has taken over a couple of the nests. Looks like bluebirds. What a quandary! Some of the Martins have been stubborn enough to settle back in some of the empty nests.
Wondering if I hurry up and get up another house will the displaced birds adopt it?

You could put up some housing for the Bluebirds nearby. What you're saying is you have an established colony. The Martins will win out over the Bluebirds in that case.

I took my house down today and checked it out, two nest were
kind of half finished, one had a egg in it [from last year].
The inside size dimensions were 6x6x6 inch high.
According to a website these are the min. required size.
With the boards I could easyely buy, then went ahead and build it like this.
Now I modified it easily and basically is
double the size, 6x12x6 inch high...will see.
The 14 story is cut to 7 story, good enough for a start.
I would have liked a 7x12 inch floor size, hope 1 inch narrower should still be acceptable.
They say lager is better, ..it gives them more protection against predators.

I figured when first building this and a smaller size would be working for
me it would be a warmer house for our colder area,
known that birds/eggs can get chilled.

This what it looked like, ..nest disturbed from taking down.
Can you tell by looking at this why birds left?

@ Konrad: Best of luck on getting the Martins to hang around. They are such an asset to the farm and garden. Especially this year with the mosquitoes and all other things buggy being so bad.

Thanks..wish me luck.
You're a experienced Martin birder....I have lots to learn yet. Have many tree swallows getting the bugs but at the peak of the season or when humidity is high, there are "SWARMS" of mosquitoes, a army of birds could hardly make a impact.

What is your inside size of the nest box? How many pairs do you get?

Here I found a picture with the house on the very left.
{{gwi:108309}}

What happened to the apples on the lower part of the tree? Looks like it may have been the same thing that happens to the cherries on the lower part of my cherry tree. The birds get the ones on the upper part and if I'm lucky I get a handful.

It is very difficult to tell from that photo, but it appears there is no protective baffle on it? That picture of the nest definitely looks disturbed. Perhaps a squirrel or raccoon climbed up there? You may have a good baffle and a way to lower the housing that are just not visible in that photo, so these are just thoughts. Most Purple Martin landlords also use netting to trap any snakes that try to climb the pole.

Thank you all!
Said above that the nest was disturbed when I took down the house.

I talked to a local experienced martin birder and hes says squirrels an snakes are not a issue here, we have no climbing snakes, and the odd squirrels we have are more in the bush, I might see one in a year, they avoid open area,..if it was them, then the egg would be eaten I would imagine.
Owl's and hawks is the main concern, heaving the house larger then you find in most plans on internet is the key, it will prevent hawks and owls from reaching in and grabbing the young. Keeping the house at least 40 or 50 feet away from trees. I have small trees near by, the house is higher then the trees, I can move it to a more open area. They like more martins around as their neighbor.
They also like people around, [hardly any].... helps keep predators away.
Getting them started and feel save can be challenging.

Time will tell.

Bob, yes....mother deer took down the apples on the lower branch for Bambi.

Just to close out my initial thread......... I put up another Martin house and had hardly walked away before the happy Martins were arguing over who gets to move into the new condo. :> So, now there's enough room for the Bluebirds and the Martins.

windyoaks's

>>What is your inside size of the nest box? How many pairs do you get?