Animals are very opportunistic creatures - we'll call this Ornithology 101 - If You Hole It They Will Come.
Ornithology, from the Greek word ornis, meaning "bird."
Birdhouses large and small only need a hole to attract birds. And when you build a little house to go outdoors for birds, if you hole it they will come.
What happens when you leave holes in houses large enough that birds can get in?
They will come!
Gable townhouse roofs often have an architectural detail on the front of the house - another gable roof, almost a huge dormer.
This townhouse has such a detail. It's a nice addition to the house design.
However this house has something else - large holes were left on each side where the edges of the front gable roof meet the main roof on the townhouse.
And inside each hole? A condo community!
I watched the comings and goings for a while. There were a lot of birds there! And this was a busy day. There was a lot of bird work to do.
Well, it was the first day of spring. Spring brings lots of bird work to do. Nests, you know.
Here I am parked for five minutes, looking at the front of the house. And I see bird activity that is abundant, frequent and in great numbers.
Nobody has noticed this before? This house is 18 years old!
My recommendation: houses can be lived in by more than people! Once I saw a large hole in a house and inside the attic was a nest made of hay, and large enough for your average ostrich! Who knows what was living there. All a bat needs to get inside is 1/4"! And if they find that size gap, and they will, bats will move in. Bats come in large numbers too! Look at the holes in some bird nests - they are no larger than 1" in diameter. If you leave that size gap on any house the birds will find it, they will come, and you will experience Ornithology 101 too! Your house will be the largest birdhouse in the neighborhood. I wonder if the birds have their own HOA?
Jay Markanich Real Estate Inspections, LLC 
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560
Good morning, Jay. There are a lot of diseases associated with birds and their droppings.
Yep. Once I opened an attic door to more bats that I had ever seen in my life Michael. The guano on the floor was inches thick. I asked the renters if they were sick a lot and the mother said they were always sick. That homeowner was opened up to biggie problems with my inspection!
OH MY
do we see a law suit in the future? If the owner was unaware of a problem are they still liable?
Yes, and where there are birds, there is bird doo, too.
Liable for what? They are living there and so are the birds James! My clients are going to want those holes sealed up, however!
You can see the stains outside because they don't do that inside where the nests are Debbie. Bats do! And bat doo is very dangerous.
Good morning, Jay....once you get those visitors in your attic space, good luck getting them to leave!!
They might during the day, briefly, but not if there are eggs Barbara. Closing off the holes is the only solution, unfortunately.
Hi Jay,
I was at a home last month that had a hole in the soffit. I got close to the hole and a bird flew out and scared the dickens out of me. LOL
Never leave these holes in an un repaired contition. Birds are smart they will make use of these voids.
Have a good day in Bristow.
Best, Clint McKie
Jay I'm pretty sure I have a bird nest in my attic, but it doesn't bother me. Except when I want to sleep in and all I hear is the "cheap cheap cheap" of baby birds.
Good morning Jay,
Everything is going to the "birds" today.
Make yourself a great day.
They don't like it if you get too close to their bubble, Clint!
Once there they will never leave Suzanne. This house had many, many.
Well, Raymond, better than a lot of animals I can think of!
Jay, all too often our homes are "for the birds"
Mr. Hitchcock would be proud of this house, Charlie.
You are so right about these bird housing projects Jay. We have to think of these things ahead of time to prevent the bird infestation.
Tom - those two holes are much too big not to expect birds in there. At least the tigers won't get into that house.