Getting rid of birds in your attic is not as difficult or complicated as it may seem. Assuming you're dealing with run of the mill small birds like pigeons, jays, or shrews as opposed to something more aggressive like a hawk or an owl, the solution can be as simple as just trapping and removing them or just closing up holes in the exterior of your house.
It's important to remove attic-dwelling birds as soon as possible, as they're not only loud and messy, but their droppings carry diseases like Candidiasis and Histoplasmosis which are harmful to human health.
Step 1 - Determine How the Birds Got There
Finding unwelcome birds in your attic is actually a common problem across the country. What many people take for granted is that while you are protective of your house, in order to build and construct a home on that same plot of land, a bird's home and habitat was destroyed. Therefore, that same bird stays on your property for the familiarity.
Alternatively, a bird trespassing may be a simple crime of opportunity. Open cracks or broken windowpanes on the outside of the house provide a welcome entry point for the birds.
Step 2 - Trapping and Removal
If there currently aren't any birds present, but you want to keep them out proceed to the next step. If there are still birds presently in your attic, you will need to safely trap them and then remove them. Avoid poisons or lethal traps. Birds indoors are pests, but they are very easy to handle in a humane way.
Simply fill a bowl with birdseed and place it in an open spot inside the attic. Wait for the birds to come to the bowl and finish the seed. Now, refill the bowl with more seed but place the bowl inside of a cage trap. When the birds venture toward the familiar bowl seeking the birdseed, the cage trap will catch them, at which point you can carry them outside.
If you do not have a cage trap, when the bird ventures toward the bowl of seed, you can throw a towel over them. You can then quickly wrap the towel around the bird and carry it outside where you can release it.
Step 3 - Close Off Entrances
If your home has a crack or a broken window, repairs are in order. Birds aside, it's probably a good idea to close up any holes in your house. If the birds are flying in through an intentional opening like an attic's viewing window, chicken mesh, also known as chicken wire, can be stapled in place.
The wire will maintain visibility and air flow but will create enough of a barrier to keep birds out.
Step 4 - Prevention
Even outside of the attic, bird feces is diseased and unsightly in areas like your roof or yard. To expand your bird-proofing outward consider using spikes and other barriers on your roofs and property to deter them even further.