If I put bleach in my fountain to kill mosquitos will it harm the bird

Yes. use mosquito dunks

If the fountain has circulation throughout the mosquitoes shouldn't be able to breed in that water. They normally use quiet stagnant water. Any chemical added to the water may affect the birds as it happens in nature by affecting their fertility or thin fragile eggs. Look what happened to birds in the past from chemicals that got into their feed and water from the chemicals we were using then. Check with a local trusted greenhouse, not a big box store, they will be able to give you suggestions that will not harm your birds. If they say bleach is ok, they will be able to help you figure out how much to use.

I would't do it! Clean water daily & there shouldn't be a problem.

Do NOT put bleach (even a teaspoon) in your fountain, unless you want to kill birds, or cause them to have severe problems with having eggs with shells so thin or malformed, that their baby birds die prior to hatching. WOULD YOU DRINK A GLASS OF WATER WITH EVEN A TEASPOON OF BLEACH IN IT?!

Birdbaths and other small areas around your landscape can also be treated with bacterial insecticides, which are available at most garden centers. These products are available as donuts, dunks or granules and usually contain the bacterium Bacillus thuringiensis israelensis, which kills mosquitoes but is not harmful to birds, fish or other wildlife. Dunks are ideal for birdbaths and can control mosquitoes for up to 30 days.

Yes

It will kill the birds too.

Use a mosquito dunk. They kill the larvae and will not harm birds at all.

Mosquito dunks can be found at all your big box hardware stores.

yes

all you need to prevent mosquitoes is moving water. Even a small, inexpensive solar fountain will stop them from breeding in your bird bath. Birds will still come to bathe.

I wouldn't worry about mosquito larvae in my bird bath. The birds will probably eat them. And you really should be changing the bird bath water every three days or so, long before the larvae will become a problem.

Agreement with the above - mosquito dunks and regular changing of water to interrupt the larvae hatching cycle. More info here: https://www.hometalk.com/diy/outdoor/pest-repeller/how-to-keep-mosquitoes-away-44423909

Go with the mosquito dunks, they are safe for birds.

Hello Suzanne: Yes, it is bad for birds, so don't do that :) You can get the dunks, or put in a solar fountain made just for bird baths. Mosquitoes don't lay eggs or hatch in moving water. That's why you see so many large fountains in ponds :) They make them just for birdbaths and you can buy them here: mini solar fountain - Walmart.com or here: Amazon.com : bird bath solar fountain and you can see some here: The Best Solar Birdbath Fountains, Tested & Reviewed - Bob Vila

YES!

Yes. If you have a way to keep the water moving with something like a fountain, maybe a solar fountain although those only run during the day, that will help.

Bleach and birds should not mix! The bleach is harmful to both mosquitoes and birds so use products that are harmful to mosquitoes and not to birds.

I use white vinegar in my fountain and the birds have not been bothered by it. I have blue birds that like to go under my patio cover.

Yes it will, I would go with the mosquito tablets….sorry but I don’t know what they are called.