Everything we do to change the balance of nature can have far-reaching negative effects that we may not ever be aware of. Birds are being affected by decreased insect populations depriving them of their food.
There’s no such thing as a spray that kills only one kind of bug. “Cide” means kill…insecticide, pesticide, fungicide, herbicide, etc. I urge you to read Mary Reid’s article. The for-profit companies that provide the mosquito spraying service should not be the only source in vetting the safety of the chemicals used.