We have a lot of swallows (mostly barn and green) on our rural property. Wife is currently battling a pair that wants to build a nest above the back door. Anyway... In the evenings and mornings there might be one dozen or more contstantly flying around between our trees eating insects. Somewhat mesmerizing to watch. Gemini says a single swallow eats about 850 insects per day. Pretty sure that includes a high percentage of mozzies and flies. 850 x 12 = 10,200. Let's assume 50% mozzies (we have lots). So 5,100 fewer per day. Go swallows Go.

Reminds me of a story I read about an overpass in Texas that housed tons of bats. It creeped some folks out, so they disallowed them to roost. Once the bats were gone, the neighborhood was overrun with insects. Did not take long to have the humans get the bats back. Go bats go.