The trap works very well on sparrows. Mind you, may have to wait several days or change locations- the first couple days it did not catch any. Then finally, got a few.... moved to a different location and WHOA........ in just one day there must have been 25-30. WAY more than I thought were in my area.... Next day in same location caught 15. Used chicken feed as bait.
Another time I noticed the next door neighbor had a bird feeder and used the standard bird seed mix, and it was mostly sparrows visiting it. So I put out the trap again with bird seed as bait.. that again got tons sparrows but also some native birds(white crown sparrows, a towhee and house finches). Of course let the natives go.. as they are not the problem birds going in my coops. btw despite the neighbor having a bird feeder, sparrows were still forcing their way into the coops in large numbers, daily.
A possible con for some is having to kill them. They(house sparrows) REALLY should be killed NOT "released somewhere else".
p.s. it seems to help a lot if you leave one or two sparrows in the trap. Put in a bowl of food and water for the bait birds.