I’ve made the one in the previous post as well as this one.
http://www.chuckspurplemartinpage.com/spartrap.htm
I’m in town and don’t have a ton of sparrows, but they have taken over swallow houses in my yard. This one is more nesting driven as you will see. I would think for larger numbers and more year round use the previous would be better, but just my opinion. I suspect proper “tuning” for weight of the bird is key. I’ve released swallows and chickadees, so important to be around if the trap is out. I grew up on a grain farm and I remember having a funnel style trap on top of a grain dryer that sometimes had 1/2 dozen or more at a time.