I did some math

Based off of averages and theory, I deducted that a flock of 100 sparrows consisting of an average 60% females can reproduce an average of 1400 birds in two years. That number is reduced by 30 for every female that you trap.
What this means is you need to trap 47 birds in two years in order to maintain control of one single flock of sparrows.

This seems like a small amount doesn't it? It sure is motivating to me, especialy if you have a repeater. Now another thing to remember is that there are rarely 100 birds in a single flock as this tends to happen more at agricultural sites and hardware stores than at your home, so control is quite possible and within reach.

Just remember to trap year round to ge the strangers every once in a while and you should be on top of your population soon!

Holy cow that's alot of sparrows. You're right though that doesn't seem to be alot of sparrows that you would have to trap.

so what would be considered an agricultural area? I live in the country, with single homes spread out across the entire property of 320 acres.

Generally anywhere farming occurs. The reasoning behind the larger numbers in these areas is that the HOSPs feed on the spilled grain from the harvesting process as well as around silos and other storing methods.

Since you're rural if there aren't any of these agricultural sites in your area you should generally see fewer numbers of sparrows than in urban areas even, mostly due to a larger concentration of feeders and food waste improperly discarded.

Of course that's just statistics, have you seen large flocks around your home?

I have none around my home (knock on wood). I do all my trapping at work and at friend's homes. I did have a male HOSP at my house one day and he was gone the next...never seen him since and that was years ago... I pulled out the shotgun, but he was gone by the time I went out in the front yard. Too many bluebirds here to put at risk. You can not drive down the road without seeing at least 5-10 bluebirds on the wires.

Looks like the statistics hold up there, you are a lucky man indeed. It's awesome that you help others even though you don't have them at your home, quite admirable.