Considering that they both like to birdwatch, he might re-think letting the trapper remove some coon, 'possum, etc. Doing so will take some pressure off of the nesting birds. It'll be a constant battle; it's amazing how fast Mothere Nature fills a void. It's always a balancing act between predators, prey and the available space/resources for them.
We haven't even mentioned feral cats yet, have we?
