Sorry to hear about your troubles. That would bother me quite a bit too. After the first bird I'd be thinking it was a predator but the second case doesn't sound like a 4-legged predator or raptor at all so I'd lean toward the kid. I wouldn't blame him or talk to him or anything yet until you know for sure, and to find out I plant a game cam and do what you're doing by keeping a really close eye on the birds. Just my two cents but if you do find out it's him I wouldn't try to reason with him since any sign of weakness on your part would probably just encourage him all the more. If you're comfortable confronting him, again with evidence, I'd try that first and light into him really good. If not you could of course call the law. Unfortunately with people like that, the only thing they fear is a good whoopin' and most other measures won't have any effect or will make things worse. Only when the cost to them outweighs the fun they're having do they seem to find something else to focus their attention on. In any event I wouldn't point the finger at him until you're 100% positive he's the culprit. I seriously feel for ya though because a situation like that will have you fuming and worrying all day.