Dead birds and sick trees???

Ok, so I have had 3 crows drop dead out of my trees in my front lawn, and I'm worried. They have each been reported, but the west nile testing have not been able to come out and do so...so I'm stuck. I just got off the phone with the West Nile Virus Hotline and again, they can't do anything. So my question is, who do I get a hold of to come check out my trees? It's obviously something going on in the trees because my lawn is the only one with a dead bird! How Scary! Any and all help would be MUCH appreciated.