I’ve been interested in getting a caged feeder similar to this one, as most of my feeding is done in the trees. I was reading some online reviews and a few people wrote in that when something spooked the birds they returned to find dead birds in the bottom of the cage. Almost like the song birds were so spooked that they hit their heads on the cage and died. Is this true? I see so many on the market that I find it hard to believe so many would sell if this were a possible threat.