David, just tap in the above to Google and you'll get chapter and verse. It doesn't kill them fortunately, but is obviously disadvantageous. Cleaning of the feeding stations is recommended.
Was surprised to hear a large gull flock calling overhead today but couldn't see them in the low cloud. I suspect its the Black headeds returning to the bog as I saw 44+/- on Pant pit earlier in the week together with a Little Egret.
My reed buntings are loathe to leave the feeders as are 5 blackbirds all first year males.