Steve: The House Sparrow vs bluebird comparison is a no-brainier, as HOSP aggressively compete with bluebirds for nesting cavities. According to the link in the original post, ECDO were not thought to be negatively affecting native species. That article was from 2014, so things may have changed since. Curiously, Kathi Sent from iVan II, my iPhone ______________________________________________________________________ Ohio-birds mailing list, a service of the Ohio Ornithological Society. Please consider joining our Society, at www.ohiobirds.org/site/membership.php. Our thanks to Miami University for hosting this mailing list. You can join or leave the list, or change your options, at: listserv.miamioh.edu/scripts/wa.exe?LIST=OHIO-BIRDS Send questions or comments about the list to: [log in to unmask]