Ovenbirds and chipmunks have a negative relationship (chipmunks raid the nests of ground nesting birds) and it's known that ovenbirds avoid nesting in woods with a lot of chipmunks. Any habitat or ecosystem changes (e.g. loss of predators, increase in food, etc.) that might favor chipmunk populations could push Ovenbirds off to more suitable habitats. Google "ovenbird chipmunk" and maybe throw in "nest" for more information. Good birding, Paul Hurtado -- Paul J. Hurtado Postdoctoral Fellow, The Ohio State University Mathematical Biosciences Institute, http://mbi.osu.edu/ Aquatic Ecology Laboratory, http://ael.osu.edu/ ______________________________________________________________________ Ohio-birds mailing list, a service of the Ohio Ornithological Society. Our thanks to Miami University for hosting this mailing list. Additional discussions can be found in our forums, at www.ohiobirds.org/forum/. You can join or leave the list, or change your options, at: http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS Send questions or comments about the list to: [log in to unmask]