Livezey KB (2010). "Killing barred owls to help spotted owls II: implications for many other range-expanding species". Northwestern Naturalist. 91 (3): 251–270. doi:10.1898/NWN09-38.1. JSTOR40983223. S2CID85425945.
Courtney, Stephen P.; Blakesley, Jennifer A.; Bigley, Richard E.; Cody, Martin L.; Dumbacher, Jack P.; Fleischer, Robert C.; Franklin, Alan B.; Franklin, Jerry F.; Gutiérrez, Rocky J.; Marzluff, John M. & Sztukowski, Lisa (September 2004). Scientific Evaluation of the Status of the Northern Spotted Owl(PDF) (Report). Portland, Oregon: Sustainable Ecosystems Institute.
Livezey KB (2010). "Killing barred owls to help spotted owls II: implications for many other range-expanding species". Northwestern Naturalist. 91 (3): 251–270. doi:10.1898/NWN09-38.1. JSTOR40983223. S2CID85425945.
Livezey KB (2010). "Killing barred owls to help spotted owls II: implications for many other range-expanding species". Northwestern Naturalist. 91 (3): 251–270. doi:10.1898/NWN09-38.1. JSTOR40983223. S2CID85425945.