http://forestry.about.com/od/treeplanting/p/oak_acorn.htm
http://www.wildbirds.org/oaks/oaks.htm
http://www.fs.fed.us/psw/publications/documents/psw_gtr126/psw_gtr126_01_tietje.pdf
http://www.laparks.org/dos/parks/elysianPK/pdf/3A.pdf
http://www.scholastic.com/parents/resources/article/craft-activities/hanging-bird-house
http://www.a-home-for-wild-birds.com/bird-house-placement.html
http://www.nwf.org/News-and-Magazines/National-Wildlife/Birds/Archives/2010/Best-Bird-Houses.aspx
http://www.spruce.net/birds/placement_v2.htm
http://www.biologycorner.com/worksheets/owlpellet.html
http://www.kidwings.com/owlpellets/flash/v4/index.htm
http://www.obdk.com/pdf/dissectionlab.pdf
http://www.pelletlab.com/barn_owl_pellet
http://www.lpscience.fatcow.com/jwanamaker/download/owl_pellet_lab.pdf
http://www.hometrainingtools.com/owl-pellet-dissection-project/a/1244/
http://www.energiseforlife.com/wordpress/2006/04/12/alkaline-test-how-to-test-your-ph-levels-saliva-urine/
http://www.indigo.com/ph_acids_and_bases/
http://chemistry.about.com/od/chemistryhowtoguide/ht/makephpaper.htm
http://www.webmd.com/digestive-disorders/tests-esophagus-ph-test