Rudy recommends Handbook of Nature Study by Anna Botsford Comstock as a good general book for nature study.
Anna Botsford Comstock (September 1, 1854 – August 24, 1930) was an acclaimed author, illustrator, and educator of natural studies. The first female professor at Cornell University, her over 900-page work, The Handbook of Nature Study (1911), is now in its 24th edition.