Erwin, R.M. and T.W. Custer. 2000 . Herons as indicators. Pages 311-330 in J.A. Kushlan and H. Hafner, eds. Academic Press,London UK. Keywords=herons, biomonitoring, indicators, contaminants End_keywords Notes= submitted by rme5g@virginia.edu, Tue Jul 17 10:50:25 EDT 2001 End_notes