For additional questions, I suggest you contact Bill Wendell at Wendells@erols.com. The file had a companion which may have explained further, but it is unreadable. I am putting this on the list in case others receive the file and have the same types of questions. The rest of you can ignore it. Fran -------------------------------- Fran Saunders Maryland Ornithological Society State Web Site Director saunderf@ari.net http://www2.ari.net/saunderf/mos/mos.html