Note to correspondents and one more acorn

Mystery acorn #4- What am I?


NOTE: If you write me for the first time please include a clear nature subject in the subject line -- like "Acorn ID" or "hawk question" or "I love Moths" or the like. If an e-mail arrives with no subject, or with a word like "confused" or "Disagree" etc. in the subject line, I assume it's spam and delete it without reading.