what does "I am, etc" mean? I should now proceed to such birds as continue to sing after Midsummer, but, as they are rather numerous, they would exceed the bounds of this paper: besides, as this is now the season for remarking on that subject, I am willing to repeat my observations on some birds concerning the continuation of whose song I seem at present to have some doubt. I am, etc.】 this is the last paragragh of a letter, I don't understand the Signed part, what does "I am, etc" mean?