Regarding the American Avocet at RMBS (St. Charles Co.) - It appears it is not quite the latest fall record yet. I have just begun going through the seasonal reports since Robbins' and Easterla's Birds of Missouri was published and found the following:
Nov. 19, 2007
(1); Squaw Creek NWR, Holt Co.; Larry Lade; BB 75:10.
St. Louis County, MO[log in to unmask]
Bird Photos: http://www.pbase.com/jpuf