1) The weathervane has a groove built into its tail. The groove was created to increase the strength of the tail.
2) The tail may have been repaired at some point in time based upon the plate nearest the post. The plate wraps around the post and sandwiches the tail. This could mean that the tail was at one point much longer than it is today.
3) The tail and ball are made of copper, but the arrow portion is made of an unknown alloy (possibly pewter).
4) The ball is created from four separate pieces.
5) The weathervane likely dates to 1713, meaning it is original to the building.
6) The weathervane may have been built by Shem Drowne, a noted copper and tin smith who created the Faneuil Hall Grasshopper Weathervane.