This is a rare collectible antique silver thimble with waterfoul.  It is a size 10, the hallmarks have worn leaving only a faint image of an anchor (see photo). It is well used and worn and thusly misshapened (see photo).

The engraving style features a classic folk art aesthetic, with alternating geometric panels and bird motifs. Antique thimbles with this exact decorative configuration—alternating diamond/geometric stamped grids alongside etched songbirds or waterfowl—were widely produced by historic silversmiths during the late 19th and early 20th centuries.

Condition is good, but well worn.  Tested sterling.