There's an old legend that insulators were made in different colors to attract different kinds of birds. Well we know that's not true, but some insulators do attract some birds. Here is a CD 133 EIN [520] (F‑Skirt) W. BROOKFIELD (R‑Skirt) NEW YORK SB that I found in a box lot, and when I cleaned it up, I saw it had a small, white potstone above the W in the front skirt. Apparently, so did some birds because that potstone is literally surrounded by seven or eight surface "pecks" where the birds couldn't get at the little white "bug" in the glass. 8^D Click on View Original for a closer look.