Talk:Pearl Dragon/@comment-107.201.188.10-20130623132429/@comment-187.70.63.161-20130625191015

The island does increase (in comparison with the cave).

Upgrading an island (or a cave) doesn't directly increase the chances, but you are reducing your time... so you will have more attempts... and that indirectly increases your chances.

One thing that might be missing on your math: How many attempts have you made so far? My two Pearls came on the 17th and 56th attempts.