Sideburned gull

I’ve never seen anything like it! My best guess is that it was injured at some point and this is how its feathers regrew. It doesn’t have these muttonchops on its right side.

   6 January 2024
   1/1600s    f/5.6   400mm   ISO 1600
A Glaucous-winged Gull sitting on a log in the water and scratching itself. It has an unusual dark patch of feathers on one cheek