Beautiful and sharp in-action photos! I always thought the red part of the lower beak was blood from eating all the fish innards!
Beautiful and sharp in-action photos! I always thought the red part of the lower beak was blood from eating all the fish innards!
Thank you for your encouraging comment. Unfortunately, I don't know anything about the red spot's function.
I might have found the answer! It's appears to basically be a target that gull chicks can easily spot, so that they know where the food is. (Source)
Thank you so much for the investigation and your answer, @mightpossibly