It’s no mystery why this common bird here is called a ring-billed gull. It’s as plain as the nose on his face. What is a mystery is how he can stand the winter cold without pants and socks on those skinny legs and wide webbed feet.
It turns out that, basically, seagulls have a heat pump system that uses the blood running up and down their legs and into their feet. As I understand it, warm arterial blood flows down to the feet and passes heat to the chilled venous blood returning to the body.
This mature ringbill (Larus delawarensis) is in his spotted, non-breeding winter plumage. The yellow or greenish-yellow legs of adult ringbills help differentiate them from other gulls at a distance. They also have fully-webbed feet. These allow them to swim well in our cold winter waters, which sometimes are warmer than the ambient air (but still brrrr).
(Images taken in Blue Hill, Maine, on November 25, 2025; sex assumed.)