Some birds tuck a leg up when it’s time to rest, letting one leg take all the weight while the one tucked up gets a proper break. And then switch.
This seagull just has the one.
And, unlike some birds that lose a leg and struggle to adapt, this one appears healthy, well-fed, and alert. There have certainly been adaptations to feeding, resting, swimming, and other gull activities.
Where are you struggling to stand? And can you see a way to adapt?