Juncos use their feet more than many birds, not just to perch but to hop about while feeding. Their legs and feet, viewed close, are a contradiction: incredibly slender and fragile-seeming, but also covered in a hard, scaly, tough surface. You hope for their sake that the fragility is the illusion and the toughness reality, but of course each is a little true.
LANK has a permanently bent toe on his right foot. When he perches, his weight rests on what should be the top of the toe, and I imagine the same is true when he stands on the ground.