These are chicks that live around my office (photographed from a window).

Gull chicks are precocial and they leave the nests to wander about a bit. How they get from the high nests to the ground is not entirely clear to me, maybe they flutter down or simply fall down and survive it, as I don't think the Gulls make nests on the ground, but usually on roofs. The chicks tend to stay in a general area, but sometimes they have disappeared, moved on or caught by a cat I suppose.