At this point, the chick doesn't have feathers yet, and its eyes are tightly shut. This nest encloses the baby birds, and helps keep them warm. The female hummingbird makes the nest out of grass and twigs, held together by spider webbing collected by the mother bird. The growing chicks stretch the soft nest. That's when they begin flying out and foraging on their own.
Hummingbirds often return to the same nest year after year.
Nikhil, thanks for your question. And with thanks to the National Science Foundation, we're Block and Byrd for Earth and Sky.