Jeanne Birdsall, author of the adult-pleasing Penderwick books, also wrote the Cybils Fiction Picture Book Finalist, Flora's Very Windy Day. Flora, a gently misunderstood older sister, is banished with her messy little brother to the outdoors, despite the danger from the strong wind. Flora is safe, but as she predicted and her mother dismissed, her younger brother is blown away. Flora goes after him, because that's what big sisters do.
The pictures and the text complement each other delicately, with the comforting love between the siblings evident even as Flora finds very uncomplimentary reasons to save her brother. The sparrow can't have him for an egg-sitter, because he's so clumsy he'd break all the eggs. Both boys rocketed this to the top of their picture books choices, but I'm still holding onto Chalk. A-
I think the Amazon link benefits the Cybils committee. If I did it right.