I think the falling action is after they rescue Mrs. Peregrine. I think that because when they rescue her that’s when the action kind of stops. This is also right after the climax .After they rescue her the action starts to die down.
An important symbol is the peregrine falcon. It represents Mrs. Peregrine as her bird form. All ymbrynes can turn into birds and Mrs. Peregrine is a ymbrynes so she turns into a bird. And in the book all birds can manipulate time which can protect Mrs. Peregrine and the children. Ymbrynes can manipulate time when they want while normal birds in this book just do it by accident. Jack and his dad see her in bird form when they coming on to Wales.
I think the end of the book is when Jacob joins the children in the loop. It was a hard decision to do this because me loved his grandfather but liked the children in the loop. This is where the book ends.