What purpose do the descriptive passages from Berwick's History of British Birds serve at this stage of the text?

Jane reads Bewick's History of British Birds in Volume One, Chapter One of Jane Eyre. This history describes the habitats of wild "sea-fowl" as cold, isolated places where the tumultuous ocean "whirls" and "boils" around the shore. These images not only feed the young Jane's imagination, but also serve as a symbol for Jane's separateness and isolation in Mrs. Reed's home. While Mrs. Reed's own children are treated with warmth, Jane is coldly treated as an outsider. This bird imagery, however, also brings up the theme of freedom, which is something Jane will later pursue.