Science and Nature Guides Birds
I found this book at my local libraby. For this book, since it is the first day of the unit study I plan to just look through the book with them and possibly read some short parts of the book. Mostly, I am just using this book to peak their interest in birds. I will also keep this book around as a reference tool while we go through our unit study.
A few ideas for discussion while looking through this book might include:
colors of the birds

birds in your state
what different foods the birds eat
God made the birds
On this day I would also show them a movie pertaining to birds. Reading Rainbow has a movie called Birds of a Feather. I found this book at my local library.
The main focus of the first day is just to get them interested in the subject that you are about to cover.