Joan E. Strassmann in The Common Reader:
There are three main themes to this book. First, people revered eagles and used them and their images to define their group, be it native or settler. Second, people killed bald eagles by the thousands, nearly wiping out this magnificent bird, a job that DDT practically completed. The third theme is redemption and shows the efforts some people are making to rescue our emblematic bird.
The first chapter, Searching for a Seal, was one of my favorites because of the way it showed the development of something that seems so timeless, the seal of the United States, the seal that is on every podium, every official banner, and every dollar bill. Now it seems almost inevitable, but there were several other contenders that might have prevailed. Our great seal shows a bald eagle looking left holding in its bill a ribbon that says E Pluribus Unum, from many one. But you know the rest of the image or can easily pull it out of your wallet.
More here.