Sam is very picky about his nonfiction - specifically about whether it has that ineffable spark that elevates it to literature. He thinks very highly of Moonbird - highly enough that he used the big L word (no, not that one). I'm not sure I agree.
I see where Sam is coming from in terms of Hoose bringing the personal into nonfiction. The best nature writing - some of the best literary nonfiction in general - employs that technique, but it doesn't often make its way into children's books. When's the last time you read a juvenile informational book that used the first person singular outside of the author's note? Hoose does set himself apart by weaving his own experiences into the story of B95 and the other red knots.
Does he do it in the most distinguished way, though? I don't think so. Stylistically, this book falls on the "good" side of the good/great divide. The settings are described vividly, the organization is effective, the profiles of people working in the field add texture... but none of it really thrilled me. I wasn't captivated by B95's plot arc in the way I was while reading about the plight of the Titanic and the quiet triumphs of Temple Grandin.
And what about character? Hoose does an excellent job of turning an unassuming little shorebird, B95, into a literary hero, and thus giving the reader a point of interest to follow through the book. But how does B95 compare, as a character, with Mr. and Mrs. Bunny? With Parsefall and Lizzie? With Georges and Safer? Not very well, I would argue.
Sorry, Moonbird. If you're still alive, I hope you're not crying little Patagonian birdy tears of literary unworthiness all over the restinga. You're still the star of a very good book.