This is a visually spectacular book. Hummingbirds, so beloved by the public, are already the subject of many books that range from mawkish to good. None accurately summarizes hummingbird biology for a general audience in adequate detail. As this book features eye-catching photographs and diagrams as well as a lot of text, my initial hope was that this book might finally be the go-to general reference on hummingbirds. It isn't. This is another book you should buy for the photographs.
A public audience will love this book for the pretty pictures and text that is always clear, engaging, and written with a tone that seems authoritative. The chapters in the second half of the book, on biogeography and biodiversity, culture, and conservation, are excellent. The habitat pictures are great. The one thing that would have improved the biogeography sections is a map of South America showing each biogeographic region featured. Many readers won't know where the Atlantic Forest is, for instance.
The first half of the book is a mixed bag. I noticed descriptions of recent research such as Maude Baldwin's work on taste receptors, Cassie Stoddard's work on nonspectral color perception, and Alejandro Rico-Guevara's work on drinking. This new work is complicated and the book explains their findings both lucidly and correctly for a public audience. Yet despite clearly putting a huge effort into synthesizing certain recent research, elsewhere the text uncritically presents the shopworn factoids that plague other books on hummingbirds. The flight section (page 19) claims hummingbirds flap their wings 200 times per second in displays, fly upside-down, and can fly 60 miles per hour in level flight. Other false claims were new to me: hummingbirds are said to increase their wingbeat frequency to conserve heat in cold conditions (page 21), or “males may be brightly colored to attract the attention of predators and draw them away from females” (page 58). Page 106 states that the Giant Hummingbird is unique in laying just 1 egg (rather than 2). You can disprove this one in seconds with a Google image search. Page 112 claims that “although hybrid hummingbirds are not uncommon, they are infertile and do not persist beyond the first generation.” But several hummingbird hybrid zones are known. And so on. Just as you only have to uncover one rat dropping to make you stop eating an entire bowl of oatmeal, inaccuracies like these, although small in number, nevertheless render the text unreliable. As there are no in-text citations, I don't know whether these facts come from bad sources or were ad-libbed. For that matter, although the photographs are all carefully given proper attribution, that's not true of the science. The book's text describes findings from at least 5 of my papers, but the references section (an online file, downloaded 1 Aug 2022) doesn't cite any of them.
The preface states that one goal of the book is to provide an up-to-date overview of hummingbird biology. For an overview, its coverage is uneven. There is an extensive section on coloration—not surprising, because this book is mainly a vehicle to deliver beautiful hummingbird pictures for your eyes. But this section is too long: It has paragraphs that veer into speculation about female preferences and the handicap principle (page 60), yet there are no relevant data on these topics for hummingbirds. Meanwhile, well-studied, unique aspects of hummingbird physiology, such as their amazing kidneys, sugar metabolism, or muscle physiology received virtually no mention. My guess is these topics received limited attention for the understandable reason that physiology does not pair particularly well with pretty photographs. But other omitted topics would work perfectly with the right photo. The section on sexual dimorphism (page 82) ignores Ethan Temeles's work on bill dimorphism and foraging ecology. The treatment of foraging ecology, territoriality, aggressiveness, and fighting are superficial and there is no mention of those strange mites that hummingbirds carry in their noses (I'm pretty sure I could see a few in some of the pictures). These are flower-related topics and so would pair perfectly with lovely photographs of hummingbirds and their flowers.
The photography is indeed amazing. This book tops all previous books for the beauty of the imagery. Hummingbirds are difficult to photograph because they are small, fast, and hard to light. Thus each photo is the product of patiently waiting for hours for the right bird to come to the right spot. Glenn Bartley has mastered the same lighting technique used by earlier generations such as Tyrrell and Tyrrell (1985) or Luis Mazariegos (2000) in their pioneering, spectacular hummingbird photo books. Glenn's pictures are even better than theirs, likely because these older books were mainly shot on film, which required developing, while digital photography lets Glenn instantly see if an image is good. Glenn's pictures also have a certain sameness. Here is how I would describe most of them: an adult male in immaculate, freshly molted plumage showing no fault bars or missing or broken feathers, sits or hovers next to a gorgeous, unidentified flower. Like a TV show about relatable, regular people where all the actors are young supermodels, the photos are too beautiful. In this respect, aesthetics conflicts with biology, and aesthetics wins. Female hummingbirds have interesting biology too, but you would barely know it from the photos in this book.