What an Owl Knows: The New Science of the World’s Most Enigmatic Birds (2024)

Jennifer

Ackerman

What an Owl Knows is a thoughtfully written and engaging work by Jennifer Ackerman, an acclaimed and award-winning author of The Genuis of Birds (2016) and The Bird Way (2020), where Ackerman launched readers into the wonder and peculiar antics of the avian world. Those earlier works enthralled lay readers and avian scientists who thought they knew it all, but quickly learned otherwise. Ackerman’s books are a who’s who of modern avian researchers their and innovative approaches to examine an array of species, behaviors, and life histories. Ackerman’s style is approachable for a range of readers, is evocative, and most importantly to me (an avian scientist), she supports each story with scientific evidence and a trove of sources for further reading. Ackerman is a world-traveling continent hopper who encounters birds in diverse and fascinating habitats and cultures that belie an impressive personal awareness and respect of place and social context, all linked by her intensely felt respect and passion for not only the birds but also the people who study them.

Following previous work, in What an Owl Knows Ackerman turns her focus to owls, and has stepped squarely into my world (I have studied Mexican Spotted Owls [Strix occidentalis lucida] in the southwest USA for 30 years). In my naiveness, and some measure of owly arrogance, I wondered if I already knew most of what was coming; however, right from the start I learned new and relevant aspects of owls I was not aware of, and in each chapter read about engaging work by scientists and volunteers pushing the boundaries of owl knowledge. I became increasingly excited and interested in a group of birds I thought I knew a lot about, and my sense of wonder and mystery for owls and my own research was rekindled. I was hooked right away by the author’s statement that owls are “powerful symbols…hard to study in the wild…and they’re quiet, wary, secretive, and often elusive.”

A key element of her writing that resonates throughout her book is how Ackerman focuses upon the most current studies and new insights by the research community who use innovative tools and technologies, including DNA analysis, artificial intelligence algorithms, telemetry, drones, acoustic recording devices, remote videography, the olfactory heroics of trained sniffer dogs, and a plethora of inventive capture and monitoring techniques. In doing so, her book provides insight and ideas for my own research, and each chapter reveals science-based cutting-edge approaches.

What an Owl Knows includes 9 engaging chapters, an Afterward concerning owl conservation, and an excellent bibliography of sources. In chapter 1, “Making Sense of Owls,” Ackerman provides a foundation of owl evolutionary descent, genetic origins now thought to stem from birds like Trogons, Hoopoes, and Kingfishers (Wink and Sauer-Gurth 2021), and a review of the range of owl life histories and habitats that showcases those adaptive traits that have evolved over millions of years. In chapter 2, “What It’s Like to Be and Owl,” Ackerman describes how owls might be described as flying cats, or “wolves of the sky.” Ackerman describes the often gruesome, perhaps ruthless, and sometimes playful cat-like behaviors that owls use to dispatch prey with almost brutal detachment. Although I found parts of the language a bit anthropogenic, the diversity of prey that owls sortie for is well described and quite astounding, from scorpions and hummingbirds, to bats and mice, and even cervids by the larger owl species. Comically, Ackerman quotes a researcher who describes an owl as “an anything-I-can-shove-down-my-throat specialist”—a wonderful killing machine. Importantly, with this chapter Ackerman also digs deep into physiology and anatomy of owl hearing and vision and how these systems are intricately connected. I was fascinated by the seminal work of Mazakazu Konishi (Pena and Konishi 2001) and colleagues, who explored, among other things, interaural sound reception and the keen ability to fix the location of prey in zero light. Additionally, I found the argument presented for space-specific neurons averaging incoming signals using Bayesian inference to be compelling (Fischer and Pena 2011). Ackerman provides a fascinating exploration of vision genes, night vision, and new studies that document retinal rod cells sensitive to ultraviolet light and why that might be important (Höglund et al. 2019). Compelling too are the neural links between sight and sound and the provocative hypothesis that perhaps sounds are projected onto a visual map, so that an owl sees the source of the sound.

In chapter 3, Ackerman presents the clever and varied ways by which researchers detect, survey, observe, and catch a variety of elusive and cagey owl species. I found the section on sniffer dogs used to find regurgitated pellets, feathers, roost, and nest sites fascinating. Ackerman explores a variety of so-called “Rogue Detection” methods and provides new insights toward non-invasive methods to detect owl presence, including dogs, acoustic detectors, infrared cameras, and drones that may offer effective techniques to replace more invasive approaches like call broadcast surveys and capture–mark–release methods. I did squirm a bit as Ackerman’s writing might depict owl biologists, such as myself, as a cavalier bunch of laypersons who utilize cowboy-like techniques to capture and study owls. To the contrary, we go through detailed scrutiny to obtain International Care and Use Permits to gain approval for any technique or protocol that might cause stress or harm to our owl subjects. We apply for a phalanx of permits from state and federal agencies, the bird banding labs, and then file detailed reports about our progress.

Within chapter 4, Ackerman provides an excellent review of owl vocal behavior that serves as both a great refresher for those with expertise and a very fun primer for people new to owl calling behavior. There are several very interesting accounts of distractive display by owls, and chick vocalizations from within the egg. Ackerman also presents exciting new information about ultraviolet light reflection and potential functions of this unique aspect of bird sight and spectral reflectance of feather elements. In chapter 5, Ackerman focuses on courtship and breeding behavior, and showcases the impressive work on owls conducted by Denver Holt (Holt 2022) among others. I found her discussion of why Snowy Owls (Bubo scandiacus) are white quite engaging, but wondered too if a thermal hypothesis might be included. In chapter 6, Ackerman provides insights into owl natal dispersal and migration, and roost behavior. I found her discussion about one-eyed sleep, its physiology and function so very interesting, and her section describing group roosting sites in Serbia, where over 145 Long-Eared Owls (Asio otus) shared a roost tree was astounding. With the following chapter, Ackerman provides a rousing discussion of the techniques of devoted volunteers who spend countless hours rehabilitating and providing long-term care of captive owls who cannot succeed back in the wild. Within this chapter, Ackerman provides an important discussion of the ethics and cultural complexity of the use of owls for entertainment, spiritual values, and she reflects on the emotional connections between humans and captive birds. I found this chapter particularly thought provoking, and perhaps best summarized by the quote from Henry Beston, “They are not brethren, they are not underlings; they are other nations, caught with ourselves in the net of life and time.”

Chapter 8 is a deep dive into the cultural history, mythology, and spiritual connections owls generate for humans. The chapter is a fascinating review concerning the powerful myth and cultural symbols that owls have represented for over 30,000 years, such as in cave paintings of western Europe. In the book’s final chapter, Ackerman provides a compelling summary of what she has learned throughout her experiences with the research community and the owls themselves. What an owl may know goes well beyond the visual, auditory, and synaptic abilities of humans, and it is clear Ackerman is in awe of what she learned and experienced in the creation of her book. And there is still so much to learn. This final chapter reflects on the wisdom of owls, the potential for emotions, and even the community service provided by owls, not only ecological but also the service provided to human communities via personal inspiration, connection to nature, and even individual wellness. The Afterward is a thoughtful essay on the road ahead for owl conservation and a call to arms for humans in the face of significant global changes and challenges for owls worldwide. The final story of an Elf Owl’s (Micrathene whitneyi) evocative interaction with a human being seeking solace was powerful, and I felt inspired and, quite frankly, overwhelmed with gratitude to the author and the owls. I applaud both the author and the many scientists who invited Ackerman to join them in the field. I think that the attention this book generates will create a following that forms a constituency to vote and act for birds, for owls, for conservation, and for respect of the planet.

Jennifer Ackerman has produced a solid history of impactful books that have drawn a horde of people to birds. I respect the hard work and diligence that was required to produce What an Owl Knows. Throughout my reading I found nuggets of new facts, hypotheses, and my awareness of other researchers was expanded. A special moment in my reading was during a passage about the linkage between hearing and sight. Ackerman led me to experience what an owl knows as though I was an owl, seeing the land in first-person view: I closed my eyes and was aware of a blended sight and sound crosshair that locked in on tiny sounds of a packrat in a black canyon alcove in Utah. The light from the prey was visually precise and illuminated the canyon walls. The prey was a beacon for my sortie. Ackerman inspired an illuminating vision and insight and I am very grateful.

In summary, I found the book very well organized, beautifully written, and the crescendo-like movement of each chapter toward the climax of the book was thoroughly enjoyable. Importantly, Ackerman’s writing approach and bibliography provide a relevant resource for scientists and students. What an Owl Knows is an engaging and fun book, full of general knowledge for the lay audience. This book would make a valuable resource for any collection and will inspire a diverse audience.

Book Review Editor: Jay Mager, jmager@americanornithology.org

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