Everything You Wanted to Know about Bird Body Systems

June 22, 2021

A review by Alex Troutman

How Birds Work: An Illustrated Guide to the Wonders of Form and Functionfrom Bones to Beak, by Marianne Taylor

The Experiment, 2020

227 pages, flexi-binding

ABA Sales–Buteo Books 15040

WOW, what’s not to love about this book? The amazing cover of a Baltimore Oriole transforming from a blue line schematic to a photograph of the bird immediately captivates you with a sense of awe and wonder, and the motion of the bird suggests how the reader is about to “fly” into this book. It reminds me of a blueprint to an airplane, which is quite funny because airplanes are a biomimicry product molded and designed after avian flight.

How Birds Work brings back the nostalgic childhood memories of Zoo Books and the DK Eyewitness Books. The text is straightforward and accessible, making this not just a book for ornithologists and other bird lovers, but a book that even middle school readers can enjoy. Marianne Taylor does a wonderful job of conveying the science of How Birds Work without overwhelming the reader. She provides detailed photos and diagrams. One of my favorite photos happens to be of the Bald Eagle on p. 45. The magazine cover–worthy image really captures the elegance of a Bald Eagle and at the same time highlights its fierce demeanor. Another of my favorite photos from the book is the image of the bathing Hooded Merganser on p. 67—it’s another stirring image that captures the beauty of the bird subject.

While the title is How Birds Work, you’ll learn about a few more animal groups than birds. The book feeds us little tidbits of information about other animals, one such example being the Comparative Animal Flight section from Chapter 2, where the reader learns that “powered flight has evolved four times in the animal kingdom—in birds, bats, the prehistoric pterosaurs, and winged insects” (p. 52). Taylor gives a glimpse powered flight evolution by sharing images and facts about each of the four evolutions of flights. How Birds Work does a great job explaining the similarities between birds and their non-avian counterparts.

How Birds Work is a step-by-step diagram on how to build a bird. The book is made up of twelve chapters, and in each chapter the reader learns one of the body systems of birds, from the skeleton system in Chapter 2 to Chapter 12’s coverage of colors, pigmentation, and patterns.

Chapter 1 gives the reader an introduction to birds by explaining the ancestors and evolution of birds. You’ll learn about early birds such as Archaeopteryx, a fossil bird that roamed the Earth over 150 million years ago. Darwin’s finches make an appearance too and give the reader an example of evolution through changes in bill size and diet. Chapter 1 concludes with cell division and biology, leaving us two images of animal cells to ponder as we head into Chapter 2.

After learning about the evolution and ancestors of birds, in Chapters 2 and 3 you dive headfirst into learning about the skeletal and muscular systems of birds. You learn new and interesting facts and are reminded of ones that slipped your mind, like how ostriches and other ratites are the only birds alive today without a keeled sternum. Chapter 3 starts off with an overview of the muscular system of birds, and then leads into a detailed breakdown of some of the important muscles for feeding and flight, plus other muscles that aid in locomotion. This chapter uses fascinating still shots of a hawk to walk us through the movement required to achieve flight.

In Chapters 4 and 5, Taylor takes readers through the wonders of the nervous system and bird senses. In Chapter 4, we learn key parts of the nervous system, from axons and dendrites to neurons and the spinal nerve. Taylor explains how the nervous system is responsible for birds’ day-to-day activities, among them: recognizing social cues, regulating temperature, and song. Chapter 5 takes us on a journey through bird senses. Readers will learn how having eyes is just one of many factors that aid in the success of birds of prey, how brow ridges and eye placement enhance bird sight, and how not all bird eyes are the same. We also learn how eye shape and size have led to unique adaptations in bird morphology—for example, how the range of motion in owls’ necks is a compensation for the birds’ larger eyes filling the birds’ skulls and limiting movement. Chapter 5 also showcases some of the “super” senses of birds. For example: woodpeckers that hear beetle larvae feeding in tree trunks; and songbirds that sense the Earth’s magnetic field and use it to aid in migration.

Chapters 6–8 are all about the major body systems of birds, among them the circulatory, respiratory, and digestive systems. The material is integrative, explaining, for example, the diverse adaptions that aid in dietary success: bill size and shape, highly acidic digestive tracts, and fermenting gut bacteria. Chapter 6 explains how the circulatory system is important not only for regulating blood flow, but also for the circulation of hormones and disease-fighting antibodies of the immune system throughout the body of a bird. Chapter 7 explains bird sounds, detailing the different features and functions that allow birds to sing; we learn how air circulation is a major tool in producing sound. Getting airborne is difficult if a bird weighs too much, and, in Chapter 8, we learn how birds deal with this problem. For example: by drinking small amounts of water, as well as by reabsorbing water that has already been ingested.

Reproduction and development are the focus of Chapters 9 and 10, presenting reproductive anatomy, the breeding cycle, and egg-laying strategies. Particularly fascinating is brood parasitism: when a bird lays eggs in the nest of a different species. The parasite’s offspring hatch first and then either push the eggs of the foster species out of nest or outcompete the offspring of the foster species by having a head start over them. The host parent appears unaware that the usurper is not her own biological offspring. Chapters 9 and 10 also highlight success stories like the captive breeding and subsequent release of California Condors. In these two chapters, embryo and egg development are well presented. We learn about two different developmental strategies—altricial and precocial—and the birds that utilize them. Chapter 10 also introduces the special tools that young birds use to ensure survival, from camouflage to gape markings.

Chapters 11 and 12 put the icing on the cake—or, should I say the feathers on the bird! These last two chapters cover birds’ feathers, skin, and color. Readers will learn why certain bird have webbed feet and naked legs, while others have lobed toes, while still others have feathers continuing down their legs, as if wearing pants. In these two chapters, the reader is also exposed to feather physiology and maintenance, along with pigmentation and how feather colors are used to attract mates and foil predators.

How Birds Work is a new favorite book of mine. It’s filled with solid, detailed information delivered in a way that allows for comprehension without loss of valuable content. Now combine the information with the splendor of the accompanying pictures and diagrams, and you have a great book that is guaranteed to grab and keep the reader’s attention. The reader truly will have learned How Birds Work at the completion of this book.


Alex Troutman is a wildlife biologist, birder, nature enthusiast, and science communicator. He has a passion for sharing and immersing the younger generation in nature. Alex is a graduate student at Georgia Southern University, where he studies arthropod diversity and the diets of Seaside Sparrow nestlings in tidal salt marshes.