From page 50 of Bird Brain:
Hummingbirds in the Rocky Mountains have adapted to solve a difficult spatial problem. They feed on flower nectar, but each flower has a limited amount of nectar that only replenishes itself after a certain amount of time. Within a field of thousands of flowers of the same color, hummingbirds have to keep track of which flowers they have previously emptied and how long before they will be full again. They feed every ten to fifteen minutes, so keeping track of food stores is a constant task. Because of this, they have evolved a high level of spatial awareness—it is particularly impressive when you consider that the hummingbird brain is the size of a grain of rice.
Birds have not been known for their high IQs, which is why a person of questionable intelligence is sometimes called a “birdbrain.” Yet in the past two decades, the study of avian intelligence has witnessed dramatic advances. From a time when birds were seen as simple instinct machines responding only to stimuli in their external worlds, we now know that some birds have complex internal worlds as well. This beautifully illustrated book provides an engaging exploration of the avian mind, revealing how science is exploding one of the most widespread myths about our feathered friends—and changing the way we think about intelligence in other animals as well.
Bird Brain looks at the structures and functions of the avian brain, and describes the extraordinary behaviors that different types of avian intelligence give rise to. It offers insights into crows, jays, magpies, and other corvids—the “masterminds” of the avian world—as well as parrots and some less-studied species from around the world. This lively and accessible book shows how birds have sophisticated brains with abilities previously thought to be uniquely human, such as mental time travel, self-recognition, empathy, problem solving, imagination, and insight.
Written by a leading expert and featuring a foreword by Frans de Waal, renowned for his work on animal intelligence, Bird Brain shines critical new light on the mental lives of birds.