iii. About the Cover

The common starling, pictured on the cover of this book, seems just that: common. It isn’t particularly large — roughly only 8 inches long. It isn’t particularly musical and is considered noisy in flocks and communal roosts. It’s also not particularly beautiful, with dark glossy feathers and a subtle metallic sheen.

And, yet, this simple bird continues to hold our attention, even being referenced in literature as early as Shakespeare. Why?

First, it has a talent for mimicry and, like the reactive sensibilities explored in this book, is highly responsive to its environment. It has up to 20 distinct imitations of other birds, and it is even known to mimic ringing phones and car alarms.

And, most impressively, a flock of starlings in flight is a gorgeous display of reactivity in motion. You’ve probably seen it, yourself: thousands of birds creating fluid shapes — called murmurations — in the air, never pausing, each bird responding to the next.

While we can’t know how these birds evolved to this level of cooperation and responsiveness, we hope to draw some inspiration from them in this book as we guide you through developing your own reactive programming.

You can learn more about these birds, here: https://en.wikipedia.org/wiki/Common_starling.

See them in flight, here: https://video.nationalgeographic.com/video/short-film-showcase/00000158-457d-d0be-a1dc-4f7f8e650000.