David Barrett earned his undergraduate degree in mathematics from Harvard, and did graduate work in mathematics at MIT and in finance at the University of Chicago. After a long career as a hedge fund manager he is now an investor and computer scientist. Other interests include bodybuilding, running, and, of course, birding.
As he explains in his book, he initially began birding in November 2010 as a way to make his long walks in Central Park more enjoyable. He was already doing all the training he could handle as a middle-distance runner, and believed that extra walking would provide an additional training stimulus without requiring longer recovery. He quickly began to enjoy birding for its own sake, however, and became as obsessive about observing new bird species as he had been about lowering his mile times.
His lifetime total of 261 bird species in Manhattan, where he lives, places him second on eBird’s all-time list as of January 2018.