Birds are more like humans than many realize: they are bipedal, they rely primarily on sight and hearing, and most are monogamous. Birkhead, a professor at the University of Sheffield in England, has spent his career studying bird behavior and fills his book with evocative stories and observations about numerous species, including flamingos, parrots and his beloved long-tailed sylph hummingbird. Each chapter is devoted to a particular sense or trait—“Touch,” “Hearing,” “Seeing”—with “Emotions” being one of the most nuanced. Birds perform increasingly elaborate greeting rituals the longer they have been away from their partner, he writes. Does that mean they experience feelings the same way humans do? Birkhead is reluctant to draw a conclusion, letting the observations speak for themselves.