For those presumed young readers who prefer their natural history in the form of an individual life story, this follows barn owl Tyro from his hatching in the Holdern's barn (his father ""well pleased"" with the sight) through a two-year odyssey that starts when his parents, with a new batch of young to feed, drive him from their nest. In the course of his travels Tyto makes his home in a church, a water tower, and a quarry--this last a ""promised land"" swarming with rats until a polecat and other predators arrive to finish them off. Tyro mates first with Brilla, who is slowly dying of insecticide poisoning, and whose eggs--though their appearance gives Tyto the ""greatest feeling of fulfillment he had ever known""--are too thin-shelled to survive; then he pairs with Alba, most of whose young fall victim to various human and other forces. At last, driven by insensitive nature photographers to abandon their eggs and nest, Tyto and Alba, aided by the latter's ""instinct and inbuilt navigational skill,"" return to the farm where he was hatched--and where young John Holdern has been missing him throughout. Steady going.