Large format book, excellent illustrations. Interesting story of the house sparrows migrations with the Roman legions to Britain, and elsewhere. Importation of the house sparrow to the US. Decline in the population in the last century, in part because of the decline of horses. But I don't think the house sparrows "discovered" that incorporating cigarette butts into their nests reduced the number of pathogens that attacked their young, in any regularly understood meaning of the word "discovered". ( )