Yarrell was born the son of a newspaper vendor in central London. He enjoyed the reputation of being the best anglers in London before he became a renowned naturalist. In 1825 he was elected to the Linnaean Society and was soon their treasurer. In addition, he belonged in 1826 to the founding members of the Zoological Society of London. His ornithological chief merit was the first description of dwarf swan in 1830. Too, as the author of two books, The History of British Fishes (1836 ) and The History of British Birds (1843 ) he became very well known. He also wrote articles for the journal Transactions of the Linnean Society of London.
Several species are named after William Yarrell, including the Aricaelfe ( a hummingbird ) ( Eulidia yarrellii ), the Yarrellzeisig (Carduelis yarrellii ), the bush carrier ( Chirolophis ascanii ) ( species, which is called in English Yarrell 's blenny ) and the Pied Wagtail (Motacilla alba yarrellii ).