Gwyneth Lewis's highly inventive Sparrow Tree puts nature writing in a spin, presenting a huge variety of birds, both British and American: blue tits, blackbirds, egrets, juncos, starlings, herons and hummingbirds as well as the sparrows of the title. The book explores birds as mouthpieces for inhuman song and the wild inside the mind. Launching flights of avian fancy or fantasy on several levels, Sparrow Tree moves from birdsong as proto-language to birds as decorative beings. The collection includes her already well-known How to Knit a Poem, commissioned by BBC Radio 4, and ends with images of the human word as a form of love.