The Book of Birds delivers a stark warning in its introduction about the “great thinning of the skies … Dawns and springs are quieter; the air emptier. An ancient avian orchestra is falling silent.” There are now 3 billion fewer birds in North America than there were 50 years ago, and 5 million fewer in Europe. Across the world, almost 50% of bird species are in decline. These figures are the galvanising force behind writer and illustrator Jackie Morris and nature writer Robert Macfarlane’s compendium of 49 bird species under threat in Britain. Each entry is a prose poem aimed at evoking the spirit and the unique qualities of each bird, among them the kingfisher, nightingale, nightjar, song thrush, tern, tawny owl and puffin. Macfarlane narrates the bird entries, which also include the avocet, which “[when] seen at sunset in silhouette seems blown from glass – as if breath of wind would leave her in shards amid the sea reeds, the fescue, the eelgrass”.…