IT HAS TAKEN NEARLY 150 years to work out the missing link in Darwin’s theory of evolution. Natural selection has always been recognised as a fact, even by ardent Creationists. It’s how the teeming diversity of life arises in the first place that is the puzzle. How, in the time available, could random mutation alone generate anything as complex and co-ordinated as an eye? Marc W. Kirschner and John C. Gerhart — Nobel-bound, I suspect — have a startling answer. It’s not blind chance or Intelligent Design that invents new forms but us.

In The Plausibility of Life (Yale University Press £18.95; offer £17.05) they outline their theory of “facilitated variation” and describe how an organism “participates in its own evolution”, recycling and rearranging chemical units and processes to translate genetic mutations into viable creatures. It’s not an easy book, but heartening to find that, at the most basic molecular level, life’s inventive progress is managed by a kind of grassroots democracy.

In the light of this, Mark Carwardine’s catalogue of superlatives, Extreme Nature (Collins £30; offer £27) seems a tad elitist. His tributes to the Most Elastic Animal and Most Extreme Sex Act rather denigrate the honest achievements of the averagely stiff animal. Still, it’s a witty celebration of the variety of life, and reassuring to know that life has evolved a creature capable of drinking five times its body weight (the broad-tailed hummingbird).

The real puzzle with birds is their songs. If they are just functional messages, why are they so elaborate? Why do they move us? In Why Birds Sing (Basic Books £16.99; offer £15.29) David Rothenberg darts from brain-wiring to Romantic poetry via Mozart’s pet starling (which propelled a tune from the G major piano concerto two centuries forward by putting in a G sharp).

Rothenberg has always been a sparkling ecological thinker, and maybe just as importantly, a demon jazz clarinettist. The book begins with him jamming with a white-crested laughing thrush in the Pittsburgh Aviary and ends with a duet with an Albert’s lyre-bird, which takes six years to learn its astonishing medley of the songs of all the other forest birds.

Rothenberg’s conclusion — busked more than argued — is that birdsong isn’t so much a referential language as true music, its beauty lying partly in pure maths and partly in emotional expressiveness.

Some biologists believe that our fascination with birds — fast becoming a worldwide love affair — stems from that ancient bit of our brain that’s still up there crooning in the tree-tops. The haunting images in Paula Henderson and Adam Mornement’s Treehouses (Frances Lincoln £25; offer £22.50) are like half-remembered dreams. Californian Portaledges, ancient Iranian summerhouses, eco-warriors’ stake-outs, all seem part nest, part spacecraft. Perhaps John Prescott should look at them.

The originality of Ian Collins’s delicious Making Waves: Artists in Southwold (Black Dog £30; offer £27) is that it is rooted in the life of a real community, not the abstractions of formal art history. A daunting range of artists — Philip Wilson Steer, Stanley Spencer, John Piper — were drawn to the Suffolk seaside town, and relished not just its Adnam’s pubs, beach huts and spare shoreline landscapes, but each other. The connections are as remarkable as any in the carnival of evolution: for instance, the teenage Damien Hirst was inspired on a day-trip by Francis Davison and Margaret Mellis’s driftwood collages.

Jacqueline Simpson and Jennifer Westwood’s immense and enthralling The Lore of the Land (Penguin £30; offer £26.99) is also firmly rooted in place, but its no-nonsense accounts of English legends and folk tales have an anthropologist’s sense of pattern: the North Country’s monstrous Jinny Greenteeth — a “water bugbear” designed to frighten children from water, for instance, reappears in the mermaids of eastern England. But these tales are so exactly located, that they get personal. I was delighted to find Peter the Wild Boy, the 18th-century Hertfordshire feral child whose collar hung in our school library and whom we hero-worshipped, but was oddly troubled to learn that he had “escaped” to Norfolk.

Making something universal out of the local is a mark of great country writing. The final volume in Ronald Blythe’s classic Wormingford Trilogy, Borderland (Black Dog £16.95; offer £15.26) continues this collection of weekly journals, written in sublime English, and making thinking, gardening, writing, preaching, conversing with other creatures, seem part of a seamless life. On the shortest day, he is up before dawn, watching through the windows of the painter John Nash’s old house, the world begin to take shape. Facilitated variation indeed.

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