Scientific precision adds additional shades to vivid poetic description in this beautiful but unsettling workAccording to one of its several traditions, St Valentine's Day is the wedding day of the birds. Chaucer refers to it in his poem, Parliament of Fowls, composed in honour of the marriage of Richard II and Anne of Bohemia: "For this was on Seynte Valentyne's day/ When every fowl cometh there to choose his mate." Despite Chaucer's masculine pronoun, it's well-known that, in the bird kingdom as well as elsewhere, the hens usually make such important decisions, and their judgement, with good evolutionary reason, is based on looks. This week's poem, "The Coloration of Feathers" by Ruth Fainlight isn't a love poem nor a study ...