The nightingale makes an epic journey from sub-Saharan Africa to breed in Europe each summer but there are barely 7,000 nesting pairs left in England. Spanish researchers examining wing sizes of two nightingale populations in central Spain have found that the average wing length relative to their body size has fallen over the past two decades. Shorter-winged birds were found to be less likely to return to their breeding grounds after their first trip to Africa. According to a new study published in The Auk: Ornithological Advances, natural selection driven by climate change is causing the birds to evolve with shorter wings. Scientists believe that there is a suite of adaptations that make the nightingales effective migratory birds including a long wingspan, a larger clutch size and a shorter lifespan, which are controlled by a set of linked genes. This means that selective pressure on one trait also affects the other features.
SOURCE: THE GUARDIAN