By Paul Homewood
No, it was not an April Fools story after all!
The nightingale was feted by John Keats as a “light-winged Dryad of the trees”. But the much-celebrated small bird with a beautiful song may be increasingly endangered because its wings are getting shorter.
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.
In recent decades, the timing of spring has shifted in central Spain and summer droughts have become longer and more intense, leaving the nightingales a shorter window in which to raise their young.
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.
If the pressure of drought is leading the most successful birds to lay smaller clutches of eggs, with fewer young to feed, then it could be causing these nightingales to also lose the other linked traits that make them such effective migrants. This is an example of “maladaptation” where species’ responses to cope with changing conditions end up causing them harm.
Details of the study are here.
According to the RSPB, nightingales have long been rare in England, but are much more common in southern Europe:
The nightingale is a secretive bird which likes nothing better than hiding in the middle of an impenetrable bush or thicket.
They are skulking and extremely local in their distribution in the UK, while in much of southern Europe they are common and more easily seen.
Distribution and range of nightingale
https://en.wikipedia.org/wiki/Common_nightingale
While the British population of nightingales has been declining since at least the 1960s because of habitat loss, the European breeding population is estimated at between 3.2 and 7 million pairs, giving it green conservation status (least concern). Furthermore according to Birdlife, the European population is stable.
This alone makes a nonsense of the Guardian’s claims that nightingales are at risk because of a “climate crisis”.
As for the specific claims about shorter springs and longer, drier summers, the nightingale’s widespread range, which encompasses all sorts of climates proves that the bird is fully capable of adapting to different weather patterns, which themselves change far more on an annual basis because of natural variation.
But I doubt whether the study would have been funded in the first place, if the purpose was not to blame climate change.
via NOT A LOT OF PEOPLE KNOW THAT
April 2, 2020 at 06:33AM
Iowa Climate Science Education 