Wednesday, 25 March 2009

Listening out for cuckoos this April?

This is a quick post to link to a great article by Mike McCarthy in The Independent about the disappearance of the cuckoo and other summer migrants from our woods in spring and summer. According to surveys by the British Trust for Ornithology and the Royal Society for the Protection of Birds between 1994 and 2007, 37 per cent of our cuckoos disappeared. Add to this:
41 per cent of our swifts
47 per cent of our yellow wagtails
54 per cent of our pied flycatchers
59 per cent of our spotted flycatchers
60 per cent of our nightingales
66 per cent of our turtle doves
67 per cent of our wood warblers
All these birds are summer visitors and their problems seem to be caused by two major factors: pesticide use is causing huge declines in insect numbers along their migration routes while climate change is bringing insects out earlier so the birds are not in the right places to eat them at the right times, i.e. the earth's meteorological and ecological rhythms are shifting out of balance. 

McCarthy points out the cultural role these birds have played in England, something I'm often reminded of as when asked about my research area about one in three people respond to hearing I work on medieval song by saying, 'Oh, like 'Sumer is icumen in''. As is obviously well known this thirteenth-century song welcomes spring with the cuckoo's song and other natural raucousness:

Sumer is icumen in,
Lhude sing cuccu!
Groweth sed and bloweþ med
And springeth þe wode nu,
Sing cuccu!
Awe bleteth after lomb,
Lhouþ after calue cu.
Bulluc sterteth, bucke uerteth,
Murie sing cuccu!
Cuccu, cuccu, wel singes þu cuccu;
Ne swik thu nauer nu.
Sing cuccu nu. Sing cuccu.
Sing cuccu. Sing cuccu nu!

McCarthy concludes: 'here we have one of the world's profoundest motions, a living announcement of spring, coming to an end. We have grown used to wildlife losses, but it will be far more than the loss of a species to say goodbye to the cuckoo, and to bid farewell to its fellow summer visitors, as we are now on course to do sooner rather than later. It will be something so momentous in its implications that perhaps it is better not to think it through.'

I expect, however, he does want us to think through those implications.


  1. Thanks for the post. Do you know of any examples where birds have started adapting to the changes that you mention - such as the insects coming out earlier?

  2. Thanks! The classic example is that swallows are arriving earlier with the warmer springs. But most animal/plant adaptation rates can't keep pace with the rates of change global warming introduces and some things are especially difficult to adapt to (like the barrier formed by the growing Sahara or - off topic - ocean acidification).