I’m concerned about this. Are you? Why or why not? Depending on the findings of the coming study (described below), what prospects for species recovery strategies do we have?
There is something about the migrants’ lifestyle that is making them vulnerable and their declines are reminiscent of those we began to see in farmland birds 30 years ago. Migrants have been slipping away for more than three decades but the scale of their disappearance is only now becoming apparent.
Mystery is surrounding the huge declines of birds that migrate thousands of miles from Africa to Europe each spring.
Scientists fear that their dwindling numbers may be a warning of widespread environmental damage. Climate change, drought and desertification in Africa, and massive pesticide use on African farmland may all be to blame for the declines of once common UK birds such as the Spotted Flycatcher Muscicapa striata, Northern Wheatear Oenanthe oenanthe, Wood Warbler Phylloscopus sibilatrix and European Turtle-dove Streptopelia turtur, a BirdLife Europe-wide study led by the RSPB (BirdLife in the UK) concludes.
The research, to be published in the journal Biological Conservation, shows that 54 per cent of the 121 long-distance migrants studied have declined or become extinct in many parts of Europe since 1970. The study also compared migrants and resident birds with similar characteristics, and in almost every case, the migrant fared worse.
The possible reasons being explored:
Climate change: air temperatures are changing and warmer springs are causing insects to breed earlier. Resident birds may be surviving winters better and, alongside insects, are adapting more quickly to climate change. Long-distance migrants flying from Africa cannot detect the temperature increase that heralds an early spring in Europe and may arrive too late to use the best nest sites and catch the insect food glut on which their young depend.
Drought and agriculture in the Sahel: the Sahel borders the southern Sahara, stretching from the Atlantic Ocean in the west to the Horn of Africa in the east. It covers 1.6 billion hectares and includes regions of 12 countries. Long term drought and agricultural intensification, including the widespread use of pesticides and fertilisers, has turned much of the Sahel into desert. The area is the first feeding opportunity for migrants crossing the Sahara.
Desertification: the Sahara is now much bigger than it used to be, also because of drought. Migrating birds must fly over this desert in one flight, to reach their winter homes. The birds may be unable to fly further in one go and if so, many will not cope with the longer journey.
Pest control: huge amounts of pesticides are now used to kill locusts and protect crops in Africa, and may be killing birds as well.
The concluding paragraphs of the BirdLife International piece describe a silver lining, through an environmental education campaign to raise awareness of migrants among children throughout Europe and collect more data about the timing of migration. The initiative, Spring Alive, allows people to record their first sightings of migrants online, and then combine them with thousands of others to produce maps showing the advance of spring.