Garden Birds Evolve Longer Beaks to Use Garden Feeders
Between 1970 and the present day the beaks of British birds have grown longer. Scientists have been researching why the birds have evolved so quickly and whether the phenomenon is confined to Britain.
Scientists looked at birds in Britain and the Netherlands. DNA was taken from more than 3,000 great tits in Wytham Woods together with Oosterhout and Veluwe in the Netherlands. The genetic differences between birds from the two countries were explored. It transpired that there were changes in the gene sequences of British birds relating to face shape.
Researchers found that birds with genetic variants for longer beaks were more frequent visitors to feeders than birds without the genetic variation. The birds with longer beaks were discovered to be more successful breeders than the other birds in the UK but this was not the case in the Netherlands. The scientists are, therefore, certain that British birds have evolved longer beaks due to the prevalence of garden in this country.
The beaks of the British birds were 0.3mm longer than those of their European counterparts. This doesn’t sound like a huge difference but even a small advantage could improve a bird’s chances of survival.
If birds with longer beaks have a greater rate of survival it is these birds which live long enough to breed and pass on their genes.
More Birds are Visiting Feeders
Although the recent research involved studying only great tits it is likely that other species have experienced similar changes. Back in the 1980s only 18 species of bird had been recorded feeding on seed in gardens but that number has now risen to 130. Farmland birds which have suffered habitat loss are increasingly looking for food in urban gardens during the winter months.
"Between the 1970s and the present day, beak length has got longer among the British birds. That’s a really short time period in which to see this sort of difference emerging," said study co-author Jon Slate, professor in the department of animal and plant sciences at the University of Sheffield.
The increase in beak length is the result of genetic changes caused by natural selection. The findings mirror those of Charles Darwin whose studied finches and proposed that that they evolved physical traits which helped them to adapt to different environments in the wild.
The research was carried out by scientists from the Universities of Oxford, Sheffield and East Anglia in conjunction with experts from the Netherlands.
British Bird Feeders
Householders in the UK spend around twice as much on feeders and bird food than people in mainland Europe and have been doing so for many years. It isn’t yet possible to prove that feeders are behind the increase in beak length but feeders are the likely explanation.
This is an extraordinary example of rapid evolution and it is amazing to think that garden bird feeders could have altered the course of evolution in such a short space of time.