Why have great tits grown longer beaks? To crack the bird feeders!
THE beaks of British garden birds are getting longer to help them reach the seeds in bird feeders, according to scientists.
Leaving food out for birds to help them through the winter has become widespread in recent decades, and scientists believe great tits have developed longer beaks than their European counterparts as a result.
The beaks appear to have lengthened relatively quickly in evolutionary terms – since only the 1970s. This period has seen the rise of garden centres and programmes such as Springwatch, which have encouraged the practice of leaving food out for birds.
A research team analysed DNA from more than 3,000 British and Dutch great tits. After tagging the birds, they found those using feeders were most likely to have genes for longer beaks.
Co-author Dr Lewis Spurgin, from the University of East Anglia, said: ‘It may be the case that having a longer beak allows birds to reach into a feeder and access or break down large seeds, such as peanuts. It could also be that a larger beak is stronger and less likely to get damaged by the types of larger seeds people leave out.’
The study’s results follow a talk by biologist Simon Watt at Cheltenham Science Festival earlier this year, in which he said blackcap warblers may be developing longer, thinner beaks to reach seeds in feeders.
The British spend around twice as much on birdseed and birdfeeders than homeowners in mainland Europe.
Co-author Professor Jon Slate, from the University of Sheffield, said of the findings published in the journal Science: ‘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.’
Dr Spurgin added: ‘It seems reasonable to suggest that the longer beaks among British great tits may have evolved as a response to this supplementary feeding.’