defrost • yesterday at 9:52 AM

The BBC article is perhaps truer to the paper:

  Erik Wing, who led this research at Baycrest Academy for Research and Education in Toronto, Canada, compared MRI brain scans from bird experts to those of novices while they identified birds. He found that expert brains were wired differently in regions important for functions like attention, visual perception and visual recognition. 

The study only (?) looked at the brains of birdwatchers, the paper extrapolates the study to make assertions about the brains of active subject experts in general.