tl;dr: Neuroscientists at Baycrest Academy found that expert birdwatchers' brains are structurally different from novices', with more activity and better-preserved organization in regions tied to attention and visual recognition — suggesting birdwatching may slow age-related cognitive decline via neuroplasticity. Separate research in German nursing homes showed that installing bird feeders improved residents' cognition, mobility, and wellbeing within weeks, prompting insurers to fund the setup in 400+ facilities. Similar therapy programs are now used for dementia patients and stroke survivors with aphasia in the US and UK.