Birds have accents, or at least their calls and songs vary by region. They're generally recognisable as being similar but sometimes it can be confusing. Throw in species like starlings or bluethroats (Luscinia svecica) which are accomplished mimics and life gets complicated.

Still, it's a great idea. Just listening to a blackbird (Turdus merula) or song thrush (Turdus philomelos) singing on a nice Spring evening is life-affirming all by itself.