As Venatic pointed out, there are different species of crows and they do sound a bit different.
Crows in other countries sound similar to ours, yet distinctly different, as well as in appearance.
Here's a South African Crow Shoot I videoed in 2007 near Cape Town. The calls (Foxpro and mouth calls)
are the typical sounds, yet the pied crows responded just the same, even though they have a different voice somewhat.
