They don't sound Siberian to me. What a rip-off.
By the way, I'm sure that those popularity bars are absolute nonsense. Search for Neko Case and there is zero popularity on all her tracks except one. Her name gets 1.3 million Google hits, while "Siberian Chipmonks" + "Sing the charts" gets 2,000. I don't see how they can be infinitely more popular than a lass who gets reviewed in the Grauniad.
Hahaha... I just f*ckin love this blog, congrats, mate! I came across it by chance, but from then on a visit from time to time is a must.