Which types of crow?

Hello everyone,

I’m occasionally on posting about my rook with the wonky leg (Mori) however she has been joined in the last 6 months by these pair - my kids have named them Russell and Silver. They appear to be a bonded pair, one is never there without the other. Russell (the darker one) is the bravest and has become very friendly, Silver is far more shy but is growing in confidence. 

Can anyone tell me what type of crow they are?

I forgot to mention that Mori the rook tolerates Russell but fights with Silver so I’ve moved Mori’s feeding station closer to me to resolve the bickering! 

Thanks!