Depth of ash…or is that red?

[Johannes]

This is a feral pigeon I’ve seen a lot of. Always notice the beautiful ones that I’d like to take home.
I assume this is an ash of some sort. The depth and richness of red reminds me of the rufous modifiers in red agouti rabbit coat colour. Is this so in pigeons too?

[AdamArcher]

The pattern is "dark check" so there is more pigment, then the extra darkness is from the "dirty" modifier gene.