sound - Colored noises: Stationary or non-stationary?

I know for sure that white noise is considered as a stationary sound, but is that true for the rest of them? http://en.wikipedia.org/wiki/Colors_of_noise Also, can we meet some of these sounds in nature? Is there any relation between these noises and noises that you can hear in a town(vehices,traffic,people chatting) or are these noises just an artificial invention?

Thanks in advance for your ideas and thoughts!:)