Black and Blue, Grey and Purple, Red and Yellow

I guess the above could be the description of a bruised leg, or the colours of the birds I saw today.  Glad it was the birds and not the bruise.  In Dunedin Hammock Park yesterday that's all I saw.  Black and White Warblers, Blue-grey Gnatcatchers, red Northern Cardinals and Yellow-rumped Warblers.  And at the Dunedin Harbor, later on, Purple Martins.  I also saw a Bald Eagle in the Hammock Park.  Is bald a colour?