Posted: 21/11/2013 at 23:08
Yes, they will be the last to be touched - reds, oranges and yellows go first and fast.
The bit below is from the link and mentions your tree...
It is not just native species that produce fruit taken by birds. Introduced species and the cultivated varieties of native species may also produce suitable fruit. There has been a fair amount of debate over the different cultivars of some berry-producing shrubs (including those in the genus Sorbus) and how attractive they might be to birds. Since birds have been shown to use berry colour as an indicator of nutritive rewards, it seems sensible to assume that the differently-coloured varieties of these shrubs will differ in their attractiveness to birds.
Ornamental fruits whose colours are not widely replicated within native fruits (for example white – seen only on Mistletoe) may prove less attractive to birds. This could explain why white-berried forms of Sorbus remain on the tree for so long.