pollen color and winter 2020-2021

Here I'm using Growing Degree Days (GDD) to compare this Atlanta winter with previous winters. I calculated GDD using a web based calculator.  As seen in the table, this winter's GDD are much smaller than last year, with the nearest similar winter GDD found in 2013-2014. 

The back yard bees currently return with bright orange pollen and infrequently return with grey pollen - click on the image to enlarge. I'm using a wiki page of pollen colors of plants in hardiness zone 5, while Atlanta is found in plant hardiness zone 7 which presents challenges when comparing:

• plant flowering dates
• matching pollen color with a limited number of trees and plants
  

Other than color, I'm not able to analyze the bright orange pollen, but it's most likely sourced from winter-flowering ornamental cherry trees blooming in the neighborhood and attracting honey bees.

Using binoculars, I see that red maple trees are not yet flowering.  With evidence from previous years, I'll guesstimate that rosemary is the source of the grey pollen.