Sunflower Seed Color Variation

My mom gave me some sunflower plants earlier in the year, and the ones I planted outside my kitchen window, on the South side of the house, did quite well.  I got three large flowers, and amazingly, this is the first year the squirrel didn't completely strip the seeds while they were still white.  So I just picked them about a week or so ago, since we had some frosty nights already in Vancouver.

Here are the flowers :

I found it very amusing that the color of the seeds from each of the flowers was very distinctive.  The one almost reddish, the second one very pale, and the other with the more characteristic black and white markings (except a bit pale since they were not fully developed) :

I would think my Mom got all the seeds from the same source, so I was amused to find such variation.