Both tan and white morph White-throated Sparrows visiting my yard

Earlier this past week I was delighted to find my first yard bird White-throated Sparrow species and not just one but two. And to top that off, one was a white morph and the other a tan morph. I learned from some research I did that birds of this species typical mate with a bird of the opposite morph-that is called "negative assortative (disassortative) mating" according to Birds of North America online.

While this species is known to use urban areas during migration and to come to feeders, I only observed them using my bird bath--and they used it often but only for drinking when I was observing. I do have feeders that they may have fed from or beneath when I was not observing. I found them by hearing their 'seep' calls, used for contact, which were different from birds I was familiar with-and while they were hear they gave the seep call often. They stuck together, coming to the bird bath together and perched in a large shrub near each other. Since this seems late for them to be migrating I hoped they might decide to winter in my yard but I watched them fly off at dark earlier this week and have not seen them again. SeEtta