As it's been around 7 years that I'd been visiting the local Downtown Los Angeles pigeon flocks and keeping this blog, several breeding seasons had come to pass, with some distinctions in the subsequent offspring of the pigeons that had been living back then now prominently mixing in to the general showing of the birds (I estimate that the local flocks' birds will see an average lifespan of up to 10-15 years, since they're cared for, on a distributed and daily basis).
What does this mean?
It means that the pre-existing birds (adults and wild pigeons) are seen, side-by-side, demonstrating what the University of Utah's Pigeonetics website documents as genetic variations, due to some or other particular conditions; genetic development conditions, as it were.
The University's website does a fine and entertaining quick read on genetic variants, as well as some of the conditions under which some of these variations occur, in the birds' pedigrees. Some of the conditions require multiple breeding seasons, as well as chance and distributed mating efforts - keep in mind, pigeons are bound to relatively simple behaviors, given that their outdoor wildlife hobbyist environments are coupled with some challenges and strife, from naysayers to their well-being. This being the case, 7 years is plenty of time for these birds to have mixed, and - one can observe, on any given day, the richness in variety that the birds' plumage and other ornamentation, such as their eyelids, leg feathers (my mother would call this feature their "pants"), as well as frills and beak shape and size differentiations. Check out the University of Utah's site, as the information there will assist most readers in understanding the sort of information discussed here, in a more pragmatic and straightforward manner of explanation, as it was the source of my realization of the developments discussed here, and there are simple, page-by-page discussions that are navigable, with pictures and or charts included on each page. It's really a well-done explainer site, that serves the purpose of demystifying some of the complexities of pigeon pedigree development and establishment.