On a trip to Acadia National Park, I photographed this unusual Dark-eyed Junco. It had a very distinct yellow belly and yellow up into the chest. I showed the photo to the Park Ornithologist, Seth Benz, and he had this to say about it.
“It is an oddly colored Dark-eyed Junco. The yellowish underside is unusual.
I don’t know of anyone marking juncos using picric acid (which turns white feathers yellow).
I’ve seen hairy woodpeckers with white underside turned yellow, which can happen during incubation of eggs.
I’ll share the photo around with some folks who may have other opinions or ideas”
Anyone else with opinions or ideas?
Organikos 
Lovely photographs!
Just saw one here in Nova Scotia
Hi Daniel…great! Keep calm, and keep birding! and stop by again soon.