I found out juncos love petunia seeds by accident. They love them so much they will fly up to the flowerpots on your deck and peck away at the little dried seedpods for hours and days on end.
One Autumn, when I was supposed to empty out the flowerpots and tidy up a bit for the coming winter, I didn't. I forgot about the pots and just left them sit on the deck, all weedy and dead, which was the best thing I could have done -- for my juncos, and for my family, because now we get to watch them peck and pick and forage in the brown, withered vines of the long-dead plants all winter.
The first winter I witnessed this, I thought it was an anomaly, but it’s not. They returned the next year for more of the magic seeds. Now I have pots on my deck and pots on the ground, and I also plant them around the back yard too. Our junkies enjoy popping up and nipping at the seeds for a good part of winter. They usually start munching about mid-January, and true to form, today when I came home from work, three were on the deck foraging in the pots. The seeds are so tiny, I don’t know how they even find them, but they do and they love them.