I wish I could adequately capture an image of the numbers of Rosy-Finches that visit my yard. It's got to be well past 200 now, and they visit every single time it snows.
The other day, we got less than an inch of snow, but the Rosies came. Sure, they only stayed a couple hours in the morning...but they showed; like clockwork.
I have read that during breeding season these birds develop a special 'pocket' where they can store extra food. In the high places of the tundra where they breed, they must search far and wide; going great distances, to and fro, looking for food. But apparently those pockets are not 'year 'round' attributes.
Still, it seems they may come a distance as they seldom arrive all that early here...perhaps an hour after daylight. And they don't stay nearly as long as the Juncos, who will feed till nearly dark.
I have also read that, because of their limited exposure to people on their breeding grounds, they are fairly comfortable with people in close proximity. I've noticed that while I'm tossing seed or re-filling feeders, they will land within a step or two of where I'm standing. If I quit moving, they will land by the hundreds; feeding right in front of me.
It is the most astounding sound when they all take off at once. I wonder where they go at night.