There is a great article over at Wild Birds Unlimited about why (and if) Juncos return to the same feeders year after year. You can read it here:
“Birds are one of the freest creatures on the planet, able to fly anywhere at anytime with nothing to bind them to any single location. And yet birds, like humans, are creatures of habit and bird banding studies have shown that many of our winter birds, such as Dark-eyed Juncos and native sparrows, utilize the same wintering location year after year.
With a potential lifespan of over 10 years, it is likely that the Junco gleaning millet off of the ground below one of your feeders has spent many previous winters as your loyal backyard guest. And recent research shows, that is only half the story!
These birds are not only loyal to a specific location, but also to a single feeder! The study showed that the only time they abandoned their favorite feeder was during periods of cold weather when the feeder was placed in a location too exposed to the wind.”