Something may have happened to the swan's original mate, but he/she is still returning to the same spot for this year's nesting season, or it is a juvenile swan that is trying to establish a habitat for itself. In any case, the swan is probably not confused, just looking for a nesting site for the upcoming season and hopefully, finding a mate that will find the same area.

Note: Maryland DNR along with other state and federal wildlife officials have been killing Mute Swans for years trying to eradicate them from their habitats so that the larger Trumpeter Swans (which are not native to to the Maryland area) can be introduced for Trophy Waterfowl hunting purposes. So, your original swan and nest may have been disturbed or killed so that they will not return to your area. The Regal Swan