A few years ago in April/May of 2017 I saw a loon in this lake in Maryland looked perfectly fine and it was a very recognizable bird with its black and white pattern. I visit this lake frequently and in June and July of that year, I saw that the loon was still there. It has me confused that it didn’t migrate north in the spring and stayed throughout the summer. I have seen similar cases both online and outdoors.
A similar case occurred in July of 2021 when a dark-eyed junco visited my bird feeders for a few days. I have no idea why it just randomly showed up and it too looked perfectly fine.
Lastly, the most common example of this lingering is ring-billed gulls showing up around my local shopping and garden centers in June and July after I read that their range in Maryland is blue (winter).
For a long time I’ve been trying to figure out the answer and this forum seems like the best option to ask the question: Why do some birds who are supposed to spend the winter in a certain area/region stay there for a long time?
Common Loons typically don’t establish a breeding territory until they are a few years old. Young birds stay farther south during the breeding season, typically not returning north until their 3rd year.
This is probably just a case of mild vagrancy. Maryland is just east of their breeding range in Appalachia.
Ring-billed Gulls take 3 years to reach adulthood. Immature/juvenile birds regularly winter as far south as Florida in the eastern U.S.
Comment to add, this is a common misnomer in print field guides. For example, both my Sibley and Peterson field guides label blue as the winter range. That’s fine for most songbirds, but as your examples illustrate, it’s typically not really correct for waterbirds that take multiple years to reach maturity. All the Cornell Lab applications label blue as the nonbreeding range which is a more accurate representation.
