These little birds come to New Jersey for the winter and leave in the spring, as described in this article. They are very attractive, with their flashing white tail feathers when they fly and their twittering calls.
A Ruby-Crowned Kinglet also visited, on its migratory flight to the South.
We used to see a lot more Fall migratory warblers and such on Block 832 until a neighbor cut down most of the trees in his yard. If you spend time outside at this time of year, look up and you may spot these tiny visitors in the treetops. But don't expect to be able to tell them apart easily. There is a reason why they are known as Confusing Fall Warblers.