Where have all the mockingbirds gone?

We've always had several-to-many mockingbirds about all summer here in Gloucester. There''s usually a couple of nights in late June or early July when we get one within earshot who sings all night -- practicing all the new songs it's learned, or something.

It occurred to me recently that I have not seen or heard a single mockingbird this summer.

So I have a question for other New England (or other Northeast) folks who are accustomed to seeing or hearing mockingbirds: have you seen or heard any this summer? Does anyone know anything about their apparent absence?