There’s actually a brood every year (except years that are missing), but each brood is separate. So the ones out this year are the children of the ones that were out 17 years ago. The young of the 2004 group are still underground.
Each brood also occurs in a geographically limited area, which can vary even by neighborhood. We haven’t seen any this year in my neighborhood in Silver Spring, either, but I have friends in Alexandria who have tons of them.
There’s actually a brood every year (except years that are missing), but each brood is separate. So the ones out this year are the children of the ones that were out 17 years ago. The young of the 2004 group are still underground.
Each brood also occurs in a geographically limited area, which can vary even by neighborhood. We haven’t seen any this year in my neighborhood in Silver Spring, either, but I have friends in Alexandria who have tons of them.