Cicadas

While they arrive every 13 or 17 years, that doesn't mean they won't be seen in a particular state again before then.

(They made news in the Midwest in 2007.) That's because within the species there are different broods, each with a different timeline..

Source: http://abcnews.go.com/Technology/cicadas-2011-13-year-insects-make-noisy-arrival/story?id=13582545