We've had an outbreak of Dickcissels in Ohio, but this is much better than, say, an outbreak of acne. Dickcissels are charming little cardinalids of the Great Plains and midwestern prairie regions, and Ohio gets very few some years. In boom years, we get lots. The proper term for such boom and bust cycles is cyclically irruptive.
Birds of North America online series of monographs, Ohio lies on the far eastern cusp of this species' range. That map is actually a pretty good rendition of the distribution of the tallgrass prairie, most of which has been destroyed and of which the Dickcissel is a resident. Fortunately, this songbird has adapted and now does fairly well in a variety of agricultural situations and reverting meadows and fields.
Check its winter range. Dickcissels really get into the deep south, and the majority of the populations winters in a very small region in northern South America, primarily in Venezuela. There, they mass into roosts that can number into the millions and foraging birds radiate out into grain fields during the day. They can cause crop damage, and there have been instances of mass poisoning in an effort to rid fields of what are likely regarded as feathered locusts by some agriculturists.