This winter, we’ve been blessed with an abundance of owls. In 2003, a veritable horde of Common Redpoll invaded the U.S. It seems that, every year, another bird species floods our forests and feeders, carried on the wings of an irruption. But what kind of bizarre volcano spits out birds?

Our birding word of the day is irruption, not eruption. An irruption, from the Latin -rupt (burst, break), is defined as a sudden violent entrance or a bursting in. It may also reference a sudden and violent inroad, or entrance of invaders. Now, we avian enthusiasts do not equate birds with barbarians. An irruption is used to describe a large incursion of birds of a single species into an area outside of their normal range. Although exciting to observers, these movements are usually driven by unstable weather conditions or lack of food, so be nice to the tourists. Note that the occasional stray visitor is not called an irrupter, but a vagrant.