Kirtland's Warblers found nesting outside Michigan.

The article presents information on Kirtland's Warbler, North America's most endangered wood-warbler. For years its core breeding range was limited to a handful of counties in northern Lower Michigan, but the warbler's population has grown rapidly since 1990. In 2007, census-takers counted 1,697 warblers in Michigan, 8 in Wisconsin, and 2 in Ontario. A total of 1,486 warblers were counted in 2006, and 1,415 the year before that.