Population of endangered Great Lakes bird remains stable

Michigan officials listened to the sweet songs of Kirtland’s warblers throughout the state in June — and the chorus was a positive one.

Kirtland’s warbler. Photo: U.S. Fish and Wildlife Service

The population of the endangered birds remains steady, according to the annual survey by the Michigan Department of Natural Resources and the Environment.

Officials surveyed in mid-June when the birds defend their nesting territories.  Birds are detected by listening for their songs — as their singing can be heard for up to a quarter mile.  Since only males are belting out songs, populations are estimated by doubling the number of singers

The 2011 survey documented 1,805 singing males, which is approximately what the population has been in recent years.  The bird made a strong comeback after singing male populations hit a low in 1974 and 1987, when only 167  were observed.

Singing male populations in Michigan. Photo: Michigan Department of Natural Resources.

Warblers nest on the ground in Michigan, Wisconsin and Ontario —but most prominently in northern Michigan’s jack pine forests.  The population declined rapidly as modern fire suppression stopped the natural wildfires that provided the barren landscape and young jack pines that warblers love to nest in.

State and federal officials now harvest and replant approximately 3,000 acres of jack pine trees a year to mimic natural processes.  Large prescribed burns aren’t safe or economical in northern Michigan, according to the state officials.

And it seems to be working.  Or maybe it’s the eight-month Bahamas vacation the birds take every year.  Either way, the warbler song was again strong in Michigan this summer.