Listen to DNR avian biologist Kim Grveles from the May 20, 2012 Larry Meiller Show.
Photo Credit: Joel Trick, USFWS
Volunteer Ron Refsnider is the May 2012 comeback champ for his work to capture and band Kirtland's Warblers in Wisconsin since DNR's program started in 2008. Refsnider, a retired U.S. Fish & Wildlife Service biologist, had worked on Kirtland's warbler conservation in Michigan in the 1990s. He donated the equipment, his time and expertise to mark the birds for study. His banding makes it possible for DNR to track the movements of males, to define their territories, to document their nesting outcomes, and to measure their population growth.
A decade ago, a female Kirtland's warbler was the holy grail for Wisconsin birders: everyone wanted to be the first to see one or to confirm the bird's breeding in Wisconsin. The federally endangered species had almost exclusively nested in Michigan's Lower Peninsula, but started expanding its range and Wisconsin had prime habitat.
In 2007, Dean DiTomasso was in the right place at the right time. Read about his discovery and what happened next.
"A warble from the barrens," April 2009, Wisconsin Natural Resources magazine.
To help increase and manage Kirtland's warblers and their habitat in Wisconsin, DNR, the U.S. Fish & Wildlife Service and other partners now conduct annual surveys to listen and look for the birds, monitor nests in Adams County where breeding sites have been found, and set traps to keep cowbirds away from the warblers' nests.
They also are working to maintain and expand the mix of 5- to 20-year-old jack pine trees and barrens to provide quality habitat for Kirtland's warblers and other species.
Numbers of Kirtland's warblers in Wisconsin are still quite small. The Natural Resources Board has approved listing the bird as a state endangered species, increasing protections and awareness of the species and its needs.
Scientific name: (Dendroica kirtlandii):
A small songbird that measures 5 ½ inches long and weighs under a half ounce.
The male has a bluish-gray back, black streaks on its yellow breast, and black eye lines and a black patch that make it look like it's wearing a mask. Females are less showy; they are brownish with faint streaks on their pale yellow breast.
Habits and habitats:
Kirtland's warblers nest only on the ground near the lower branches and in large stands of young jack pines 5 to 20 feet tall and 6 to 22 years old. The tree's age is crucial, although biologists are not sure why. It's possible the birds need low branches to help conceal their nests.
Until 1995, their breeding range was almost exclusively in Michigan's northern Lower Peninsula. It has since expanded to Michigan's Upper Peninsula, Wisconsin and Ontario. The birds winter in the Bahamas. In Wisconsin, Kirtland's warblers have been observed in several counties and nests are confirmed in Adams and Marinette counties.
They are Insectivores, gathering food mainly by gleaning among pine needles, leaves of deciduous trees, and ground vegetation. Sometimes they hover to snatch flying insects.
Brown-headed cowbirds are a big threat to Kirtland's warblers. Known as a brood parasite, the cowbird lays its eggs in the Kirtland's nest, where the unsuspecting mother incubates and feeds the young. The cowbird, which hatches a day earlier than the warblers, is bigger and able to claim more food than its nestmates.
Wisconsin records a significant milestone in 2013 as the first bird hatched and banded in Adams County returns to the area.
Read weekly updates about Kirtland's warblers in Wisconsin