At least five male Kirtland's Warblers have returned to the site in Adams County, in central Wisconsin, where nesting has occurred each of the past two years, according to biologists Joel Trick of the U.S. Fish and Wildlife Service and Kim Grveles of the state's Department of Natural Resources.
They say the first birds were spotted Tuesday, May 12, by Nick Anich, this season's Kirtland's Warbler monitor. Birds were not seen the day before. "Given that there was heavy migration at many Wisconsin sites on Monday night, we believe that we may have detected the Wisconsin arrival date of the species," Trick and Grveles report.
Four of the endangered warblers are wearing leg bands. One of them (shown at right), banded in the Bahamas on March 20, 2008, has returned to Wisconsin for the second year in a row. It attended two nests last year, one of which fledged cowbirds and the other of which apparently failed.
Two of the other banded males (and their mates) each fledged five chicks last summer. At least one unbanded male is also present.
In addition, the biologists say that a single male has returned to Marinette County in northeastern Wisconsin, where a male and female were observed in 2008.
Traps for Brown-headed Cowbirds, which threaten Kirtland's Warblers by laying eggs in their nests, have been in place since April 22, and so far, 198 cowbirds have been trapped and euthanized. Trapping will continue through mid-June.
"We plan to again capture and place color bands on all Kirtland’s Warbler males that we encounter," say Trick and Grveles. Ron Refsnider, our volunteer bander, will lead our banding efforts. We will commence banding operations around May 25, assuming that there are enough unbanded birds to justify our mobilization at that time." -- M.M.
For our previous news reports on the expanding breeding range of Kirtland's Warbler, follow these links:
Kirtland's Warblers found nesting outside Michigan, "Birding Briefs," October 2007.
Kirtland's Warblers nest in Ontario, "Birding Briefs," February 2008.
Kirtland's Warblers breed outside Michigan again, "Birding Briefs," October 2008.
And if you can't get enough Kirtland's, here's more:
See the Kirtland's Warbler on our October 2007 cover.
Columnist Paul Kerlinger wonders if navigation errors are causing the Kirtland's Warbler to expand its breeding range, "On the Move," June 2007.
Columnist Pete Dunne describes how he and his wife conquered frustration and found happiness in the presence of North America's rarest bird, "Birder at Large," June 2005.
Photo: A male Kirtland's Warbler sings from a perch in Adams County, Wisconsin, on June 7, 2008. Ornithologists on the island of Eleuthera in the Bahamas banded it on March 20, 2008. Photo by Joel Trick, U.S. Fish and Wildlife Service.