Wisconsin Kirtland's Warbler Update May 31, 2010

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Bander, Ron Refsnider, removes a captured Kirtland's warbler from the mist net.

Photo by USFWS: Joel Trick

More Arrivals

There has been a lot of activity at our Adams County nesting area over the past week. Nick has observed an increasing number of unbanded birds, and until all were color banded, it was difficult to know how many were actually present. On Thursday, we captured and banded all of the unbanded males at the site. As of Saturday the 29th, at least 16 male Kirtland’s warblers were present at the Adams County breeding site where birds have been known to nest since 2007. This total does not include two birds observed at the site earlier this year: a color banded bird which nested here in 2009, and a mystery bird which had a single aluminum band. Both of these birds are no longer present and have apparently moved on. Perhaps these two birds will be discovered at another site nearby, when our second warbler monitor Paul Schilke begins work this week. We plan to employ Paul to check many other seemingly suitable sites in Adams County that we have not yet had time to survey, as well as sites in Marinette County.

 

Also this week, Paul Charland and Rachel Samerdyke of USFWS reported the return of a banded bird to the other Adams County nesting area where it successfully nested in 2009. We will ask Paul Schilke to monitor this site as well, as it may attract more birds before the year is over.

 

Measuring tail length of color-banded male Kirtland's warbler.

Photo by USFWS: Joel Trick

Color Banding

We kicked off our 2010 banding efforts on Thursday May 27, with the arrival of our volunteer bander Ron Refsnider. Nick was able to guide us to the territories of each of the 8 unbanded males that he had identified over the past several weeks. By the end of a long and hot day, we had successfully captured and banded all 8 birds. Having these birds marked with their own color bands will allow Nick to more effectively map their individual territories and greatly facilitate monitoring.

 

We also attempted to recapture the banded male that has apparently lost one of its color bands. Despite several efforts and the bird spending extensive time near our net, he was just too savvy and refused to be caught. We hope to try for this bird again during a future banding trip, as we would very much like to confirm his identity. We are 99% sure he is the same bird that occupied this territory last year, but would like to capture him and check his band number. If in fact this is our banded bird from 2009, it means that we have had 100% survival of Adams County banded males over the past year.

 

We considered traveling to northern Marinette County to make a try for a single bird reported at the site where a pair nested in 2009, but decided to hold off for now and see if any more reports came in. We did not have to wait long, as just in the past few days we received word of another male at a site where birds have been seen each of the past two years. Yesterday we received a report of two birds at another site in southern Marinette County. We are planning a trip to capture and band all of these birds next week.

 

Color-banded male Kirtland's warbler ready for release.

Photo by USFWS: Joel Trick

Nesting Season

This week saw the arrival of more female Kirtland’s warblers, and most immediately began building nests. So far, Nick has been able to confirm the presence of at least six females and four nests, with several eggs in at least one of the nests. We expect more females and nests to be found in the next week or so.

 

Summary

So far this year, we have confirmed at least 19 different male Kirtland’s warblers in Adams County, and at least 6 females. Volunteer surveyors Jack Swelstad, John Probst and Jon Motquin have also reported four males at three different sites in Marinette County. This is by far the highest number of Kirtland’s warblers ever reported in Wisconsin in any year.

 

Cowbird Trapping

USDA Wildlife Specialist Barry Benson reports that over the past week, he removed an additional 22 cowbirds from the three cowbird traps. Through May 28, a total of 189 cowbirds have been captured and removed from the traps at the Adams County Kirtland’s warbler site.

 

 

 

Joel A. Trick U.S. Fish & Wildlife Service 2661 Scott Tower Drive New Franken, WI 54229 920-866-1737 joel_trick@fws.gov

Kim Grveles Wisconsin Department of Natural Resources 101 S. Webster Street - ER/6 Madison, WI 53703 608-264-8594 kim.grveles@wisconsin.gov

 

 

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