A Kirtland’s warbler is shown perched in a jack pine tree in Lower Michigan
by Kathleen Lavey
Forest Resources Division
Michigan Department of Natural Resources
The tiny, gray-and-yellow bird known as the Kirtland’s warbler is a lot of things.
First, it’s extremely rare, with only a few thousand of the birds alive anywhere – 95 percent of them in Michigan’s northern Lower Peninsula. A comparative handful of others are found in Wisconsin, Minnesota and Ontario.
Second, it’s a conservation success story, the first passerine (perching songbird) removed from the federal endangered species list in 2019, although it remains on Michigan’s threatened species list.
It’s also a life-list must for birdwatchers who flock to Michigan to see or hear the bird each season.
And the warbler is extremely picky about where it lives, nesting only on the ground under the sheltering branches of shrub-like, young jack pine trees.
Tall trees won’t cut it as condo space for this rare bird, which is why people may notice some large jack pine harvests in the northern Lower Peninsula this summer.
The warbler also needs lots of space. And nesting birds favor the edges of clearings.
This why the bird needs human help to survive and thrive into the future.
“Jack pine is a fire-dependent species, which means the cones need heat to open,” said Keith Kintigh, acting supervisor of the Planning and Adaptation Section for the Michigan Department of Natural Resources’ Wildlife Division. “Because we protect against wildfire to keep communities safe, the large-scale fires that historically created the habitat the birds need aren’t regularly happening.”
That leaves cutting and replanting as the best way to make sure warblers have the conditions and space they need to thrive.
“The DNR will plant 1 million to 1.5 million jack pines on 1,000 to 1,500 acres per year to create Kirtland’s warbler habitat,” said Jason Hartman, silviculturist for the DNR’s Forest Resources Division.
Combined, the DNR and the U.S. Department of Agriculture’s Forest Service contract for the harvest of about 2,000 to 3,000 acres per year to create young forest for the bird.
Most of those cuts are sized at 300 acres or more, since the warbler prefers to have room to roam. They will rarely nest in disturbed areas that are less than 80 acres.
Trees also are cut and planted into patterns that allow for many clearings that warblers prefer, a pattern known as the “opposing wave.” It’s sometimes also referred to fondly as “the warbler weave.”
The warbler’s story
The Kirtland’s warbler – about 5.5 inches from beak to tail – was first identified and named in, of all places, Ohio. In May of 1851, Jared Kirtland, a doctor and naturalist, spotted some birds as they passed through Ohio on their way to Michigan from their winter home in the Bahamas. He started the process to determine if the bird was separate and distinct from others in the wood warbler family.
Kirtland’s warblers eat insects and berries, and they incubate about four eggs each year.
Besides the loss of habitat and suppression of wildfire, the warbler population also shrank through the 1980s due to brown-headed cowbirds.
The cowbirds are called nest parasites because they lay their eggs in the nests of other birds, leaving those other species to raise their young. The host bird parents typically cater to the largest birds in the nest, which in this case is the cowbird young.
Inattention by the parents leaves the young warblers to wither and often die.
Efforts to trap, poison or otherwise remove the cowbirds from areas where the warbler nests have helped ensure that warbler babies can thrive.
Bringing the Kirtland’s warbler back from the brink of extinction and making sure it has appropriate nesting space has been a conservation success story that will continue into the future, said William Rapai, executive director of the Kirtland’s Warbler Alliance.
Created in 2014, the alliance is one of many public and private groups working together to ensure the warbler thrives.
“People come from all over the world to see it every spring because of its unusual story,” Rapai said. “This is a bird of fire. Unfortunately, we can’t allow fire to run wild across the landscape anymore, so we have to harvest trees and plant young trees to accommodate it.”
He pointed out that other species such as turkey, grouse, whitetail deer and snowshoe hare also benefit from the young forests and open spaces that warblers need.
And because it creates clear spaces on the landscape, the cutting of older trees also reduces the risk of later fire. Jack pine trees have a relatively short life as trees go, and they become a greater fire risk when they are older and larger.
“If we do not harvest those trees, it increases the chance of a disastrous fire that could run across the landscape and do tremendous damage, not just to forests but to people and their houses and property,” Rapai said.
Want to see a Kirtland’s warbler?
The Michigan Audubon Society and Hartwick Pines State Park work together to offer birdwatching tours to find the Kirtland’s warbler in the wild from May 27-June 30.
Tours are at 7 a.m. weekdays and 7 a.m. and 11 a.m. Saturdays and Sundays and leave from Michigan Forest Visitor Center at Hartwick Pines, located along M-93, just east of I-75, near Grayling.
Tours cost $15 per person, and a state Recreation Passport is needed to enter the park.
Dress appropriately for the weather and be prepared to walk up to a mile or so with good shoes or boots. Sunscreen, bug repellent and a hat will help keep you comfortable on the tour. Binoculars, a spotting scope or a camera with a telephoto lens are helpful in getting a good look at the warblers.
Register online for tours: https://www.michiganaudubon.org/calendar/.
Across Michigan, the story of the comeback of Kirtland’s warblers is a worthy success lauded by many. Efforts to showcase the warbler and even celebrate its occurrence in our state bear witness to our affinity with this species.
The Kirtland’s warbler even appears on a specialized Michigan license plate.
In short, the bird is the word.