by william rapai
It’s July, and in northern Michigan’s jack pine forests the Kirtland’s warblers are busy tending to their young birds that have hatched this spring.
Over the next few months, the warblers will feed their young until they are old enough to survive on their own and start to prepare for their fall journey back to The Bahamas by replacing their feathers and putting on as much fat as possible. This cycle, which has occurred for thousands of years, has been made possible through careful management of the forests by us humans. But it wasn’t always like that.
For centuries, the warbler benefitted from fires started by Native Americans to improve their hunting grounds or naturally occurring wildfires started by lightning to renew the landscape and supply them with another batch of fresh young trees.
But as more people moved in and settlement grew in the early 20th century, fire became the enemy; it was extinguished as soon as it was discovered. That shift allowed forests to mature well beyond the nesting demand of Kirtland’s warblers and their numbers dwindled to the point that it was among the first species to be placed on the federal Endangered Species List in 1967.
That could have been the end for the warbler, but a small group of biologists began an effort to prevent the Kirtland’s warbler from going extinct. Working together, they formed the Kirtland’s Warbler Recovery Team to help make sure the bird did not go extinct. To that end, they turned immediately to the jack pine habitat for solutions. If fire was too dangerous, they reasoned, they could do the second-best thing: create a landscape that looked like it had been burned by a wildfire.
Wildfires do not burn across the landscape uniformly. Some parts of a fire will burn cooler, other parts will burn hotter, while in other parts of the fire there may be little or no evidence of the fire’s passage.
Using this knowledge, biologists and foresters developed a technique of planting trees in a pattern that would mimic the randomness of wildfire. Jack pine seedlings would be planted in rows that, when viewed from overhead, look like waves on the ocean. On the ground, the pattern created alternating areas of dense pines and openings. The openings would provide space for blueberries, ferns and grasses to grow prolifically. In other areas of the plantation, mature live trees and old dead trees would be left standing to give male Kirtland’s places with high perches to sing from.
The opposing wave pattern was instituted in the mid-1960s and the results were immediate. As soon as the habitat was old enough to meet the warblers’ needs, they moved right in. The result was the rapid growth of the Kirtland’s warbler population to the point where it was removed from the Endangered Species List in 2019.
It might sound like the story has ended successfully, but that would not be the case. The Kirtland’s warbler is considered a “conservation reliant” species, which means all the conservation work that was done to keep it from going extinct in the past must continue for as far as we can see into the future.
The opposing wave pattern that was so valuable to Kirtland’s warbler conservation has been refined over the succeeding decades. The biologists and foresters at the Michigan Department of Natural Resources and the U.S. Forest Service use an “adaptive management” technique to help guide their decisions.
It’s a framework common in both business and conservation that provides users with feedback on their actions and gives them opportunities to learn, adapt and improve their work in an unending circle. With that in mind, both the DNR and the Forest Service are committing a percentage of their land dedicated to Kirtland’s warbler management to experiments that may further improve the opposing wave or eliminate it in favor of something that proves to be better.
And along the way, those biologists and foresters have learned that while the trees have been planted in a way that will benefit the Kirtland’s warblers, the harvesting of mature forests and planting of young forests have benefits that go way beyond keeping the warbler’s population healthy. That is a result of the conservation effort that has had one eye on the health of the Kirtland’s warbler population and one eye on other species that occupy this ecosystem, such as white-tailed deer, wild turkey, black bear and the upland sandpiper.
Still, the biologists and foresters who lead the Kirtland’s Warbler Conservation Team are asking themselves if there are ways to manage the jack pine more efficiently that would provide even wider benefits.
The jack pine ecosystem is home to many rare and specialized wildlife and plant species like pale agoseris, secretive locust, spruce grouse and of course, the Kirtland’s warbler. Ecological pressures – development, land parcelization, less frequent and more intense wildfires and climate change – all threaten natural biodiversity.
Management efforts that emphasize biodiversity aim to meet the needs of all native species that share this landscape because ecosystems with greater species diversity are more productive and resilient to change.
Beyond the ecological benefits, people appreciate the rich variety of wildlife, wildflowers and pollinators that make biodiverse ecosystems so spectacular.
The Northern Pine Plains Partnership, which consists of natural resource professionals, including those leading Kirtland’s warbler conservation, is also working to restore and protect biodiversity throughout the jack pine ecosystem for the benefit of all species.
Steve Roels, the coordinator of the Kirtland’s Warbler Conservation Team for American Bird Conservancy, agrees that wise management has built something special in the jack pine.
“It’s a magical experience early in the morning when the nocturnal calls of Eastern whip-poor-wills and American woodcocks yield to the dawn chorus of Kirtland’s warblers and Vesper sparrows,” Roels said. “It’s no wonder the region draws thousands of birders, even from abroad, whose love for birds supports many small businesses throughout the region.”
Hopefully, we will remain committed to the jack pine management that will keep these forests special for thousands of years to come.