Welcome to the simultaneous finish line and starting line, Global ReLeaf enthusiasts! Indeed, this week’s journey — the final of a 25-year endeavor — takes us all the way back to our very first Global ReLeaf project. Before Global ReLeaf blossomed into the successful restoration effort it is today (50 million trees and counting!), our restoration work started with 23,000 tiny, humble trees to protect one small bird: the Kirtland’s Warbler.
The 1990s quiet planting in AuSable State Forest provided thousands of jack pine seedlings to ensure survival of the then-endangered bird. While small, Kirtland’s warblers are very particular when it comes to space and their habitat of choice. Indeed, the birds have very rigid habitat requirements for nesting: a breeding pair typically requires a whopping 6 to10 acres of nesting territory and prefer to nest in areas with more than 80 acres of jack pine coverage. In addition, this land is limited typically within the confines of the lower peninsula of Michigan. They are a bit ageist with their tree preferences, as well — the birds will only begin to nest in the jack pine stands when the trees reach 5 feet tall — about 5 to 8 years of age — and will only inhabit the trees until the jack pine reaches about 16 to20 years of age, when the lower limbs that the warblers like to call home begin dying off.
However, fire suppression, invasives and habitat loss wreaked havoc on this little bird. By 1951, the Kirtland’s warbler population was low enough that only 500 singing males were accounted for. These near-extinction numbers granted the bird a federal endangered listing in 1967, and left many perplexed on how to protect the warbler.
In fact, beyond habitat loss and fire suppression (as jack pines require fire to fully release their seeds), another force threatened the fragile warbler: the brown-headed cowbird. The cowbirds survived by following bison herds, evolving a strategy of nest parasitism in order to thrive along their wandering route. And, their target when the warbler was most vulnerable? Kirtland’s warbler chicks. Cowbirds would lay their eggs in warbler nests, often removing the host’s eggs and causing the baby cowbirds’ new warbler foster parents to unknowingly use valuable resources and careful care to raise the bigger, more competitive cowbird chicks.
Luckily, the Kirtland’s warbler has become one of our favorite success stories, so this story does have a happy ending!
American Forests recognized the immense threats to the warblers and began teaming up with the Michigan Department of Natural Resources and the U.S. Forest Service to plant our first young jack pine stand for future warbler habitat. This effort has now culminated into American Forests and our partners planting more than 1.7 million jack pine trees across 2,000 acres in a short 25 years. In addition, cowbird control measures have ensured the Kirtland’s warbler can continue to thrive in their new habitat. And, the numbers show that these efforts have worked: by 2011, the number of singing Kirtland’s warbler males had risen to 1,828 individuals, effectively helping the bird to avoid its near-extinction status.
The resurgence of the Kirtland’s warbler paints a picture of success after years of collaboration, careful problem-solving and action to restore a threatened bird — and ecosystem. The story of the Kirtland’s warbler is one that we often use as motivation at American Forests, as it showcases the incredible power that forests can have in reversing dangerous trends. There are more challenges to face in the coming 25 years: human population growth, habitat loss and climate change, to name a few. Global ReLeaf has tackled these challenges in the past, and American Forests will no doubt continue to address these issues in the next 25 years, as now — more than ever — forests will be crucial for all of us to protect and restore.