Hiawatha National Forest

Michigan’s Hiawatha National Forest is home to diverse wildlife, including gray wolves, deer, monarch butterflies, bald eagles, and one of North America’s rarest songbirds, Kirtland’s warbler.

Tree planting efforts on Hiawatha contribute to the recovery of this rare bird, a habitat specialist that requires young jack pine stands for breeding and nesting. Since 2011, over two million jack pine seedlings have been planted across nearly two thousand acres, with another 100,000 being planted in 2024.

After arriving from its winter grounds in the Bahamas in the spring, the warblers breed and nest in young jack pine forests of Hiawatha National Forest. They nest on sandy soil underneath young jack pines that are between 6 and 22 years old, 5 to 20 feet tall, and have enough space between them for adequate sunlight, yet dense with abundant foliage. Why such specificity? When the trees are about six years old, the lower branches are just long enough to reach near the ground and hide a nest underneath, while the sunlight keeps the foliage alive and fluffy. As the trees age, taller branches block sunlight to the lower branches, which then begin to die and can no longer conceal a nest.

The loss of suitable habitat prompted the Kirtland’s warbler to be one of the first species to be protected under the Endangered Species Act of 1973. Historically, fire played an important role in jack pine ecosystems. Fires cleared out thick brush and old trees and allowed the jack pine’s serotinous cones to release seeds and regenerate new stands of young jack pine, essential for Kirtland’s warblers. Decades of fire suppression has yielded dense older stands, inhibiting the establishment of young stands and restricting the warbler’s habitat. Habitat management and tree planting helps to imitate the effects of fire and create suitable habitat for the warbler.

While Kirtland’s warblers remain rare, these habitat specialists are on the rise and they were removed in 2019 from the federal list of endangered species. Their numbers have increased from about 200 pairs in the early 1970s to about 2,245 pairs in 2021 at their nesting grounds in northern Michigan, Wisconsin, and Canada.