Maintaining the recovery of the formerly federally endangered Kirtland’s warbler (Setophaga kirtlandii) requires continual creation of early-successional jack pine (Pinus banksiana) habitat every year, which, in turn, requires a steady supply of commercial timber sales. However, dedicated Kirtland’s warbler habitat plantations are established at high stem densities (ca. 3600 trees ha−1) which can delay the production of marketable timber compared to a conventional forestry planting density (ca. 1900 trees ha−1). We used a retrospective approach to assess the impacts of tree density on Kirtland’s warbler occupancy, and an experimental approach to understand benefits and costs of pre-commercial thinning of Kirtland’s warbler habitat plantations. We observed an unexpected negative relationship between realized plantation density and maximum occupancy by Kirtland’s warbler singing males. We found that thinning of high-density jack pine planted for Kirtland’s warbler habitat resulted in increased diameter growth, increased live crown ratio, and a trend towards increased intrinsic water-use efficiency in the older age classes. These findings provide strong support for the importance of using adaptive management approaches to more rigorously evaluate the impacts of plantation spacing on Kirtland’s warbler productivity. Although increases in volume growth and timber prices following thinning are unlikely to ever recoup the costs of implementation, we argue that thinning could still be an important tool to accelerate the rate at which these stands attain marketability for the timber sales that are necessary to create a continuous supply of Kirtland’s warbler breeding habitat. •Kirtland’s warbler occupancy did not increase with increasing stem density.•Kirtland’s warbler occupancy was influenced by stand age and habitat connectivity.•Plantations that had aged out of breeding habitat showed no evidence of stagnation.•Financial returns are unlikely to ever recoup the costs of pre-commercial thinning.