Preliminary evaluation of habitat use, pairing rate, and reproductive success in an experimental breeding habitat planted for Kirtland’s Warblers ( Setophaga kirtlandii )

Abstract

Sustaining management indefinitely for conservation-reliant species presents significant challenges for the conservation community. To reduce the costs of conservation reliance, managers can use adaptive management to evaluate how cost-saving changes to traditional management affect wildlife populations. In 2015, Michigan Department of Natural Resources managers began creating experimental breeding habitat that involved mixing a higher-value tree, red pine ( Pinus resinosa ), into traditional jack pine ( Pinus banksiana ) plantations to increase the economic and ecological value of stands managed for Kirtland’s Warblers ( Setophaga kirtlandii ). We report on the habitat use, pairing success, and reproductive success of Kirtland’s Warblers occupying an experimental mixed pine plantation in 2021. Compared to an identically-aged, adjacent jack pine plantation, we found that the mixed pine stand had slightly lower male density, a significantly lower pairing rate, and similar reproductive success. We also found that within the mixed pine stand, individuals rarely used red pine trees for foraging and never built nests under them. Because of the small sample size, our results are preliminary, and they provide mixed evidence about the suitability of these mixed pine stands for Kirtland’s Warblers. We demonstrate that Kirtland’s Warblers will use and breed in the new habitat type. However, if the lower pairing rate we found in the mixed pine stand is confirmed by future monitoring of additional stands, there is potential for concern. Our results are too preliminary to use for making decisions about the success of the mixed pine habitat experiment, but we urge managers to implement monitoring programs for all experimental plantations that include estimation of not only male density, but also pairing rate and reproductive success.

Keywords

• adaptive management
• conservation
• conservation reliance
• endangered
• forestry
• habitat use
• kirtland’s warbler
• pairing rate
• red pine