Cape May Warbler
- Cape May Warblers are found in old coniferous (>76 years) and conifer-leading mixedwood (>125 years) forests containing spruce and/or balsam fir, particularly stands with spruce >10 m tall with some trees extending above the canopy.1,2
- Important habitat features across their range include an open, mossy understory and richer, wetter sites containing white spruce, balsam poplar, and high alder cover (Saskatchewan).1,3
- Populations of Cape May Warblers increase sharply in areas infested with spruce budworm.1 During outbreaks, they are also found in early-seral forests.4
Response to Forest Management
- Cape May Warblers are very rarely observed in recently disturbed forest stands5 or mid-seral forests.2
- Evidence of use of riparian buffers is mixed for this species. In New England, Cape May Warblers had much lower densities in riparian buffers than unharvested forest.6 In Saskatchewan, Cape May Warblers and other coniferous-associated species used 10 m buffers plus 30 m partially harvested forest, but their abundance compared with unharvested stands was not tested.7
- Cape May Warblers occur at very low densities so there is little information on their responses to different harvest strategies.
- Large retention patches containing >10 m tall white spruce may provide some benefit, however their utility has not been tested for this species.
- Large, old forest stands are likely the most important tool for conserving this species (see Landscape-level Recommendations).8
- Large, old white spruce or spruce-leading mixedwood forests are considered the most important habitat for this species.8 Stand sizes >100 ha or larger areas consistent with NRV are recommended. Remnant forest blocks >50 ha are seen as a minimum for this species.9
- Cape May Warbler use of old black spruce forest and treed fens is uncertain based on available research but there may be some value of these forests.5,10
- Spruce budworm outbreak areas may represent opportunities for increasing populations within infested stands.9
- Microbial controls (e.g., Bt) or lepidopteran-specific insecticides (e.g., tebufenozide) are recommended over other chemical insecticides for controlling spruce budworm outbreaks, as chemical insecticides may have unknown toxicity to Cape May Warblers and other budworm-eating species.11