In the past, coffee could be grown only in the shade of large trees. This encouraged the protection of the large deciduous forests. Today sun-tolerant varieties of coffee can be grown. Other threats Cerulean warblers migrate between two continents during their yearly life cycle. They are at a higher risk than species that stay in the same area all year.
Cerulean warblers produce only one brood per year.
This may limit their ability to replace themselves in the population as conditions deteriorate. The effects of contaminants have not been investigated. Younger hardwood stands adjacent to mature stands should be protected from timber harvest. These younger trees will provide future habitat for the warblers. Wetland-protection regulations to preserve lowland hardwood forests should be enforced.