Cerulean Warbler Habitat Management

USGS Cooperative Research Unit Corner

Cerulean Warbler Habitat Management

The Appalachian Region is known for its extensive tracts of mature hardwood forest and high biodiversity, including that of songbirds. The region is a stronghold for the cerulean warbler, containing about 75 percent of the population. The USGS West Virginia Cooperative Fish and Wildlife Research Unit, in collaboration with the Cerulean Warbler Technical Group, National Council for Air and Stream Improvement, National Fish and Wildlife Foundation, Appalachian Mountains Joint Venture (AMJV), and researchers and managers from universities, state agencies, U.S. Fish and Wildlife Service (USFWS), U.S. Forest Service (USFS), and private landowners in West Virginia, Ohio, Kentucky, and Tennessee, recently completed a six-year study with the objective of identifying forest management techniques that can enhance cerulean warbler habitat.

The cerulean warbler is a species of high conservation concern due in part to an estimated 70 percent population decline over the last 40 years. Several factors contribute to its decline, including loss and degradation of forested habitat in its summer breeding range as well as its winter range in Central and South America. Not only is the amount of forest in the landscape important for these birds, but also the quality of the forest in terms of vegetative structure and composition. Cerulean warblers breed in mature deciduous forests throughout the eastern United States, but are particularly abundant in oak-dominated forests that contain canopy gaps and a complex canopy structure.

Anecdotal evidence that creating some canopy breaks in a closed canopy forest improves the habitat quality for cerulean warblers suggested that harvesting timber might be a useful tool for managing forests to benefit this species. The recent study, led by the West Virginia Unit, used a controlled, experimental approach to quantify cerulean warbler abundance, density, nesting success, return rates and habitat relations. Additionally, the response of the overall bird community to forest management was quantified so that associated species could be considered in habitat management decisions. The research helped to identify ways that wildlife and forest managers can use silviculture to improve breeding habitat for the cerulean warbler and other avian species. Partners also developed Habitat Management Guidelines that several state agencies are now implementing on state lands in the Appalachian Region.

The West Virginia and Virginia Units then initiated a follow-up study to evaluate the implementation phase of forest habitat management for cerulean warblers. Working with the AMJV and state wildlife management agencies in West Virginia, Virginia, Kentucky and Pennsylvania, researchers are studying cerulean warbler and associated species' responses within the context of applied forest management under a broader range of conditions than the original study. The follow-up study is also evaluating the response of cerulean warblers and associated species to a mosaic of timber harvests which are often used to provide a variety of wildlife habitat conditions within close proximity. The results from this study will be used to further refine the cerulean warbler habitat management guidelines.

Implementation of forest habitat management for cerulean warblers is poised to expand throughout the central Appalachian Region. The AMJV Partnership recently received an $8 million Regional Conservation Partnership Program (RCPP) award from the Natural Resources Conservation Service (NRCS) for their Cerulean Warbler Appalachian Forestland Enhancement Project to enhance cerulean warbler and associated species habitat on private lands in the Appalachian region by implementing the Habitat Management Guidelines. Much of the existing cerulean warbler population occurs on private lands, so conservation of this species is dependent on working with private landowners in the region.

Additional efforts for cerulean warbler habitat management are underway with the Office of Surface Mines (OSM) Appalachian Regional Reforestation Initiative (ARRI) on mined lands. The West Virginia Unit developed a brochure for ARRI emphasizing why mineland reforestation is important for Appalachian wildlife which led to a Reclamation Advisory that provides guidance on reforestation practices to provide high quality habitat for native forest wildlife on reclaimed surface mines. Because a focal species in this advisory is the cerulean warbler, the advisory emphasizes approaches for reducing forest loss and fragmentation. The American Chestnut Foundation and Green Forests Work, in conjunction with ARRI and OSM, also will receive funds from the RCPP award mentioned above to reforest legacy surface mines under private ownership using the ARRI Reclamation Advisories to guide their reforestation efforts.

All of these efforts are working towards improving the quality and quantity of forest habitat for cerulean warblers and the many other species that depend upon forested landscapes in the Appalachian region.

The ONB features articles from Cooperative Fish and Wildlife Research Units across the country. Working with key cooperators, including WMI, Units are leading exciting, new fish and wildlife research projects that we believe our readers will appreciate reading about. This article was written by Petra Wood, pbwood@wvu.edu, with the USGS West Virginia Cooperative Fish and Wildlife Research Unit at West Virginia University Division of Forestry & Natural Resources.

July 14, 2015