Cerulean Warbler Photo by Lloyd Spitalnik. Copyright 2007.

The Cerulean Warbler is a woodland warbler that breeds in mature, deciduous, upland and bottomland forests in association with both emergent canopy trees and small canopy gaps.

This Neotropical migratory bird breeds in eastern North America and primarily in the Ohio Hills and Cumberland Plateau physiographic areas. However, sizable populations may exist in the Central Hardwoods Bird Conservation Region (CHBCR), especially the Missouri and Arkansas Ozarks.

The U.S. Fish and Wildlife Service considers the Cerulean Warbler a species of management concern and a resource conservation priority. A petition was filed in 2000 to list the Cerulean Warbler as a federally threatened species, but the USFWS determined that the listing was not warranted at the time. The Cerulean Warbler more recently was identified by the USFWS as a “focal species” for conservation efforts by the Joint Ventures and other public-private partnerships. However, before efficient conservation efforts can get underway, better information is needed on where the birds occur in manageable numbers.

This project was designed to develop methods for and carry out a systematic, quantitative assessment of the distribution and abundance of Cerulean Warblers in the CHBCR.

Surveys occurred on public lands to avoid the difficulty of contacting multiple private land owners for permission to collect data on their land.

To locate potential sampling sites, a GIS was used to overlay maps of public lands with maps of potential Cerulean Warbler habitat, defined as large blocks of forest in landscapes that are most likely to support the mesic forests that Cerulean Warblers are associated with. Final sampling sites (shown in red) were then randomly chosen from areas of potential Cerulean Warbler habitat on public land (shown in green).

Research scientists associated with the US Forest Service and the University of Missouri developed a sampling design and point count survey methodology appropriate for estimating densities of Cerulean Warblers.

Observers from five cooperating states (Arkansas, Illinois, Kentucky, Missouri, Tennessee) conducted counts at 1,261 points from late May to the end of June 2007.

Of these 1,261 points, 1,164 were road-based and 97 were river-based. River-based counts occurred in Missouri and Kentucky. Counts were divided by state as follows: 535 in Missouri, 439 in Arkansas, 196 in Kentucky, 50 in Tennessee and 41 in Illinois.

Cooperators detected 105 Cerulean Warblers (43 by rivers, 62 by roads). Of the 105 detections, most occurred in Missouri (74) followed by Arkansas (18), Kentucky (9) and Tennessee (4). Cooperators in Illinois did not detect Cerulean Warblers on their counts.

Point-count surveys will be conducted again in 2008, with a quantitative analysis of the data to follow.