The golden-cheeked warbler (Setophaga chrysoparia) and the black-capped vireo (Vireo atricapilla) are two species of small, insectivorous birds facing the threat of population decline due to habitat destruction.
Noted for being the only bird species to nest exclusively in Texas, the golden-cheeked warbler resides in the Ashe juniper-oak woodlands of central Texas and is typically found nesting in the area’s steep-sided canyons, ravines and adjacent uplands. Golden-cheeked warblers arrive in Texas in mid-March to nest and raise their young, then begin migrating south in July to spend the winter in Mexico and Central America.
While golden-cheeked warblers breed solely in Texas’s woodland habitat, the black-capped vireo prefers nesting in patchy shrubs, like shin oak and sumac, that can be found in parts of Texas, Oklahoma and Mexico. Beginning in late March, black-capped vireos arrive at their breeding habitat to nest until August, then start migrating to Mexico for the winter.
Evaluating Project Sites Through Surveys
Many researchers have indicated that the population decline of both the golden-cheeked warbler and black-capped vireo is the result of destruction and fragmentation of the species’ breeding habitats. The juniper-oak woodlands that golden-cheeked warblers rely on, along with the black-capped vireo’s shrubland habitat, are being cleared for various agricultural and construction projects.
With the growing threats to habitat, and with population declines, many projects throughout central Texas are required to conduct presence/absence surveys for golden-cheeked warblers and black-capped vireos as a way of determining if the species are present at a specific project site. These surveys can often significantly impact project schedules because surveying is permitted only during certain times of the year to minimize potential impacts to the birds.
Current U.S. Fish and Wildlife Service (USFWS) survey protocol establishes March 15-June 1 as the designated season for golden-cheeked warbler surveying — with the requirement that no less than 60 percent of surveys can be conducted before May 15. For the black-capped vireo, the surveying season runs from April 10 through July 1, with at least 50 percent of surveys required to be conducted before May 15.
Along with these scheduling requirements, potential project sites must be surveyed five times by a USFWS Section 10(a) federally permitted individual — with no two surveys occurring within a five-day period. During these presence/absence surveys, if a project site is confirmed as being occupied by either the golden-cheeked warbler or black-capped vireo, the species and its habitat is protected under the Endangered Species Act (ESA).
During the breeding season — March 1-Aug. 31 — the USFWS recommends establishing a 300-foot buffer between the occupied golden-cheeked warbler/black-capped vireo habitat and construction activities like driving construction equipment, drilling, clearing, etc., and refraining from these activities unless they are initiated prior to March 1 and if the construction disturbance is continuous.
Endangered Status
Although the golden-cheeked warbler and black-capped vireo were listed as endangered in May 1990 under an emergency rule (55 FR 18844), there was recently a petition to the USFWS to delist the golden-cheeked warbler, citing 25 years of additional studies showing that the amount of warbler habitat and population is much greater than originally thought. On June 2, 2016 the USFWS found that the petition to delist the golden-cheeked warbler from the ESA did not present substantial information warranting the delisting.
The black-capped vireo was also listed as endangered in October 1987 without critical habitat (52 FR 37420-37423). The USFWS completed a status review of the species on June 19, 2007, and recommended that the black-capped vireo be downlisted from ‘endangered’ to ‘threatened’ status. Additionally, on Sept. 9, 2013 the USFWS recommended in a 90-day finding to reclassify the black-capped vireo from ‘endangered’ to ‘threatened’.
For now, the golden-cheeked warbler’s status remains clear, but the black-capped vireo’s future on the endangered list is unclear, which is why you need to know how to handle ongoing conservation efforts going forward.
Habitat surveys can help determine if a project within the golden-cheeked warbler/black-capped vireo range could adversely affect the species or potentially ESA protected habitat.
Unsure if your project is affected? We have a team of threatened and endangered species specialists who can assess a project’s potential impact on golden-cheeked warblers and black-capped vireos, and can offer a variety of survey and mitigation options. If you’d like to learn more, comment below.
Photo credit: Golden-cheeked warbler by U.S. Army Environmental Command is licensed under CC BY 2.0.