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A white breasted bird with blueish grey feathers.
Information icon Elfin-woods warbler. Photo by Mike Morel, USFWS.

Final critical habitat designation for the Elfin-eoods warbler

Why did the U.S. Fish and Wildlife Service (Service) list the elfin-woods warbler in 2016 as threatened under the Endangered Species Act (ESA)?

The Service analyzed the best available science and determined the elfin-woods warbler is threatened throughout all of its range by the following factors:

  1. Habitat modification on private lands under agricultural and other land use that involve vegetation clearance.
  2. Other natural or manmade factors, such as restricted distribution, lack of connectivity, genetic drift, hurricanes, human-induced fire, and climate change.

Where does this bird live?

The elfin-woods warbler is found in Puerto Rico and currently found only in El Yunque National Forest in eastern Puerto Rico and the Maricao Commonwealth Forest and adjacent private lands in western Puerto Rico. Its habitat is humid montane forests with high rainfall, high humidity, low sun exposure, low temperatures, and constant winds. It is found on the summits of the mountains and its habitat is composed of dense stands of short, small diameter and twisted trees and shrubs.

What has been done to help conserve this bird?

In 2014, the Service, the Puerto Rico Department of Natural and Environmental Resources and the U.S. Forest Service signed a Candidate Conservation Agreement (CCA) to work together to conserve the elfin-woods warbler and restore suitable habitat in the El Yunque National Forest and Maricao Commonwealth Forest. With this CCA, the parties agreed to promote, develop, and implement best management practices to avoid any potential threat to suitable and occupied warbler habitat and populations.

What kinds of substantive comments did the Service receive on the proposal to designate critical habitat for the elfin-woods warbler?

The Service reviewed all comments received from the peer reviewers for substantive issues and new information regarding the critical habitat designation for the elfin-woods warbler. The peer reviewers generally concurred with our methods and conclusions and provided additional information, clarifications, and suggestions to improve the final rule.

Two reviewers recommended additional areas for critical habitat designation:

  1. Expand the westernmost side of Unit 1 within the Maricao Commonwealth forest
  2. Expand the westernmost side of Unit 1 outside the Maricao Commonwealth forest
  3. Proposed Guilarte Commonwealth Forest as another area outside the geographic range to be designated as critical habitat.

Considering the peer reviewer’s comments, we reanalyzed the Maricao area and concurred with expanding Unit 1. We added 363 acres (2.8 percent) to the originally proposed critical habitat within the Maricao Commonealth Forest, for a total of 27,488 acres for the elfin woods warbler.

The Service concluded that the westernmost areas outside the Maricao Commonwealth Forest did not fit the criteria for critical habitat. In addition, we did not find Guilarte Commonwealth Forest essential for the conservation of the species based on the best available information at the time of designation. Nonetheless, it is important to indicate that a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be needed for the recovery of the species. We recognize that critical habitat designated at a particular point in time may not include all of the habitat that may later determine is necessary for the recovery of the species. Thus, areas that are important to the conservation of the species, both inside and outside the critical habitat designation, will continue to be subject to: (1) Conservation actions implemented under section 7(a)(1) of the ESA, (2) regulatory protections afforded by the requirement in section 7(a)(2) of the ESA for Federal agencies to insure their actions are not likely to jeopardize the continued existence of any endangered or threatened species, and (3) the prohibitions of section 9 of the ESA. These protections and conservation tools will continue to contribute to recovery of this species.

What is critical habitat?

Critical habitat is a term in the ESA that identifies geographic areas containing features essential to the conservation of a listed species and which may require special management considerations or protection. Specifying the location of habitat essential to the conservation of the species helps federal agencies identify areas to utilize their authorities to benefit listed species. The designation also allows efforts of other conservation partners, such as state and local governments, non-governmental organizations and individuals to be focused on areas that will provide the greatest benefit to the species.

Designation of critical habitat also provides non-regulatory benefits by informing the public of areas that are important to the species’ recovery and identifying where conservation actions would be most effective. Learn more about critical habitat.

What is the purpose of critical habitat?

Critical habitat is a tool to identify areas that are important to the conservation and recovery of a listed species. It is also used to notify federal agencies of areas that must be given special consideration when they are planning, implementing, or funding activities. Federal agencies are required to consult with the Service to ensure actions they carry out, authorize, fund, or permit are not likely to result in the destruction or adverse modification of critical habitat. A critical habitat designation has no effect when a federal agency is not involved. For example, a landowner undertaking a project on private land that involves no federal funding or permitting has no additional responsibilities if his or her property falls within critical habitat boundaries.

Under the ESA, when the Service determines that any species is threatened or endangered, it must designate critical habitat “to the maximum extent prudent and determinable.”

What areas are designated as critical habitat designation for the elfin-woods warbler?

The Service designated three units in Puerto Rico as critical habitat for the elfin-woods warbler. In total, the Service is recommending the designation of approximately 27,488 acres as critical habitat for the species. Of that, 89 percent is currently occupied habitat and 11 percent is currently unoccupied.

The areas are within El Yunque National Forest, Carite Commonwealth Forest, and Maricao Commonwealth Forest and adjacent areas. Municipalities included in these units are: Caguas, Canóvanas, Cayey, Ceiba, Guayama, Las Piedras, Maricao, Naguabo, Patillas, Rio Grande, San Germán, San Lorenzo, Sabana Grande, and Yauco. Land ownership within the proposed critical habitat area consists of federal (42 percent), Commonwealth (43 percent), and private (15 percent).

How were these areas chosen for critical habitat?

Biologists considered physical or biological features needed for life processes and successful reproduction of the species. These include: space for individual and population growth and for normal behavior; cover or shelter; food, water, air, light, or other nutritional or physiological requirements; and sites for breeding and rearing offspring. Forests with elfin-woods warblers have high rainfall, high humidity, low insolation, low temperatures, and constant winds. Warblers are found on the summits of the mountains with dense stands of short, small diameter, twisted trees and shrubs.

What changes did the Service make from the proposed critical habitat rule to the final critical habitat designation?

  1. Unit 1 Maricao was expanded to include additional area as critical habitat. Unit 1 now covers a total of approximately 12,978 ha (5,252 ac). The increase is about 2.8 percent of the proposed area for Unit 1. The acreage calculation for this Unit was updated accordingly.
  2. The Service corrected an error in the acreage of critical habitat Unit 3 Carite. The error resulted from rounding of numbers. Changes made resulted in no more than 1ac (0 to 1 ha) increase for this Unit.
  3. The Service refined our description of the physical and biological features to more accurately reflect the habitat needs of the species. No adjustments to the unit boundaries were needed as a result of this change.
  4. We updated the coordinates or plot points from which the maps were generated. The information is available at regulations.gov at Docket No. FWS–R4–ES–2020–0030, and at the Caribbean Ecological Services Field Office.

Why did the Service designate one critical habitat area that is currently unoccupied by the warbler?

The unoccupied unit is in the Carite Commonwealth Forest, which is part of the warbler’s historical distribution. Although it has been more than 15 years since the species was seen there, the area still has suitable habitat to allow the elfin-woods warbler to survive and could be a likely site for potential future reintroductions to help the species recover.

What does the economic analysis mean to private landowners in the area?

It is unlikely private landowners will incur costs associated with this critical habitat designation.

Only activities authorized, funded, or carried out by a federal agency require consultation with the Service, and only those projects that are likely to destroy or adversely modify critical habitat may need further consultation or modification. Most of the cost measures factored into the economic analysis relate to the increase in administrative costs to federal agencies, and only apply when consultations are anticipated for projects that may appreciably diminish the conservation value of habitat conditions essential for the species conservation.

What can people do to help the warbler?

  • Promote local shade-grown coffee and encourage the creation or restoration of shade grown coffee plantations.
  • Learn more about the many birds in Puerto Rico. There are about 350 species you may see here. Of those, over a hundred species make their nests and grow their young here in the many habitats Puerto Rico offers.
  • If you are a landowner with land near the Maricao Commonwealth Forest or the El Yunque National Forest and would like to follow-up on any of these options, please contact the Service’s Caribbean Ecological Field Office at Post Office Box 491, Boquerón, Puerto Rico, 00622, or contact Deputy Field Supervisor Marelisa Rivera at (787) 851-7297, or marelisa_rivera@fws.gov to learn what you can do to provide warbler habitat. -Support establishing additional agreements and partnerships with landowners near the Maricao Commonwealth Forest to protect elfin-woods warbler habitat.
  • Protect and support existing shade-grown coffee plantations, and encourage restoration of sun-grown coffee into shade-grown coffee plantations in areas where the warbler has been recorded near the Maricao Commonwealth Forest.
  • Support and initiate habitat restoration projects to provide effective forested corridors for the elfin-woods warbler dispersal throughout the central mountains of Puerto Rico.
  • Support additional landscape surveys to identify additional areas where the bird occurs in Puerto Rico.
  • Support efforts to learn the possible causes of the warbler’s declining status at El Yunque National Forest.

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