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An orange, black and cream colored butterfly perched on a yellow flowering plant
Information icon Puerto Rican harlequin butterfly. Photo by Jan Zegarra, USFWS.

Service seeks public comment on proposal to list rare Puerto Rican butterfly as threatened under Endangered Species Act

Critical habitat also proposed, along with 4(d) rule that tailors protections to those needed while supporting other activities that don’t hinder recovery

Today the U.S. Fish and Wildlife Service is proposing to list the Harlequin butterfly as threatened under the Endangered Species Act (ESA). The Service is also proposing to designate critical habitat for the butterfly, as well as a special 4(d) rule. The Service will accept public comments on this proposed decision until 12/14/2020 (60 days after publication in FR).

Six populations of the Puerto Rican harlequin butterfly, a medium-sized butterfly native to Puerto Rico, are known to exist in the world. Each of those populations represent less than 100 total individuals in any given year.

“The Puerto Rican harlequin butterfly is found nowhere else in the world besides Puerto Rico,” said the Service’s Regional Director, Leopoldo Miranda. “Given the challenges that the species is facing and the Service’s partnership-based approach to conservation, much work has already been set in motion by diverse local, state and federal partners to stabilize populations of the butterfly and lay the foundation for its recovery.”

Primary threats to the butterfly include habitat modification, fragmentation and losses caused by urban development and agricultural practices. Relative to historical conditions, their distribution is fragmented among remnants of native forest located in northwestern and southwestern Puerto Rico.

The proposed critical habitat for the butterfly only includes occupied habitat where the species already occurs, including a two-kilometer buffer around breeding sites. In total, approximately 41,266 acres are being proposed – 56% private lands, 39% owned and managed by the Puerto Rico Department of Natural and Environmental Resources, and 5% percent owned by other agencies. The proposed special 4(d) rule for the harlequin butterfly tailors protections to those needed to protect and recover it and address primary threats, while allowing certain activities that do not significantly harm it, or are beneficial.

The proposed 4(d) rule for the Puerto Rican harlequin butterfly will include an exception for federal and Commonwealth agency conservation activities, including collection of broodstock, tissue collection for genetic analysis, captive propagation, and stocking into currently and historically occupied areas. The following exceptions are also being considered: (1) reforestation projects that promote the establishment or improvement of habitat conditions for the species by the planting of native trees and the host plant Oplonia spinosa, selective removal of exotic trees, seasonal pruning of native and exotic vegetation, or a combination of these; (2) non-native species removal (e.g., invasive grass) and agricultural pest monitoring; and (3) fire prevention programs.

Since 2011, the Service has been working with Puerto Rico (through the Puerto Rico Department of Natural and Environmental Resources) and other partners such as the Fort Worth Zoo, North Carolina Zoo, Para La Naturaleza, and Liga Ecológica Quebradillana to locate populations of the Puerto Rican harlequin butterfly, describe its habitat, and identify threats. In addition, the Service has been providing technical assistance on projects that may benefit the Puerto Rican harlequin butterfly, working to increase awareness of this rare species.

Comments on the proposed rule must be received by 11:59 p.m. Eastern Time on 12/14/2020 (60 days after publication in FR). We must receive requests for public hearings, in writing, at the address shown in the more information section below by 11/27/2020 (45 days after publication in FR).

You may submit comments by one of the following methods:

  1. Electronically: Go to the Federal eRulemaking Portal. In the Search box, enter FWS–R4–ES–2020–0083, which is the docket number for this rulemaking. Then, click on the Search button. On the resulting page, in the Search panel on the left side of the screen, under the Document Type heading, check the Proposed Rule box to locate this document. You may submit a comment by clicking on “Comment Now!”
  2. By hard copy: Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS–R4–ES–2020–0083, U.S. Fish and Wildlife Service, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041–3803.

We request that you send comments only by the methods described above. We will post all comments on This generally means that we will post any personal information you provide us (see Public Comments, below, for more information).

Availability of supporting materials: For the critical habitat designation, the coordinates or plot points or both from which the maps are generated are included in the administrative record and are available at and at under Docket No. FWS–R4–ES–2020–0083, and at the Caribbean Ecological Services Field Office (see more information section below). Any additional tools or supporting information that we may develop for the critical habitat designation will also be available at the Service website and Field Office set out above, and may also be included in the preamble and/or at

More information

Edwin Muñiz, Field Supervisor, U.S. Fish and Wildlife Service, Caribbean Ecological Services Field Office, P.O. Box 491, Road 301 Km 5.1, Boquerón, Puerto Rico 00622; telephone 787–851–7297. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Relay Service at 800–877–8339. 


The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information on our work and the people who can make it happen, visit Connect with the Service on Facebook, follow our tweets, watch the YouTube Channel and download photos from Flickr.

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