Abstract
The 1988 amendment to the Fish and Wildlife Conservation Act mandates the U.S. Fish and Wildlife Service (USFWS) to identify species, subspecies and populations (hereafter taxa) of all migratory nongame birds that without additional conservation action are likely to become candidates for listing under the Endangered Species Act (ESA) of 1973. The Birds of Conservation Concern 2021 (BCC 2021) is the most recent effort to carry out this mandate. The overall goal of this report is to identify those bird taxa (beyond those already designated as federally threatened or endangered) that represent the highest conservation priorities of the USFWS. The BCC 2021 is intended to stimulate coordinated, collaborative and proactive conservation actions among international, federal, state, tribal and private partners.
The geographic scope of this endeavor is the United States of America (USA) in its entirety, including island states, commonwealths and territories in the Pacific Ocean and Caribbean Sea and the marine areas delineated as territorial sea, contiguous zone and exclusive economic zone. The BCC 2021 encompasses four distinct geographic scales: 1) the Continental USA, including Alaska; 2) Pacific Ocean islands, including Hawaii; 3) Puerto Rico, the U.S. Virgin Islands and Navassa; and 4) continental Bird Conservation Regions (BCRs) and Marine Bird Conservation Regions (MBCRs), as defined by Bird Studies Canada and NABCI (2014). New to the BCC 2021 is the explicit inclusion of MBCRs.
Bird taxa considered for the BCC 2021 lists include nongame birds, gamebirds without hunting seasons or where harvest is minimal, and subsistencehunted nongame birds in Alaska. Excluded from consideration for the BCC 2021 are bird species not protected under the Migratory Bird Treaties (Federal Register 2020a), taxa already listed as threatened or endangered under the ESA, or taxa that only occur irregularly or peripherally in the USA. Our conservation assessment was based on several factors, including population abundance and trends, threats on breeding and nonbreeding grounds, and size of breeding and nonbreeding ranges. The factor scores and associated thresholds used for identifying birds of conservation concern in the 2014 State of the Birds Watch List (Rosenberg et al. 2014) and the Avian Conservation Assessment Database (Partners in Flight 2019, Punjabi et al. 2019) served as the foundation on which we developed the BCC 2021 lists. Thus, we sought consistency of the BCC 2021 with priorities identified through these other efforts, noting that appropriate differences do occur due to the unique scope and mandate of the Birds of Conservation Concern. The BCC 2021 also represents the first time we tried to unify the assessment system among waterbirds, shorebirds and landbirds.
The BCC 2021 identifies 269 individual bird taxa of conservation concern. Of these, 135 taxa are of conservation concern at the Continental scale, 88 taxa at the BCR scale, 29 taxa on Puerto Rico and the Virgin Islands, and 35 taxa on Hawaii and the Pacific Islands; 18 taxa identified on the Continental/ BCR lists are shared with either Puerto Rico and the Virgin Islands or Hawaii and the Pacific Islands. The number of taxa on the Hawaii/Pacific Island list appears deceptively low, because a high number of birds there are already listed under the ESA. The number of taxa listed within a BCR, which includes those identified as conservation concern at the Continental or BCR scales, ranges from 12 taxa in the Arctic Plains and Mountains to 49 taxa in Coastal California, with an average of 25.4 taxa per BCR. Among MBCRs, the number of taxa ranged from two taxa in the Chuckchi and Beaufort Seas to 13 taxa in the California Current, with an average of 7.4 taxa per MBCR.
Although the bird taxa included in the BCC 2021 are priorities for conservation action, this list makes no finding with regard to whether they warrant consideration for ESA listing. Our goal is to eliminate the need for additional ESA bird listings by implementing proactive management and conservation actions that sustain populations well above thresholds of endangerment. We recommend that these lists be consulted in accordance with Executive Order 13186, Responsibilities of Federal Agencies to Protect Migratory Birds. Many of the taxa identified herein are targets of ongoing conservation attention by national and international initiatives (e.g., Partners in Flight, U.S. Shorebird Conservation Partnership), Migratory Bird Joint Ventures, state and federal natural resource agencies, non-governmental organizations, and other partnerships.