USFWS are releasing (meaning introducing) the Guam kingfisher (Todiramphus cinnamominus), known locally as the sihek, on Palmyra Atoll as an experimental population under the ESA. Currently, sihek exists only in captivity and has been extinct in the wild for more than 30 years. The introduction on Palmyra Atoll is outside sihek's historical range because its primary habitat within its native range on Guam has been indefinitely altered by the accidental introduction of the predatory brown treesnake (Boiga irregularis) in the mid-twentieth century. Tools to manage brown treesnakes at a landscape level are beginning to be deployed, but it will take time before these tools are effective. The introduction of sihek to Palmyra Atoll is not a permanent introduction that would support a self-sustaining population; it is intended to facilitate the gathering of information and analysis to optimize efforts for reestablishment of the species on Guam once brown treesnakes can be sufficiently controlled at a landscape scale. USFWS classify this population as a nonessential experimental population (NEP) under the ESA and provide regulations for the take of sihek within the NEP area. This final rule is effective 4 May 2023. POC is Megan Laut, Pacific Islands Fish and Wildlife Office, USFWS, 300 Ala Moana Blvd., Rm 3–122, Honolulu, HI 96850; tele 808–779–9939. (Federal Register 4 April 2023 [Rule] Pages 19880-19894)