Biological Opinion and Informal Consultation for the Midway Seabird Protection Project, Midway Atoll National Wildlife Refuge Photo: Daniel Clark January 30, 2019 (01EPIF00-2019-F-0049) United States Department of the Interior FISH AND WILDLIFE SERVICE Pacific Islands Fish and Wildlife Office 300 Ala Moana Boulevard, Room 3-122 Honolulu, Hawaii 96850 In Reply Refer To: January 30, 2019 01EPIF00-2019-F-0049 Memorandum To: Acting Refuge and Monument Supervisor, Pacific Islands Refuges and Monuments Office, Honolulu, Hawaii From: Island Team Manager, Oahu, Kauai, North Western Hawaiian Islands, and American Samoa, Pacific Islands Fish and Wildlife Office Subject: Biological Opinion and Informal Consultation for the Midway Seabird Protection Project, Midway Atoll National Wildlife Refuge This document transmits the U.S. Fish and Wildlife Service’s (Service) biological opinion (Opinion) based on our review of the proposed Midway Seabird Protection Project located in Midway Atoll National Wildlife Refuge. This Opinion addresses the impacts of the proposed project of eradicating house mice (Mus musculus) from Midway and potential effects on the endangered Laysan duck (Anas laysanensis). This Opinion was prepared in accordance with section 7 of the Endangered Species Act of 1973 (ESA), as amended (16 U.S.C. 1531 et seq.). Your request for formal consultation was received on November 9, 2019. A separate informal consultation is found in Appendix A for project impacts that may affect but is not likely to adversely affect the federally threatened green sea turtle (Chelonia mydas) Central North Pacific Distinct Population Segment and the endangered plants popolo (Solanum nelsonii) and loulu (Pritchardia remota). This Opinion is based on information provided in (1) the November 9, 2019 Biological Assessment (BA) for your proposed project; (2) meeting held on November 28, 2018, between the U.S. Fish and Wildlife Service Pacific Islands Refuge and Monument Office (PIRMO) staff and our office to discuss the BA; (3) email and verbal communication between PIRMO staff and our office; (4) peer reviewed articles and reports; and (5) other information available to us. A Midway Seabird Protection Project - 01EPIF00-2019-F-0049 2 complete administrative record of this consultation is on file in our office. Our log number for this consultation is 01EPIF00-2019-F-0049. CONSULTATION HISTORY November 9, 2018 – PIRMO submitted a Biological Assessment (BA) and Formal consultation was initiated. November 28, 2018 – PIRMO and the Service met to discuss questions and additional information (e.g., project duration, egg incubation protocols, explanation for percentage of captive birds, captive care protocols, botulism vaccine, injury and mortality estimates, holding time for ducks post bait application) needed to conduct the consultation A list of additional information needed was emailed to PMNM after the meeting. December 7, 2018 – PIRMO emailed the Service additional information requested by the Service on November 28, 2018. The following information was provided to the Service: project duration, egg incubation protocols, explanation for percentage of captive birds, captive care protocols, botulism vaccine and antitoxin information, revised injury and mortality estimates, holding time for ducks post bait application, and clarification and information on other items. December 18, 2018 – The Service emailed PIRMO requesting further information regarding egg incubation, how the issue of ducklings potentially imprinting on humans will be addressed, and the monitoring involved in administering the botulism vaccine to Laysan ducks. December 20, 2018 – PIRMO emailed the Service additional information requested by the Service on December 18, 2018. The following information was provided: clarification that artificial incubation would be conducted only as a last resort, information regarding incubation of duck eggs, measures to be implemented if needed to prevent ducklings from imprinting on humans, and information regarding the monitoring efforts for ducks receiving the botulism vaccine. DESCRIPTION OF THE PROPOSED ACTION Project Description Midway Atoll National Wildlife Refuge (MANWR) lies in the North Pacific Ocean approximately equidistant between North America and Asia. The refuge is also designated the Battle of Midway National Memorial and is within the Papahanaumokuakea Marine National Monument (PMNM). The fringing coral reef, shallow lagoons, and 3 low-lying islands (Sand, Eastern, and Spit Islands), are the breeding grounds for millions of seabirds, the wintering grounds for thousands of shorebirds, and a refuge for critically endangered species like the Hawaiian monk seal (Neomonachus schauinslandi) and Laysan duck (Anas laysanensis). Over 70% of the total global population of Laysan albatross (Phoebastria immutabilis) breeds at the refuge, with a majority of the Midway population nesting on Sand Island. Midway Seabird Protection Project - 01EPIF00-2019-F-0049 3 The Proposed Action is to eradicate house mice (Mus musculus) from Sand Island by delivering a lethal dose of rodenticide to every rodent in a manner that minimizes harm to island residents and the ecosystem while still maintaining a high probability of success, and to maintain the island in rodent-free status in perpetuity. The toxicant to be employed as part of the Proposed Action is Brodifacoum-25D Conservation, a pelleted rodenticide bait intended for conservation purposes for the control or eradication of invasive rodents on islands or vessels. Bait application is currently being considered for Summer 2019. Sand Island is one of three islands comprising the MANWR, which is part of the PMNM in the Northwestern Hawaiian Islands (NWHI) (see Figure 1 and 2). The Papahanaumokuakea Monument Management Plan (PMMP) completed in December 2008 identified six priority management needs, with supporting action plans and corresponding desired outcomes for the PMNM (Service 2008). A specific component of Priority 3, Reducing Threats to Monument Resources, was the development of an Alien Species Action Plan (ASAP). Specifically, the ASAP identified the eradication of the house mouse on Sand Island, Midway Atoll as Strategy AS-4 (see Table 1). Figure 1 Location Map of Main Hawaiian Islands, the Northwestern Hawaiian Islands Archipelago, the Papahanaumokuakea Marine National Monument Boundary, and Midway Atoll. source: https://www.papahanaumokuakea.gov/visit/ (2017) Midway Seabird Protection Project - 01EPIF00-2019-F-0049 4 Figure 2. Midway Atoll National Wildlife Refuge (MANWR) and Location of Sand, Eastern and Spit Islands. Source: Planning Solutions, Inc. and Hamer Environmental (2017) Eradicating the invasive house mouse from Sand Island and subsequently maintaining a rodent- free status for the island in perpetuity requires implementation of Strategy AS-4 from the PMMP. To eradicate invasive mice, a lethal dose of rodenticide will be delivered to every rodent on the island in a manner that minimizes harm to island residents and the ecosystem while still maintaining a high probability of successful eradication. Implementing Strategy AS-4 constitutes a federal agency action that may have an impact on threatened and endangered species, and critical habitats of Sand Island. Midway Seabird Protection Project - 01EPIF00-2019-F-0049 5 Table 1. Strategy AS-4 of the PMMP Strategy AS-4: Eradicate the house mouse population on Sand Island, Midway Atoll, within 15 years. After the eradication of the black rat (Rattus rattus) at Midway Atoll and the Polynesian rat (Rattus exulans) at Kure Atoll, the house mouse on Sand Island, Midway, remains the only invasive mammal left in the NWHI. Mice can cause high mortality in seabirds as large as albatrosses (Wanless et al. 2007). In addition, Midway now hosts a translocated population of endangered Laysan ducks that are likely to be negatively affected by the high mouse populations. Mice are also a threat to native plants and terrestrial invertebrates. Activity AS-4.1: Produce a house mouse eradication plan within 5 years and procure appropriate permits for chosen eradication techniques. The eradication of introduced rodents from islands is routine, and the successful removal of black rats at Midway Atoll in recent years has provided a model for mouse eradication. Mice present additional challenges, however, as they have much smaller home range sizes and different foraging and reproductive ecology. A careful planning effort that emphasizes the minimization of effects to non-target organisms at the site and the other biological differences that may affect the operation is necessary. Activity AS-4.2: Implement and complete house mouse eradication. All of Sand Island 1,128 acres (ac.) (456 hectares (ha.)) will be treated with rodenticide, with active management to prevent non-target impacts to native wildlife. Surveys of the affected ecosystem components before and after the operation will provide a valuable demonstration of the effects of introduced mice on biological communities. Source: Alien Species Action Plan, Papahanaumokuakea Monument Management Plan (Service 2008) PROJECT BACKGROUND The impacts from invasive predatory mammals, including mice and rats, are one of the leading causes of species extinction on islands (Blackburn et al. 2004; Duncan and Blackburn 2007). Over three million birds, encompassing 25 different species, can be found at MANWR and all of them are susceptible to predation by mice. The federally endangered Laysan duck population is important because