Over the past century, one of the international community’s primary objectives has been environmental conservation.[1] Through the power of international law, nations and international organizations have drafted and implemented agreements aimed at protecting the planet and its many inhabitants.[2] One subset of international environmental conservation, however, has received relatively little attention: bird conservation. The conservation of the world’s birds has not received the same level of attention as other environmental issues, such as climate change and water resources management.[3] Nevertheless, international law does provide measures for bird conservation and often serves as the foundation for effective global efforts to protect bird species, such as international conventions and treaties aimed at protecting migratory birds.[4] In fact, international cooperation—guided by international law—is essential for the effective conservation and management of bird populations. Domestic measures alone are often inadequate to effectively manage extensive, migratory bird populations, and lack the adaptability needed to address both present and future challenges these species face.
The legal basis for international bird conservation emerged in the early 1900s, when national efforts proved inadequate to address the growing problem of excessive bird hunting. By the early 1900s, commercial hunting of birds, particularly migratory species, was rampant; hunters, unburdened by any regulations, killed birds for their feathers and for sport, leading many species to become extinct or near-extinct, such as the Passenger Pigeon and the Carolina Parakeet.[5] Congress recognized the need for federal regulation, and in 1913, Congress passed the Weeks-McClean Act (“the Act”),[6] which “declared that birds were ‘within the custody and protection’ of the United States (“U.S.”) and that it was unlawful to shoot them except in accordance with regulations to be promulgated by the Secretary of Agriculture.”[7] However, the Weeks-McClean Act was soon subjected to constitutional scrutiny, with arguments asserting that it exceeded the powers granted to Congress as the Constitution did not give Congress the power to regulate hunting activity.[8] In United States v. Shauver,[9] a U.S. District Court found that there was no provision in the Constitution authorizing Congress to adopt the Weeks-McClean Act, and other courts echoed the same sentiment.[10] Without an explicit clause or implicit power in the Constitution authorizing Congress to regulate hunting, any law it made to regulate the practice would be considered unconstitutional, and thus inoperable. With an appeal pending before the U.S. Supreme Court, it seemed likely that the Act would be struck down.[11] When the case got to the Supreme Court in 1919, however, the Court dismissed the case in error.[12]
The story of international bird conservation began as a constitutional strategy for Congress to justify its regulation.[13] The birds Congress sought to protect were migratory, regularly traversing international borders; thus, any effort to protect birds needed to originate in the United States’ international relations. In 1918, Congress exercised its explicit power to implement treaties made by the President (found under the Article II provision stating that the President can make treaties “with the advice and consent of the Senate”) by passing the Migratory Bird Treaty Act (“MBTA”).[14] The Act complemented Canada’s Migratory Birds Convention Act[15] by giving effect to the convention between the U.S. and Canada, which aimed to protect migratory birds, their eggs, and their feathers from hunting and commercial exploitation.[16] The Act survived constitutional scrutiny in Missouri v. Holland,[17] thus establishing the framework of international law as a valid mechanism for bird conservation.[18] As the Supreme Court upheld the MBTA as a constitutional environmental regulation due to its international components, those components came to define how bird conservation could be achieved, both domestically and abroad.
The MBTA’s international components are central to the U.S.’ bird conservation efforts; many of the U.S.’s bird conservation efforts involve cooperation with other nations.[19] Since 1918, it has been amended to incorporate additional bird conservation conventions with other nations.[20] It was amended to include the agreements with Mexico in 1936, Japan in 1972, and Russia in 1976.[21] These agreed-upon international objectives and enforcement mechanisms became an “integral part of domestic federal law,” being enforced and administered by U.S. agencies like the U.S. Fish and Wildlife Service.[22]
This framework has been effectively employed in the conservation and management of migratory bird populations. In North America, international cooperation between Canada, the United States, and Mexico forms the centerpiece of the North American Waterfowl Management Plan, which serves to “restore [migratory waterfowl populations] through habitat protection, restoration and enhancement” through “regional partnerships called migratory bird joint ventures.”[23] One such venture is the Arctic Goose Joint Venture (“AGJV”).[24] The AGJV represents the pinnacle of international cooperation aimed at supporting migratory birds; it facilitates research, monitoring, and communications for seven species and twenty-four populations of geese that breed in the Arctic and migrate throughout [North America],” funding projects that monitor different goose populations and their habitats.[25] This research and monitoring are subsequently used to support localized research, such as reports on the population of migratory game birds[26] and to inform consistent management decisions across jurisdictions, such as hunting regulations.[27]
Another example of international cooperation is the Initiative for Central Asian Flyway (“ICAF”).[28] In 2024, thirty Asian countries, including Afghanistan, China, Nepal, Saudi Arabia, and Sri Lanka, adopted the ICAF to coordinate regional cooperation in managing the Central Asian Flyway.[29] The Central Asian Flyway is a network of migration routes across Asia used by over 180 species of waterfowl, including many threatened species, as they migrate between their wintering and breeding grounds.[30] The Convention on Migratory Species identified that “[t]here is an urgent need for science-based and internationally coordinated conservation measures, ensuring the survival of species and their habitats as well as sustainable benefits to people;” such dangers to migratory birds in the region include “uncontrolled hunting, habitat degradation, unsustainable water management, and lack of law enforcement and conservation capacity.”[31] ICAF calls for the development of plans to facilitate the implementation of decisions adopted by the Convention, and it also “enhance[s] and facilitate[s] communication and information sharing between the CAF Range States [thirty Central and South Asian and Middle Eastern nations],” encouraging action at both the international and domestic levels to effectively manage the Central Asian Flyway.[32] Coordination of resources and conservation efforts is essential to the development of a consistently-applied management scheme. If plans are not consistently enforced along the CAF, the ability to protect birds diminishes as there are ultimately gaps of under-protection of birds and under-enforcement of the law.
Both the AGJV and ICAF emphasize the communication of information and data to coordinate consistent management strategies among states.[33] Due to the nature of migratory birds, such communication and cooperation are essential for successful management. Migratory birds do not recognize the borders defined by the international community; they routinely cross many borders during their migrations. Without coordinated international management, domestic practices would vary substantially, subjecting the same birds to different levels of protection and care.[34] One state’s management practices and motives could be severely undermined by another state’s failure to protect the same birds. For example, on the island of Cyprus, poaching of migratory songbirds has increased due to the Republic of Cyprus’s lax enforcement of conservation laws; this is in contrast to the law enforcement present in the Turkish and British-controlled parts of the island, which undermines the conservation efforts of the region.[35] In other words, attempts to manage migratory birds state-to-state are ineffective due to a lack of communication and cooperation, which results in inconsistent management practices. It is these essential factors—communication and cooperation—that the model of international bird conservation, established by the MBTA, rightly emphasizes.
Unfortunately, it is inaccurate to suggest that this model is completely successful in managing bird populations worldwide. While international cooperation has undoubtedly proven effective in addressing past challenges, namely poaching and other illicit exploitation activities, the future presents challenges that current agreements fail to adequately address. According to a United Nations (“UN”) report, “nearly half of the world’s migratory species are in decline, and more than twenty percent are threatened with extinction,” with most of those species being birds.[36] This stark figure can be explained by a disconnect between the threats the model was originally meant to address and the threats migratory birds face today.
The MBTA, like its predecessor the Weeks-McClean Act, was primarily drafted to address the issues of overhunting and overexploitation of birds that were prevalent at the time.[37] The language of the statute explicitly makes it a crime to “hunt, take, capture, [or] kill” regulated birds, as well as criminalizes the sale or barter of them, their feathers, or their eggs.[38] Moreover, even modern agreements, such as the AGJV, still maintain at least a partial focus on hunting.[39] The AGJV, for example, addresses “maintaining healthy goose populations for subsistence and recreational harvest . . . .”[40] Though undoubtedly still a threat to bird populations across the world, hunting and overexploitation do not present the principal threat to birds today.
According to the UN report, “habitat loss, degradation and fragmentation represent the most common threat affecting CMS-listed species as a whole . . . .”[41] While overexploitation remains a significant threat, the primary threats to birds have shifted from direct harms, such as overhunting and overexploitation, to indirect ones—those caused as byproducts of human economic or industrial activity.[42] Moreover, climate change presents its own set of threats to birds, while also exacerbating the issues of habitat loss, degradation, and fragmentation caused by human activity.[43] Many existing regulations and agreements fail to address these indirect harms, producing a significant gap in what kinds of harm bird conservation efforts focus on.
The focus of future agreements must shift. While addressing overexploitation remains important, it is imperative that future agreements tackle habitat loss and degradation, driven by both human activity and climate change. The key takeaway, illustrated by a century of treaties, joint ventures, initiatives, and agreements, is that international cooperation, underpinned by international law, must remain the foundation for shaping the future of global bird conservation.
[1] See About the United Nations Environment Programme, United Nations Environment Programme (last visited Apr. 18, 2025), https://www.unep.org/who-we-are/about-us.
[2] See, e.g., Montreal Protocol on Substances that Deplete the Ozone Layer, Sept. 16, 1987, 1522 U.N.T.S. 29.
[3] See Climate Action, United Nations Environment Programme (last visited Apr. 18, 2025), https://www.unep.org/topics/climate-action. But cf. Nature Action, United Nations Environment Programme (last visited Apr. 18, 2025), https://www.unep.org/topics/nature-action.
[4] See infra notes 15, 21, 24.
[5] The Migratory Bird Treaty Act, Explained, National Audubon Society (Jan. 28, 2018), https://www.audubon.org/news/the-migratory-bird-treaty-act-explained; Jesse Greenspan, The History and Evolution of the Migratory Bird Treaty Act, National Audubon Society (May 22, 2015), https://www.audubon.org/news/the-history-and-evolution-migratory-bird-treaty-act.
[6] Act of March 4, 1913, ch. 145, 37 Stat. 847 (1913).
[7] George Cameron Coggins & Sebastian T. Patti, The Resurrection and Expansion of the Migratory Bird Treaty Act, 50 U. Colo. L. Rev. 165, 169 (1979).
[8] Id.
[9] United States v. Shauver, 214 F. 154 (E.D. Ark. 1914).
[10] Memorandum from the Principal Deputy Solic. to the Sec’y of the Interior (Dec. 22, 2017) (on file with the Dep’t of the Interior).
[11] Id.
[12] United States v. Shauver, 248 U.S. 594, 595 (1919).
[13] Coggins, supra note 7, at 169.
[14] Id.; 16 U.S.C. § 703.; U.S. Const. art. II, § 2.
[15] Migratory Birds Convention Act, S.C. 1994, c 22 (Can.).
[16] Migratory Birds Convention Act, S.C. 1994, c 22 (Can.); 16 U.S.C. § 703(a).
[17] Missouri v. Holland, 252 U.S. 416 (1920).
[18] Coggins, supra note 7, at 169.
[19] See infra notes 23 and 24.
[20] § 703(a).
[21] Id.
[22] Coggins, supra note 7, at 174.
[23] North American Waterfowl Management Plan, U.S. Fish and Wildlife Service (last visited Mar. 31, 2025), https://www.fws.gov/partner/north-american-waterfowl-management-plan.
[24] See Fact Sheet, Arctic Goose Joint Venture (Jan. 2024), https://www.agjv.ca/wp-content/uploads/2024/02/AGJV-Fact-Sheet-January-2024.pdf; Arctic Goose Joint Venture: A Prospectus, North American Waterfowl Management Plan (1991).
[25] Fact Sheet, supra note 24.
[26] See Population Status of Migratory Game Birds in Canada, Canadian Wildlife Service Waterfowl Committee (Nov. 2017), https://publications.gc.ca/collections/collection_2018/eccc/CW69-16-49-2018-eng.pdf.
[27] Fact Sheet, supra note 24.
[28] Convention on Migratory Species Res. 14.13, at 1-3 (Feb. 17, 2024).
[29] Id.
[30] Central Asian Flyway, Convention on Migratory Species (last visited Mar. 31, 2025), https://www.cms.int/en/legalinstrument/central-asian-flyway.
[31] Id.
[32] C.M.S. Res. 14.13, supra note 28, at 4.
[33] See Fact Sheet, supra note 24; C.M.S. Res. 14.13, supra note 28, at 3-4.
[34] See Rachel Nuwer, The Migrant Trap, Audubon, Summer 2024, at 51, 53.
[35] Id. at 51, 53-54.
[36] Nat Seavy, UN Report Finds Many Migratory Species in Existential Peril, Audubon (Mar. 14, 2024), https://www.audubon.org/news/un-report-finds-many-migratory-species-existential-peril.
[37] Coggins, supra note 7, at 169.
[38] 16 U.S.C. § 703(a).
[39] Fact Sheet, supra note 24.
[40] Id.
[41] Convention on the Conservation of Migratory Species of Wild Animals, State of the World’s Migratory Species, at 26 (Feb. 2024).
[42] Id. at 26, 29.
[43] Id. at 34.
