S. 310 would authorize the appropriation of $6.5 million annually over the 2020-2024 period for the U.S. Fish and Wildlife Service (USFWS) to provide grants for the conservation of neotropical migratory birds. In 2018, the USFWS received an appropriation of $4 million for that purpose. Based on historical spending patterns, CBO estimates that implementing S. 310 would cost $29 million over the 2019-2024 period and $4 million after 2024, assuming appropriation of the authorized amounts.