Avian species are in rapid decline worldwide, with 1 in 8 species facing extinction, and in North America shorebird species are declining at a higher proportion than other groups. The nearshore ecosystem in Maine (USA) supports several bird species that rely on intertidal and subtidal zones, including high densities of migratory shorebirds and wintering waterfowl. Additionally, Acadia National Park (ANP) includes some of the country’s highest densities of declining populations of Purple Sandpipers (Calidris maritima) and state threatened Harlequin Ducks (Histrionicus histrionicus). We investigated whether the distribution of candidate umbrella species overlapped with the distribution of 5 waterfowl taxa (Common Eiders [Somateria mollissima], Long-tailed Ducks [Clangula hyemalis], Black Scoters [Melanitta americana], Bucephala spp., and Mallards [Anas platyrhynchos]), thereby examining whether conservation actions (e.g., conservation closures) taken to preserve these 2 species of high conservation concern might also benefit the larger taxonomic groups to which they belong, a concept known as umbrella species conservation. To answer this question, bird abundance surveys were conducted within ANP during 2021 and 2022, and detection and occupancy were compared among the focal groups using a hypothesis-driven model. The occupancy distributions of our 5 waterfowl taxa revealed that sites with the highest occupancy estimates for Common Eiders, Long-tailed Ducks, and Black Scoters included sites occupied by Purple Sandpipers and Harlequin Ducks. Bucephala spp. and Mallard occupancy, however, only weakly overlapped with our candidate umbrella detections, occurring in sites with the lowest and mid-range occupancy estimates. Thus, any positive effect of conservation closures based on these 2 species of concern might impact some, but not all, species we surveyed. Including more survey locations occupied by Purple Sandpipers and Harlequin Ducks would be necessary to see if this pattern is generalizable across the region. Our low sample size for umbrella species detections, however, also highlights the limited utility of using rare species as umbrellas.

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