• Brown, L.A., T. MacLaurin, E. Levine-Barnoff, S. Banerjee and E. Nol. In press. American Oystercatchers (Haematopus palliatus) support a foraging commensalism for Ruddy Turnstones (Arenaria interpres) and Sanderlings (Calidris alba). Waterbirds.

    We documented a facultative foraging commensalism that American Oystercatchers (Haematopus palliatus) support for Ruddy Turnstones (Arenaria interpres) and Sanderlings (Calidris alba) during their spring and fall migrations through coastal Virginia, U.S.A. Some breeding American Oystercatchers strip eggs from mole crabs (Emerita talpoida) and then discard the carapaces and remaining flesh. We made 179 observations of Ruddy Turnstones and Sanderlings following American Oystercatchers, to eat discarded carapaces. More Ruddy Turnstones (x̄ = 2.48 ± 0.29 (SE) and Sanderlings (4.64 ± 1.24) followed a foraging American Oystercatcher in spring than in fall (Ruddy Turnstones: 1.25 ± 0.25, Sanderlings: 3.67 ± 0.62), perhaps reflecting pressure to minimize stopover duration and refuel quickly to reach the breeding grounds. American Oystercatchers supported a stronger foraging commensalism for Ruddy Turnstones, who increased mole crab consumption by 15 times in the presence of an egg-stripping American Oystercatcher, compared to an increase of 1.4 times for Sanderlings. Ruddy Turnstones were more aggressive foragers, pursuing egg-stripping American Oystercatchers, while Sanderlings opportunistically took nearby discards. Mole crab egg stripping by American Oystercatchers provides an easily accessible food source that supplements diets of Ruddy Turnstones and Sanderlings.

  • Brown, L.A., T. MacLaurin, A. May & E. Nol. In press. A visual sexing technique for American Oystercatchers (Haematopus palliatus) suitable for the field. Waterbirds.

    There is no published method for visually sexing American Oystercatchers (Haematopus palliatus) in the field without having the bird in-hand or using expensive telephoto equipment. This study describes and verifies the accuracy of a method requiring only binoculars or a spotting scope to sex American Oystercatchers by dimorphism in body size, bill length, bill color, and back plumage. From 2023–2024, 50 individuals breeding in Virginia, U.S.A. were visually assigned a sex in the field. After capture, DNA testing confirmed the visually assigned sex in 98% of cases. To further validate the method, in 2024, 27 of these birds (14 males, 13 females) were captured, photographed to record back plumage and bill color and measured. Photos were color-analyzed using ImageJ. Males had significantly darker backs, with shorter, darker red bills and smaller bodies. There was 100% sexing classification accuracy using these colormetrics and morphometrics. Photography techniques and ImageJ analysis had been previously verified using 23 American Oystercatcher museum specimens (8 males and 15 females). This visual technique provides an easy, cost-effective way to discriminate the sexes. It might be applied to enrich breeding productivity data collection and identify sex-specific behaviors and life history strategies.

  • MacLaurin, T., L.A. Brown & E. Nol. 2026. Influence of Vegetation and Elevation on Nest-Site Selection and Reproductive Success in American Oystercatchers (Haematopus palliatus). Waterbirds, 48(3): 1-10.

    https://doi.org/10.1675/063.048.0310

    Barrier island habitats are increasingly threatened by climate change, with potential consequences for the breeding success and habitat quality of beach-nesting birds. Understanding fine-scale habitat requirements is important for identifying risks and managing these environments to support reproductive success. We evaluated two key habitat features, vegetation density and elevation, to understand their influence on American Oystercatcher (Haematopus palliatus) nest-site selection, hatching success, and fledging success on two Virginia (U.S.A.) barrier islands (Assateague and Assawoman Island). Using long-term nest monitoring data (2007–2022) and three years of remotely sensed elevation and vegetation data (2015, 2016, and 2021), we found that American Oystercatchers consistently preferred nest sites with lower vegetation density and at higher elevation. However, neither factor predicted hatching or fledging success. These results suggest that vegetation encroachment may contribute to population declines not by reducing reproductive output directly, but by limiting the availability of suitable nesting habitat. Vegetation nonetheless plays a key role in stabilizing high-elevation dune systems. Effective beach management should prioritize the preservation and creation of sparsely vegetated, elevated sites to maintain nest-site availability under changing coastal conditions.

  • MacLaurin, T. 2026. Un-brie-lievable: A cheese-eating Eurasian Oystercatcher Haematopus ostralegus. Wader Study 133(1): 50-52.

    https://doi.org/10.18194/ws.00397

    In the Faroe Islands, a pair of Eurasian Oystercatchers has visited the same doorstep every spring and summer for four years to ask for mozzarella, and has even fed it to their chicks. This note is the first formal description of a shorebird repeatedly using processed human food, and raises questions about how urban living is changing the behaviour of these birds.