Robert W. Elner

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We report that a latitudinal cline in intertidal food distribution is associated with the nonbreeding distribution of the Western Sandpiper (Calidris mauri). This novel result is the first to demonstrate a clear relationship between patterns of differential nonbreeding distribution and food availability for any shorebird species. Within each age class and(More)
Migrating Western Sandpipers, Calidris mauri (Cabanis, 1857), observed feeding at an intertidal stopover site on the Fraser River delta, British Columbia, shifted their foraging mode from surface-pecking to probing over a 3week period in April and May. We tested possible mechanisms to account for the field observations. Using control and shorebird exclusion(More)
We show that a higher vertebrate can graze surficial intertidal biofilm, previously only considered a food source for rasping invertebrates and a few specialized fish. Using evidence from video recordings, stomach contents, and stable isotopes, we describe for the first time the grazing behavior of Western Sandpipers (Calidris mauri) and estimate that(More)
—Western Sandpipers and Dunlin are capable of grazing biofilm. As there has been no assessment of this dietary constituent in stomach contents, the stomachs of 89 Western Sandpipers and 56 Dunlin collected during breeding migration through the Fraser River delta, British Columbia, Canada, were examined. Invertebrates, traditionally regarded as the principal(More)
Mechanical aspects of predation by the shore crab, Carcinus maenas, on the edible mussel, Mytilus edulis, were examined. The shore crabs from the population studied utilized five distinct, largely size-related, mussel-opening techniques. Crushing the mussel umbone appeared the most successful opening method for medium-sized prey. Small mussels were crushed(More)
Western sandpipers (Calidris mauri (Cabanis, 1857)) exhibit slight female-biased sexual size dimorphism (5%) but disproportionate bill length dimorphism (15.9%). We test two predictions of the niche differentiation hypothesis at two wintering sites in Mexico with uniform western sandpiper densities, and use sex ratio as an index of intersexual competition.(More)
Food webs are comprised of a network of trophic interactions and are essential to elucidating ecosystem processes and functions. However, the presence of unknown, but critical networks hampers understanding of complex and dynamic food webs in nature. Here, we empirically demonstrate a missing link, both critical and variable, by revealing that direct(More)
Trace element concentrations were measured in Pacific Dunlin (Calidris alpina pacifica) to identify factors that influence accumulation and to assess toxicity risks. We report concentrations of cadmium, copper, and zinc in kidneys as well as copper, lead, mercury, selenium and zinc in feathers. Relationships between element concentrations and Dunlin age,(More)
Coastal landscapes with extensive intertidal mudflats provide non-breeding habitat for Arctic shorebirds. Few attempts have been made to develop and test landscape-level models predicting the intertidal distribution of these birds. We modelled the distribution of a Holarctic species, Dunlin (Calidris alpina), at a hemispherically important non-breeding(More)
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