Metals in tissues of migrant semipalmated sandpipers (Calidris pusilla) from Delaware Bay, New Jersey

2014 ◽  
Vol 133 ◽  
pp. 362-370 ◽  
Author(s):  
Joanna Burger ◽  
Michael Gochfeld ◽  
Lawrence Niles ◽  
Amanda Dey ◽  
Christian Jeitner ◽  
...  
2018 ◽  
Vol 96 (9) ◽  
pp. 996-1001 ◽  
Author(s):  
Ivana Novcic ◽  
Guy Beauchamp

We examined the influence of the density of foragers on feeding rates of Semipalmated Sandpipers (Calidris pusilla (Linnaeus, 1766)) while using different foraging modes at a spring stopover site in Delaware Bay, USA. Using dynamic estimates of interindividual distances obtained at short intervals of time, we explored how forager density affected feeding rates when Semipalmated Sandpipers used visual pecking or tactile probing. Pecking rate significantly increased with interindividual distances, whereas probe rate was not affected by density. Our study also showed that in fast-moving foragers, such as Semipalmated Sandpipers, in which the number of nearby foragers and distance to the nearest neighbour continuously change throughout the foraging bout, pecking rates are more affected by nearest neighbour distance than by the number of foragers in their immediate vicinity. In addition, our study implies that foragers using different foraging modes might be differently affected by nearby competitors perhaps in response to prey disturbance by neighbours.


1995 ◽  
Vol 22 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Joanna Burger ◽  
Michael Gochfeld ◽  
Larry J. Niles

People of diverse cultures appreciate and observe wildlife. With the increase in the importance of economic, social, and aesthetic, values of wildlife comes the responsibility for wise management and use of these resources to ensure biodiversity and the continued wellbeing of the populations. We describe several ways in which ecotourists affect the behaviour, reproductive success, and population levels, of breeding and migratory birds in New Jersey — a heavily industrialized, coastal US state with a dense human population. We use several case-studies to illustrate the effects of ecotourists on birds: heronries, breeding Least Terns (Sterna antillarum), foraging Piping Plovers (Charadrius melodus) during the breeding season, migrant shorebirds and gulls at Caven Point and Delaware Bay, and migrant hawks at Cape May.


The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1397-1406 ◽  
Author(s):  
Susan M. Rice ◽  
Jaime A. Collazo ◽  
Mathew W. Alldredge ◽  
Brian A. Harrington ◽  
Allen R. Lewis

Abstract We report seasonal residency and local annual survival rates of migratory Semipalmated Sandpipers (Calidris pusilla) at the Cabo Rojo salt flats, Puerto Rico. Residency rate (daily probability of remaining on the flats) was 0.991 ± 0.001 (x̄ ± SE), yielding a mean length of stay of 110 days. This finding supports the inclusion of the Caribbean as part of the species' winter range. Average estimated percentage of fat was low but increased throughout the season, which suggests that birds replenish some spent fat reserves and strive for energetic maintenance. Local annual survival rate was 0.62 ± 0.04, within the range of values reported for breeding populations at Manitoba and Alaska (0.53–0.76). The similarity was not unexpected because estimates were obtained annually but at opposite sites of their annual migratory movements. Birds captured at the salt flats appeared to be a mix of birds from various parts of the breeding range, judging from morphology (culmen's coefficient of variation = 9.1, n = 106). This suggested that origin (breeding area) of birds and their proportion in the data should be ascertained and accounted for in analyses to glean the full conservation implications of winter-based annual survival estimates. Those data are needed to unravel the possibility that individuals of distinct populations are affected by differential mortality factors across different migratory routes. Mean length of stay strongly suggested that habitat quality at the salt flats was high. Rainfall and tidal flow combine to increase food availability during fall. The salt flats dry up gradually toward late January, at the onset of the dry season. Semipalmated Sandpipers may move west to other Greater Antilles or south to sites such as coastal Surinam until the onset of spring migration. They are not an oversummering species at the salt flats. Conservation efforts in the Caribbean region require understanding the dynamics of this species throughout winter to protect essential habitat. Tasas de Supervivencia Anual Local y de Residencia Estacional de Calidris pusilla en Puerto Rico


1989 ◽  
Vol 67 (2) ◽  
pp. 457-462 ◽  
Author(s):  
J. Sherman Boates ◽  
Peter C. Smith

During late spring and summer, the crawling behaviour of the amphipod Corophium volutator was studied on an intertidal mudflat in the Minas Basin, Nova Scotia. On average, less than 1% of the population crawled on any tide and these individuals tended to be large adults that were predominantly males. Animals emerged as the tide receded but most had crawled into burrows after 25 min. The crawling behaviour did not seem to be related to the lunar cycle as was expected; however, there was a sharp reduction in crawling activity (from 36.3 to 1.2 amphipods/m2) in July that coincided with the arrival of Semipalmated Sandpipers, Calidris pusilla, an abundant seasonal predator. The proportion of males in the amphipod population declined during the period when sandpipers were present. It appears that both a change in amphipod behaviour and depletion of the animals most prone to crawling may contribute to the observed reduction in crawling activity. Qualitative and quantitative evidence show that sandpipers were attracted to the tide edge where crawling amphipods were relatively abundant and that they increased their food intake by doing so.


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