Western Sandpipers Calidris Mauri Research Articles

Use of semi-intensive shrimp farms as alternative foraging areas by migratory shorebird populations in tropical areas

SummaryEvaluating the ability of anthropogenic habitats to serve as surrogates for natural habitats is an increasingly relevant issue in conservation biology. This issue is especially urgent in tropical coastal wetlands that support large concentrations of migratory shorebird populations and are under pressure from development. Here we evaluated the species composition, abundance, and habitat use of Nearctic migratory shorebirds using recently harvested aquaculture ponds during two non-breeding seasons at shrimp farms surrounding Bahía Santa María (BSM), northwestern Mexico. We also estimated shorebird densities at intertidal units in BSM during and after the harvesting season to explore the connectivity with shrimp farms. Over 25,000 individuals of 25 shorebird species used the surveyed farms (∼13% of shrimp-farm development in BSM; 2014–2015: 10 farms, 994 ha; 2015–2016: 8 farms, 924 ha) during the harvest season. The most abundant species were: Western Sandpiper Calidris mauri, Willet Tringa semipalmata, Marbled Godwit Limosa fedoa, dowitchers Limnodromus spp., Black-necked Stilt Himantopus mexicanus and American Avocet Recurvirostra americana. Numbers of birds decreased as the harvest cycle progressed. Most birds (> 70%) were foraging on the ponds, regardless of tidal stage, while numbers increased during high tide for the most abundant species. At surveyed intertidal areas, shorebird densities were overall similar within and between non-breeding seasons. These results indicate that shrimp farms offer ephemeral but consistent foraging habitats used by non-breeding shorebirds, even in vast coastal wetlands offering a high availability of natural intertidal mudflats. Assuming a similar shorebird use in other shrimp ponds not surveyed within BSM, a significant proportion (> 1% of the biogeographic population) of Willet, Marbled Godwit, and Western Sandpiper, as well as imperilled Red Knot Calidris canutus, might use shrimp farms throughout the harvesting season. Before including current semi-intensive shrimp farms within management plans of BSM, further research is mandatory to assess their utility as alternative foraging habitats for shorebird conservation at tropical areas.

Range‐wide patterns of migratory connectivity in the western sandpiper Calidris mauri

Understanding the population dynamics of migratory animals and predicting the consequences of environmental change requires knowing how populations are spatially connected between different periods of the annual cycle. We used stable isotopes to examine patterns of migratory connectivity across the range of the western sandpiper Calidris mauri. First, we developed a winter isotope basemap from stable‐hydrogen (δD), ‐carbon (δ13C), and ‐nitrogen (δ15N) isotopes of feathers grown in wintering areas. δD and δ15N values from wintering individuals varied with the latitude and longitude of capture location, while δ13C varied with longitude only. We then tested the ability of the basemap to assign known‐origin individuals. Sixty percent of wintering individuals were correctly assigned to their region of origin out of seven possible regions. Finally, we estimated the winter origins of breeding and migrant individuals and compared the resulting empirical distribution against the distribution that would be expected based on patterns of winter relative abundance. For breeding birds, the distribution of winter origins differed from expected only among males in the Yukon‐Kuskokwim (Y‐K) Delta and Nome, Alaska. Males in the Y‐K Delta originated overwhelmingly from western Mexico, while in Nome, there were fewer males from western North America and more from the Baja Peninsula than expected. An unexpectedly high proportion of migrants captured at a stopover site in the interior United States originated from eastern and southern wintering areas, while none originated from western North America. In general, we document substantial mixing between the breeding and wintering populations of both sexes, which will buffer the global population of western sandpipers from the effects of local habitat loss on both breeding and wintering grounds.

Downward trophic shift during breeding migration in the shorebird Calidris mauri (western sandpiper)

The recent demonstration of mudflat surficial biofilm feeding by western sandpiper Calidris mauri has provided new insight into the feeding ecology of shorebirds. We assessed feeding modes over the migratory cycle, and specifically whether a downward shift in trophic position occurred during the 2004 northward migration from their overwintering areas to the Arctic breeding grounds. We used stable isotope composition and calculated trophic positions of adult western sand- piper at their northward migratory stopover on Roberts Bank, British Columbia, Canada, in 3 animal compartments with increasing turnover times (stomach contents, liver, and muscle). This allowed the retrospective determination of their major diet source types over time frames encompassing the geo- graphical ranges of their previous migratory stopovers and arrival on the Roberts Bank stopover. Detailed taxonomic and photopigment determinations were also performed on stomach contents and surficial biofilm. The Roberts Bank biofilm showed high taxonomic homogeneity among sampling sites, suggesting a qualitatively consistent food source during western sandpiper stopover. A statisti- cally significant downward shift in mean trophic position (TP) occurred between previous migratory stopovers (TP = 3.0 ± 0.5, mean ± SD) and arrival on the Roberts Bank stopover, where the maximum probability densities showed >70% dietary contribution of benthic diatoms, with a TP = 2.3 ± 0.4, close to the diet of the suspension-feeding bivalves Tapes philippinarum and Mya sp. (TP = 2). Advantages of biofilm over macrofaunal feeding during migration may include decreased handling and search time, as well as greater availability and digestibility of the high-energy carbohydrates needed for flight.

Sjeldne fugler i Norge i 2008 - Rapport fra Norsk sjeldenhetskomité for fugl (NSKF)

This is the 33rd annual report from the Norwegian Rarities Committee (NSKF). The majority of records treated here are from 2008, but more than 100 older records are also included. The Norwegian rarities committee follow advises given by the Taxonomic Advisory Committee (TAC) of the Association of European Records and Rarities Committees (AERC) on issues concerning taxonomy and nomenclature. The systematic list of accepted records is set out in the following system: (1) The bird's Norwegian name, (2) scientific name, (3) the numbers in brackets, e.g. (2, 30/32, 1), refers respectively to the (i) total number of records/total number of individuals up to and including 1974, (ii) total number of records/total number of individuals from 1975 (the foundation year of NSKF), except (iii) records/individuals in 2008, (4) any breeding, (5) year, (6) county, (7) number of individuals, age (1K = first calendar year etc.), sex (if known) and sometimes circumstances («rm.» means that the bird was ringed, «sy.» indicates a singing male), (8) site and municipality, (9) date, (10) * indicates if the record was complemented by positive evidence, and type of the evidence (F = photo, V = video-recorded, L = tape-recorded), (11) observers' names in brackets, main observer(s) is specified first and emphasized with *, (12) roughly gives the species' distribution and (13) comments concerning the records.Species and subspecies new to the Norwegian listTwo new species were accepted to the Norwegian Category A list from 2008. Both of these were Nearctic waders, namely a Hudsonian Godwit Limosa haemastica from Røstlandet on June 24th and a Western Sandpiper Calidris mauri from Jæren on July 12th-13th. In addition there were three new subspecies accepted: Buff-bellied Pipit Anthus rubescens japonicus (Karmøy, January to April), Yellow Wagtail Motacilla flava feldegg (Utsira, 3rd to 5th June) and White Wagtail M. alba leucopsis (Lista, 1st-2nd November).General trendsRecord numbers for Norway was recorded for Grey Phalarope Phalaropus fulicarius (14/23) during 2008. Also the following species showed an occurrence above average during 2008: Great White Egret Ardea alba, Black Kite Milvus migrans, Pectoral Sandpiper C. melanotos, Red-rumped Swallow Cecropis daurica, Citrine Wagtail M. citreola, Blyth's Reed Warbler Acrocephalus dumetorum and Rose-coloured Starling Sturnus roseus. Also published here are the 6th Egyptian Goose Alopochen aegyptiaca (Cat. C), 3rd Lesser Scaup Aythya affinis, 8th Harlequin Duck Histrionicus histrionicus, 5th to 7th American Golden Plover Pluvialis dominica, 4th Laughing Gull Larus atricilla, 6th Franklin's Gull L. pipixcan, 6th and 8th Oriental Turtle Dove Streptopelia orientalis, 8th Blyth's Pipit A. godlewskii, 2nd Siberian Rubythroat Luscinia calliope, 5th Isabelline Wheatear Oenanthe isabellina, 10th Lanceolated Warbler Locustella lanceolata, 4th Melodious Warbler Hippolais polyglotta, 3rd Eastern Bonelli's Warbler Phylloscopus orientalis and 4th and 7th Steppe Grey Shrike Lanius meridionalis pallidirostris.

Surface tension prey transport in shorebirds: how widespread is it?

Surface tension prey transport is a feeding mechanism employing the surface tension of water surrounding prey to transport prey from bill tip to mouth. Previously, it has been demonstrated only in the Red‐necked Phalarope Phalaropus lobatus. On the basis of a model of the bill morphology necessary for this method of prey transport, I suggest that many species of shorebird should be capable of surface tension feeding. Laboratory investigations of the feeding mechanics of Wilson's Phalarope Phalaropus tricolor, Western Sandpiper Calidris mauri and Least Sandpiper Calidris minutilla demonstrated that all three use surface tension transport of prey when feeding in water. I examined interspecific variation in the performance of this feeding mechanism with a high‐speed video system and a customized motion analysis system. Exploratory analyses indicated significant interspecific variation in distance the prey is transported per cycle of mandibular spreading, gape increase per unit transport, speed of transport, total number of cycles necessary to complete transport and total time to complete transport. The calidrid sandpipers also occasionally used other feeding mechanisms in conjunction with surface tension transport of prey. The discovery that these sandpipers, which normally obtain prey by probing, are capable of surface tension transport of prey implies that the capacity to employ this feeding mechanism may be widespread in the Scolopacidae and may have been a significant factor in the evolutionary radiation of phalaropes into aquatic environments.

Detection of the impact of predation by migratory shorebirds:an experimental test in the Fraser River estuary, British Columbia (Canada)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 144:23-40 (1996) - doi:10.3354/meps144023 Detection of the impact of predation by migratory shorebirds: an experimental test in the Fraser River estuary, British Columbia (Canada) Sewell MA Exclosure experiments are commonly used in marine soft sediments to examine changes in invertebrate density caused by shorebird predation. However, many of these exclosure experiments do not incorporate the spatial variability of the invertebrate prey in their design and/or analysis. This paper uses a short-term exclosure experiment and random sampling (Before/After predation) to assess reductions in invertebrate densities by western sandpiper Calidrismauri on the Fraser River estuary, British Columbia, Canada. During the spring >1 million western sandpiper stop over at the Fraser River estuary on their northward migration to breeding grounds in Alaska. Exclosure experiments and Before/After sampling were conducted at 3 sites on the Fraser River estuary that differed in their sediment characteristics and in their use for feeding by western sandpiper. An examination of cage effects showed that there were no alterations to sediment composition caused by the exclosure cage. However, there were changes in invertebrate numbers in the exclosure cage irrespective of shorebird predation. In particular, mobile invertebrates, such as gastropods and crustaceans, migrated into or out of the exclosure cages during the experiment. Overall, there was little evidence for reduction in invertebrate numbers caused by western sandpiper predation. In the exclosure experiment a significant decline was observed in the phyllodocid polychaete Eteone spp., but at a site with little evidence of shorebird predation. Before/After sampling showed some declines in invertebrate numbers, but this could reflect patchiness in invertebrate distributions rather than the direct action of predation. The use of statistical designs for detecting environmental impacts (e.g. BACI) is suggested for future studies of shorebird predation as they allow for the spatial and temporal variability of the invertebrate prey to be considered concomitant with the impact of the shorebird predator. General problems of sampling with sediment cores, high sample variance, and the reduced power of experimental tests need to be considered in future research on the interactions of shorebird predators and their marine invertebrate prey. Shorebird predation · Western sandpiper · Calidrismauri · Soft sediments · Exclosure experiment Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 144. Publication date: December 05, 1996 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1996 Inter-Research.