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Since the 1970s, many populations of shorebirds, including those breeding in the Arctic region, have been declining. One factor that may contribute to some of these declines is exposure to contaminants throughout the annual cycle. Here, we compared contaminant exposure (organochlorines, toxic trace elements) of four Arctic-breeding shorebirds (semipalmated plover Charadrius semipalmatus, semipalmated sandpiper Calidris pusilla, lesser yellowlegs Tringa flavipes, and short-billed dowitcher Limnodromus griseus), collected during breeding, migration, and wintering to examine how and when contaminants might pose a threat to these species. In general, plovers and dowitchers had higher levels of most organochlorine pesticides, and renal cadmium (Cd) and selenium (Se) than the other species. Although we found seasonal differences, no clear patterns in contaminant concentrations among sampling locations were detected but the concentrations found at the breeding grounds were always the highest for chlorinated pesticides and mercury (Hg). Our results suggest that birds migrating south are slowly depurating contaminant burdens, and that spring-migrating birds were exposed to primarily North American rather than Latin American contaminant sources at the time of sampling. We present these data collected in the 1990s to better interpret current-day trends, and potential contaminant exposure impacts on shorebird populations.

Understanding spatial connectivity of long-distance migrants is important for effective management and conservation of both game and nongame species. Hunting of Nearctic-breeding shorebirds occurs in the Caribbean and northern South America; however, the origins of harvested individuals are generally unknown. We used stable hydrogen isotopes (δ2H) in feathers of juvenile shorebirds to infer the origins of birds harvested at 2 sites in Barbados using probabilistic assignments based on a terrestrial–freshwater δ2H isoscape. We used tissue δ13C and δ15N values to filter individuals that had derived nutrients from marine sources. Natal origins of juvenile American Golden-Plover (Pluvialis dominica), Stilt Sandpiper (Calidris himantopus), Short-billed Dowitcher (Limnodromus griseus), and Lesser Yellowlegs (Tringa flavipes) were predicted to be mainly from the eastern parts of their breeding ranges in eastern Canada, with American Golden-Plover, Stilt Sandpiper, and Short-billed Dowitcher also having h...

Animal groups have emergent properties that result from simple interactions among individuals. However, we know little about why animals adopt different interaction rules because of sparse sampling among species. Here, we identify an interaction rule that holds across single and mixed-species flocks of four migratory shorebird species spanning a seven-fold range of body masses. The rule, aligning with a one-wingspan lateral distance to nearest neighbors in the same horizontal plane, scales linearly with wingspan but is independent of nearest neighbor distance and neighbor species. This rule propagates outward to create a global flock structure that we term the compound-V formation. We propose that this formation represents an intermediary between the cluster flocks of starlings and the simple-V formations of geese and other large migratory birds. We explore multiple hypotheses regarding the benefit of this flock structure and how it differs from structures observed in other flocking species., eLife digest Birds often fly in flocks ranging from very structured V-formations to unstructured clusters. Many studies have tried to prove what causes birds to flock and how it benefits them. Flocks, for example, may help birds to avoid predators and to navigate. Flying in a V-shaped formation likely also gives aerodynamic benefits that can make it easier to fly long distances. Few studies, however, have measured how the positions of birds in a flock relate to things like flying speed or the frequency of wing flaps. This is because it was difficult to take such measurements in large flocks of moving birds. Advances in cameras and computers are now making it easier to track individual birds flying in large flocks. The technology allows scientists to measure how birds position themselves in relation to other birds, or how flock-positioning varies by bird size, species, ecology, and behaviors. Such measurements may help scientists better understand why and how birds flock. Corcoran and Hedrick now show that four different types of shorebirds position themselves in the same way when flying in a flock. In the experiments, digital cameras recorded video of 18 cluster-like flocks of four different species of birds flying over a bird sanctuary or agricultural fields. The flocks ranged in size from a hundred to a thousand birds. Some flocks had two types of bird. The four types of birds – dunlin, short-billed dowitcher, American avocet, and marbled godwit – live in similar environments but greatly vary in size and fly at different speeds. Corcoran and Hedrick measured individual bird positions using three-dimensional computer reconstructions of the flocks. Each bird – regardless of size or species – most commonly flew about one wingspan to the side and between a half to one-and-a-half wingspans back from the bird in front of it. Birds flying in simple V-shaped formations follow similar rules. This suggests that birds flying in clusters may also gain aerodynamic benefits.

The Tofino Wah-nah-jus Hilth-hoo-is Mudflats on Vancouver Island, British Columbia, Canada, include both pristine areas and sites with residential and resort development. Shorebird counts were conducted at six sites around these mudflats in 2011 and compared with historical counts from 1988, 1989, and 1995. Temporal trends of counts did not vary among sites with different levels of disturbance. Over the entire mudflats, counts of Dunlin (Calidris alpina) moving northward had a negative trend over time (βyr = -0.04), as did counts of Western Sandpiper (Calidris mauri; βyr = -0.04), Least Sandpiper (Calidris minutilla; βyr = -0.03) and Short-billed Dowitcher (Limnodromus griseus; βyr = -0.04) moving southward. In contrast, counts of Black-bellied Plover (Pluvialis squatarola; βyr = 0.03) and Semipalmated Plover (Charadrius semipalmatus; βyr = 0.02) moving northward increased over time. Counts of Dunlin and Short-billed Dowitcher were lower at disturbed sites relative to non-disturbed sites, indica...

Field studies were carried out at two stations of the Ornithological Unit, Institute of Biological Problems of the North, Far East Branch, Russian Academy of Sciences, located in Nizhnekolymsk District, Yakutia, from May 15–20 in 1984, 1985, 1987, 1988, and 1990; on the northern coast of Pukhovoy Bay, the southern island of Novaya Zemlya, from June 1st in 1994; at Cape Beliy Nos, the Yugorsky Peninsula, from June 1st in 1995–1997. Classic associations are detected in interspecies flocks of sandpipers between the following species: the Pacific golden plover and the curlew sandpiper, the pectoral sandpiper and the long-billed dowitcher, the pectoral sandpiper and the dunlin, and the grey plover and the dunlin. However, the total amount of birds forming associations is not large. In species of group “A” (the grey plover, the Pacific golden plover, and the pectoral sandpiper), no difference has been observed in migratory birds’ behavior within interspecies or conspecific flocks. Species of group “B” (the dunlin, the curlew sandpiper, and the long-billed dowitcher), on the contrary, change their behavior sharply depending on whether they belong to an association or not. Species of group “A” do not get any advantages when forming an association. Unlike them, species of group “B” profit from associating: the time spent on foraging substantially increases; more time is spent on rest, and less time is spent on reconnaissance and vigilance (readiness for actions); the safety of the birds is enhanced. On the other hand, in species of group “B” there are also disadvantages related with associating: i.e., interspecies competition for food; foraging in suboptimal habitats which may in turn lead to a notable increase in the time spent by birds on foraging. It is proposed that the advantages and limitations of associating for the species of group “B” cancel each other out to a certain extent, and this explains rather small number of birds forming associations.

It is well established that once birds have laid their eggs they sometimes incubate non-egg objects. However, reports of birds incubating solely non-egg objects (without prior manipulation by researchers) are rare. Here we report on our observation of a Long-billed Dowitcher Limnodromus scolopaceus incubating a clutch composed entirely of mammalian bones. To our knowledge, this is the first report on (a) incubation of foreign objects in Scolopacidae, (b) incubation of a ‘clutch’ composed entirely of bones, and (c) incubation of foreign objects in a nest atypical for this species in both construction and nest habitat. We discuss possible explanations for this presumably maladaptive behaviour.

Incorporating lightweight synthetic lines, nylon fish netting and sailboat and fishing hardware, the drop net is an effective, portable method to trap many different species of shorebirds. During 2006 and 2007 drop nets were used to safely capture more than 265 targeted shorebirds in habitats in North and South America. Shorebirds captured included Calidris sandpipers, Charadrius sandpipers, Buff-breasted Sandpiper (Tringites subruficollis), and dowitchers (Limnodromus).

We surveyed the shoreline of a large terminal lake in southern Saskatchewan (Old Wives Lake) for sick or dead birds and estimated shorebird numbers during avian botulism outbreaks. Nearly double the number of shorebirds were present in 1999 compared with 1998. The most commonly observed shorebirds in both years were the Short-billed Dowitcher (Limnodromus griseus) and Long-billed Dowitcher (L. scolopaceus). Water levels were monitored, revealing a greater drawdown effect in 1998. Small species (e.g. Least Sandpiper (Calidris minutilla), Semipalmated Sandpiper (C. pusilla), and Sanderling (C. alba)) were much more common in 1998. Much of the data that exist on shorebird mortality during botulism kills is in the form of unpublished annual agency clean-up reports. These reports suggest that the American Avocet (Recurvirostra americana), yellowlegs (Tringa melanoleuca and T. flavipes), and the small Calidris sandpipers are the most commonly affected species. We suggest some biases inherent in these c...

Field experiments have shown that predators can either increase or decrease the patchiness of prey populations inhabiting hard substrates. In theory, removal that is correlated with initial density (thinning) reduces spatial variance; removal that is correlated with itself (clearing) increases spatial variance. Simulations showed that the relative importance of thinning and clearing depends on the pattern of removal and on the number of unoccupied sites. The observed change in spatial variance of the tubiculous polychaete (Clymenella torquata) matched the change calculated from the foraging dispersion of an avian predator, the short-billed dowitcher (Limnodromus griseus), at the spatial scale of 0.2-3 km2 flats but not at the scale of 1-ha plots within flats.

Enterprise networks are increasingly offloading the responsibility for worm detection and containment to the carrier networks. However, current approaches to the zero-day worm detection problem such as those based on content similarity of packet payloads are not scalable to the carrier link speeds (OC-48 and up-wards). In this paper, we introduce a new system, namely DoWitcher, which in contrast to previous approaches is scalable as well as able to detect the stealthiest worms that employ low-propagation rates or polymorphisms to evade detection. DoWitcher uses an incremental approach toward worm detection: First, it examines the layer-4 traffic features to discern the presence of a worm anomaly; Next, it determines a flow-filter mask that can be applied to isolate the suspect worm flows and; Finally, it enables full-packet capture of only those flows that match the mask, which are then processed by a longest common subsequence algorithm to extract the worm content signature. Via a proof-of-concept implementation on a commercially available network analyzer processing raw packets from an OC-48 link, we demonstrate the capability of DoWitcher to detect low-rate worms and extract signatures for even the polymorphic worms.

During a study of the endohelminths of wading birds from the Texas Gulf coast, 5 specimens of an undescribed species of Haematotrephus (Cyclocoelidae) were studied and described. These specimens were collected by Dr. J. Teague Self, former professor, Department of Zoology, University of Oklahoma, Norman, Oklahoma from the air sacs of a long-billed dowitcher, Limnodromus scolopaceus, that was collected from the Cheyenne Bottoms, Roger Mills County, Oklahoma on August 3, 1963 and deposited in the Manter Laboratory of Parasitology. Haematotrephus limnodromi n. sp. can be distinguished from all the other species in the genus that lack an oral sucker (H. capellae, H. chengi, H. dollfusi, H. fasciatum, H. kossacki, H. lanceolatum, H. longisacculatum, H. nebularium, H. nigropunctatum, and H. phaneropsolus) by having intertesticular uterine loops. Corpopyrum brazilianum (originally described as Cyclocoelum brazilianum) is transferred as the second species in Selfcoelum, Corpopyrum dendrei is transferred to Neohaematotrephus, and Haematotrephus facioi is transferred to Wardianum. This is the first report of a species of Haematotrephus from a species of Limnodromus.

The complex aerial song of the Short-billed Dowitcher (Limnodromus griseus) is described, and recordings from northern British Columbia (subspecies caurinus), northern Manitoba (hendersoni), and Labrador (griseus) are analyzed. The song is a stereotyped sequence of one to five units that are repeated rapidly and increase successively in duration. Each song unit consists of three readily distinguished element types (I, II, III), which form graded series occurring in fixed sequence. Song structure and element types are similar in all subspecies, but significant quantitative differences exist; the central subspecies (hendersoni) is clearly distinguished from the other two, in particular. These geographic differences are slight in comparison with primary song in many species of Oscines.

The dynamics of the organization of a community of six species of migrant predatory shorebirds (Least Sandpiper, Semipalmated Sandpiper, Dunlin, Short—billed Dowitcher, Lesser Yellowlegs, and Semipalmated Plover) was appraised by studying foraging behavior and habitat utilization under winter conditions in southern Florida and under summer conditions in the eastern Canadian Arctic. Eight foraging methods, defined primarily on the basis of how the bill is used and the pattern of locomotion, constitute the behavioral repertoire of the species. Each foraging method is correlated with a particular rate of locomotion (distance/time) and rate of feeding (pecking or probing/time). Feeding and locomotion rates seem independent of air temperature, number of conspecifics, and total number of shorebirds foraging nearby. Instead, the seasonal changes in these rates are probably related to food density. On the basis of these findings and of differences in rates of feeding and locomotion between species the most reason...

The Asiatic Dowitcher (Limnodromus semipalmatus) which breeds in Siberia is a rare species of Scolopacidae and has never been recorded in Japan. The author has, however, found one Asiatic Dowitcher on May 23rd., 1972 at the Lake Ogawara in Aomori Pref. and has been able to take photographs in color.The details from this observation and the field identification comparing with the three species which might easily be confused, i. e. L. scolopaceus, Limosa limosa and L. lapponica, are given in this report.

THE status of the dowitchers occurring across the length and breadth of the North American continent has been a matter of dispute practically since the time that the long-billed bird, Limnodromus scolopaceuw, was first described by Say in 1823 under the name of Limosa scolopacea. Various authors have endeavored from time to time to settle the matter by special investigation. In spite of these attempts, current literature is still full of doubts as to whether there is only one very variable dowitcher, whether there are two subspecies or whether there are actually two full species. It is the purpose of this paper to re-examine the entire question in light of the recent discovery of two fresh breeding grounds, from both of which skins are available, in Alberta and Manitoba: to describe and name a new subspecies (hendersoni): and to substantiate the validity of both the previously recognized forms, griseus and scolopaceus. The importance of breeding skins to an investigation of this sort requires no emphasis. Three breeding areas are now certainly known. The first to be discovered, within the Arctic Circle, from the Anderson River westward, has been recognized since MacFarlane (MacFarlane, 1908; Poynting, 1895-6) first collected birds and eggs in 1864. Since then various collectors have obtained eggs, downy young and adult skins from this general region. Without exception, as far as I am aware, these have all been identified as scolopaceus by the collectors themselves and by others who have examined them. Some of these skins are included in the present investigation. The second breeding area was finally established in 1925 when, on

Habitat selection by six species of shorebirds (Least Sandpiper, Semipalmated Sandpiper, Dunlin, Short-billed Dowitcher, Lesser Yellowlegs, and Semipalmated Plover) was studied on wintering and breeding ranges. Features of the terrain that characterize the feeding microhabitat were compared to the surrounding habitat and examined in relation to culmen and tarsal length. The main results were, (a) The shorebirds tend to forage along edges adjacent to taller vegetation and deeper water than are typical of the feeding habitat; (b) The diversity of the feeding microhabitat is greater in summer than in winter; (c) Culmen length is positively correlated with vegetation height and diversity of the feeding microhabitat; (d) Tarsal length is positively correlated with water depth in the feeding microhabitat; and (e) The degree to which the utilized microenvironment is distinct from the surrounding area varies among the species. The bill of a shorebird is a versatile instrument and this is not obvious from morphology alone. An increase in bill length appears to produce an increase in versatility and exploitation of a more diverse environment.