Charadrius Semipalmatus Research Articles

Contrasting migratory journeys and changes in hippocampal astrocyte morphology in shorebirds.

Semipalmated sandpiper (Calidris pusilla) migration to the Southern Hemisphere includes a 5-day non-stop flight over the Atlantic Ocean, whereas semipalmated plover (Charadrius semipalmatus) migration, to the same area, is largely over land, with stopovers for feeding and rest. We compared the number and 3D morphology of hippocampal astrocytes of Ch.semipalmatus before and after autumnal migration with those of C.pusilla to test the hypothesis that the contrasting migratory flights of these species could differentially shape hippocampal astrocyte number and morphology. We captured individuals from both species in the Bay of Fundy (Canada) and in the coastal region of Bragança (Brazil) and processed their brains for selective GFAP immunolabeling of astrocytes. Hierarchical cluster analysis of astrocyte morphological features distinguished two families of morphological phenotypes, named type I and type II, which were differentially affected after migratory flights. Stereological counts of hippocampal astrocytes demonstrated that the number of astrocytes decreased significantly in C.pusilla, but did not change in Ch.semipalmatus. In addition, C.pusilla and Ch.semipalmatus hippocampal astrocyte morphological features were differentially affected after autumnal migration. We evaluated whether astrocyte morphometric variables were influenced by phylogenetic differences between C.pusilla and Ch.semipalmatus, using phylogenetically independent contrast approach, and phylogenetic trees generated by nuclear and mitochondrial markers. Our findings suggest that phylogenetic differences do not explain the results and that contrasting long-distance migratory flights shape plasticity of type I and type II astrocytes in different ways, which may imply distinct physiological roles for these cells.

The influence of migration patterns on exposure to contaminants in Nearctic shorebirds: a historical study.

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.

Keeping safe and fed: large heterospecific shorebird flocks to decrease intraspecific competition

Shorebirds join cohesive flocks for safety. The joining of individuals of several species in large heterospecific flocks can optimise individual vigilance and foraging. However, a large number of conspecific individuals in flocks may deplete food resources and increase intraspecific competition. In the present study, we argue that Nearctic–Neotropical migratory shorebird species join large heterospecific flocks in a balanced number as a way of controlling intraspecific competition. We recorded monospecific and heterospecific flocks in urban beaches from southeastern Brazil and annotated the species richness and the number of individuals per bird species per flock. Besides, we recorded the number of people around shorebird flocks to examine any relationship with flock size. We also recorded the foraging rate of the semipalmated plover Charadrius semipalmatus, a common migrant species in the region, as a species model to test competition and vigilance. We hypothesised that this species would exhibit a low foraging rate in scenarios with high intraspecific competition (i.e. large flocks with a high number of conspecifics) and high density of people, which may disturb birds. In the initial results, the density of people did not influence size of monospecific and heterospecific flocks; heterospecific flocks were larger than monospecific flocks, and heterospecific flocks increased in size by the addition of more species rather than more individuals of the same species. These data reflect a decrease in the relative abundance of individuals per species. Additionally, the semipalmated plover foraging rate was reduced in monospecific flocks, flocks with a high relative abundance (and total number) of the specific individuals and flocks surrounded by a high density of people. All these results indicate that shorebirds may adjust flock composition and size according to preferred foraging conditions, i.e. large and balanced heterospecific flocks with less intraspecific competition and less vigilance to potential predators in wintering areas.

Differential Change in Hippocampal Radial Astrocytes and Neurogenesis in Shorebirds With Contrasting Migratory Routes.

Little is known about environmental influences on radial glia-like (RGL) α cells (radial astrocytes) and their relation to neurogenesis. Because radial glia is involved in adult neurogenesis and astrogenesis, we investigated this association in two migratory shorebird species that complete their autumnal migration using contrasting strategies. Before their flights to South America, the birds stop over at the Bay of Fundy in Canada. From there, the semipalmated sandpiper (Calidris pusilla) crosses the Atlantic Ocean in a non-stop 5-day flight, whereas the semipalmated plover (Charadrius semipalmatus) flies primarily overland with stopovers for rest and feeding. From the hierarchical cluster analysis of multimodal morphometric features, followed by the discriminant analysis, the radial astrocytes were classified into two main morphotypes, Type I and Type II. After migration, we detected differential changes in the morphology of these cells that were more intense in Type I than in Type II in both species. We also compared the number of doublecortin (DCX)-immunolabeled neurons with morphometric features of radial glial–like α cells in the hippocampal V region between C. pusilla and C. semipalmatus before and after autumn migration. Compared to migrating birds, the convex hull surface area of radial astrocytes increased significantly in wintering individuals in both C. semipalmatus and C. pusilla. Although to a different extent we found a strong correlation between the increase in the convex hull surface area and the increase in the total number of DCX immunostained neurons in both species. Despite phylogenetic differences, it is of interest to note that the increased morphological complexity of radial astrocytes in C. semipalmatus coincides with the fact that during the migratory process over the continent, the visuospatial environment changes more intensely than that associated with migration over Atlantic. The migratory flight of the semipalmated plover, with stopovers for feeding and rest, vs. the non-stop flight of the semipalmated sandpiper may differentially affect radial astrocyte morphology and neurogenesis.

Migration Distance and Body Condition Influence Shorebird Migration Strategies and Stopover Decisions During Southbound Migration

Technological constraints have limited our ability to compare and determine the proximate and ultimate drivers of migratory behaviour in small-bodied birds. Small VHF transmitters ( 9,000 km; pectoral sandpiper, Calidris melanotos, and white-rumped sandpiper, Calidris fuscicollis) would be more likely to migrate with characteristics of a time-minimizing migration strategy compared to species migrating intermediate distances (5,000-7,500 km; semipalmated sandpiper, Calidris pusilla; and lesser yellowlegs, Tringa flavipes) or shorter distances (~5,000 km; least sandpiper, Calidris minutilla; semipalmated plover, Charadrius semipalmatus), which would migrate with more characteristics of an energy-minimizing strategy. Our results indicate that migration and stopover behaviours for adults matched this prediction; longer distance migrants had longer stopover lengths, departed with higher relative fuel loads, flew with faster ground and airspeeds, and had a lower probability of stopover in North America after departing the subarctic. The predicted relationship between migration distance and migratory strategy was not as clear for juveniles. Despite our prediction that longer distance migrants would be less wind selective at departure and fly into headwinds en route, all species and age classes departed and migrated with supportive winds. Birds with higher estimated fuel loads at departure were less likely to stop in North America after departing the subarctic, indicating that some birds attempted non-stop flights from the subarctic to the Caribbean or South America. Additionally, within species, adults with higher relative fuel loads at departure had a higher detection probability after departing the subarctic, which we interpret as evidence of higher survival compared to juveniles. This study shows that migratory behaviour of shorebirds has predictable patterns based on migration distance that are moderated by body condition of individuals, with potential implications for fitness.

Use of stabilized thaw slumps by Arctic birds and mammals: evidence from Herschel Island, Yukon

As evidenced by animal sign (scat, active nests, nesting materials, rodent runways) observed across five stabilized retrogressive thaw slumps and two areas of undisturbed upland tundra, Arctic birds and mammals on Herschel Island, Canada, use stabilized thaw slumps differently than undisturbed tundra. Rodent winter nests and scat were found exclusively in undisturbed tundra and at a 250-year-old stabilized thaw slump site, whereas rodent runways and Semipalmated Plover (Charadrius semipalmatus) nests were found exclusively at 10- and 20-year-old stabilized thaw slump sites. Bird scat was found in each tundra type, but was most common in the youngest sites, and the number of observations decreased with increasing site age. Caribou (Rangifer tarandus granti) scat was found at all sites, whereas Muskox (Ovibos moschatus) scat was not found at 20-year-old sites and was most common in undisturbed tundra. To our knowledge, these observations are the first examples of birds and mammals using stabilized thaw slump habitat of different ages, and they provide new avenues of research for Arctic wildlife biologists concerned with the adaptation of these animals to permafrost disturbance and the resulting changes in vegetation cover.

Nuevos registros de aves acuáticas para el interior del Estado de Jalisco: caso Laguna de Sayula, México

El conocimiento de la avifauna en México, es el resultado de muchos años de exploraciones en áreas específicas, sin embargo a pesar del esfuerzo realizado, en algunas regiones de México aún se desconoce su composición y distribución; tal es el caso de los humedales continentales, los cuales representan sitios de invernada y de paso migratorio para una gran variedad de aves acuáticas y terrestres del Neártico, así como sitios de reproducción para especies residentes. Se destacan observaciones realizadas en el Sitio Ramsar Laguna de Sayula, resultado de un estudio avifaunístico a largo plazo con muestreos mensuales durante cinco periodos de migración. Se reportan seis nuevos registros para el humedal y algunos para el interior del estado (Dendrocygna autumnalis, Branta canadensis, Sula leucogaster, Pelecanus occidentalis, Pluvialis squatarola y Charadrius semipalmatus) y se informa la presencia de Anser albifrons y Anser rossii con pocos registros publicados para la zona.

No effects of asynchrony between hatching and peak food availability on chick growth in Semipalmated Plovers (Charadrius semipalmatus) near Churchill, Manitoba

Birds rely on consistent patterns of food availability on their breeding grounds to successfully complete their breeding cycle. Due to ongoing warming of the sub-Arctic, there is potential for a mismatch between the peak in available invertebrate biomass and the peak in food demand for shorebird chicks. During the summers of 2010 and 2011, we investigated the relationship between temperature and benthic and terrestrial invertebrate biomass, measured using three sampling techniques in Churchill, Manitoba. We also investigated the relationship between timing of breeding of Semipalmated Plovers (Charadrius semipalmatus) and timing of peaks in invertebrate biomass. In 2011, chick growth rates were also measured to examine whether hatching in synchrony with the peak in invertebrate biomass during the brood rearing period affected growth rates. In 2010, emergent and core invertebrate biomass were negatively related to soil degree days, whereas in 2011, core biomass increased with soil degree days and pitfall biomass increased with air temperature. Total invertebrate biomass (summed over trap types) peaked from 25 to 31 days before the median chick hatch date in 2010 and 10 days after the median chick hatch date in 2011. In 2011 we did not detect any effects of asynchrony on the growth of Semipalmated Plover chicks. These results may indicate that food resources in their environment remain adequate throughout the breeding season, despite inter-annual fluctuations in the timing of invertebrate peaks.

Mixed effects of an introduced ecosystem engineer on the foraging behavior and habitat selection of predators.

Invasive ecosystem engineers both positively and negatively affect their recipient ecosystems by generating novel habitats. Many studies have focused on alterations to ecosystem properties and to native species diversity and abundance caused by invasive engineers. However, relatively few studies have documented the extent to which behaviors of native species are affected. The red seaweed Gracilaria vermiculophylla (Rhodophyta) invaded estuaries of the southeastern United States within the last few decades and now provides abundant aboveground vegetative cover on intertidal mudflats that were historically devoid of seaweeds. We hypothesized that G.vermiculophylla would affect the foraging behavior of native shorebirds positively for birds that target seaweed-associated invertebrates or negatively for birds that target prey on or within the sediment now covered with seaweed. Visual surveys of mudflats >1ha in size revealed that more shorebirds occurred on mudflats with G.vermiculophylla relative to mudflats without G.vermiculophylla. This increased density was consistent across 7 of 8 species, with the one exception being the semipalmated plover Charadrius semipalmatus. A regression-based analysis indicated that while algal presence predicted shorebird density, densities of some bird species depended on sediment composition and infaunal invertebrate densities. At smaller spatial scales (200m2 and <1m2 ), experimental removals and additions of G.vermiculophylla and focal observations showed strong variation in behavioral response to G.vermiculophylla among bird species. Birds preferentially foraged in bare mud (e.g., C.semipalmatus), in G.vermiculophylla (e.g., Arenaria interpres), or displayed no preference for either habitat (e.g., Tringa semipalmata). Thus, while the presence of the invasive ecosystem engineer on a mudflat appeared to attract greater numbers of these predators, shorebird species differed in their behavioral responses at the smaller spatial scales that affect their foraging. Our research illuminates the need to account for species identity, individual behavior, and scale when predicting the impacts of invasive species on native communities.

Investigation of Enteric Viruses in the Feces of Neotropical Migratory Birds Captured on the Coast of the State of Pará, Brazil

ABSTRACT Migratory birds can become long-distance vectors for a wide range of microorganisms and can cause human disease, being the Brazilian coast a gateway for northern migratory birds. These animals are considered natural reservoirs of different viruses that cause important diseases, being relevant research of viral pathogens in migratory birds to epidemiology surveillance. The objective of the study was to investigate the presence of avian rotavirus (AvRV), avian reovirus (ARV) and picobirnavirus (PBV) in Neotropical migratory birds captured on the coast of Brazil. A total of 23 individual fecal samples of the migratory birds species Calidris pusilla (20 birds), Numenius phaeopus (1 bird) and Charadrius semipalmatus (2 birds) were collected. Fecal suspensions were prepared from the collected samples for subsequent extraction of double-stranded RNA (dsRNA), which was subjected to polyacrylamide gel electrophoresis (PAGE) and reverse transcription polymerase chain reaction (RT-PCR). The electrophoretic profiles were not detected by PAGE, and the amplification for the studied viruses PBV, ARV and AvRV (specie D, gene VP6 and NSP4) were negative. Positivity for AvRVD, VP7 gene was of 4.35% (1/23) for the migratory bird Calidris pusilla. After sequencing and building the tree of phylogenetic relationships avian Rotavirus Group D identified in this study was phylogenetically related and grouped into one branch, together to previously reported AvRVD from Brazil in chicken flocks with 99.8% nucleotide and 100% amino acid similarities.

Temporal variation in the mass and plumage of four Charadriiformes species on the north-eastern coast of Brazil

Each year, thousands of Nearctic shorebirds migrate from breeding grounds in the northern hemisphere to wintering grounds in South America. At the wintering sites, in addition to moulting their flight feathers and plumage, shorebirds engage in feeding to increase body mass to gain sufficient energy for the return migration to the breeding grounds. This study aims to describe the temporal variation of body mass and plumage of the Semipalmated Plover (Charadrius semipalmatus), Spotted Sandpiper (Actitis macularius), Sanderling (Calidris alba) and Semipalmated Sandpiper (Calidris pusilla) during the wintering season on the north-eastern coast of Brazil and to evaluate the relationship between mass gain and plumage moulting. The lowest average masses for each of these species were recorded in October, November, December and January, usually when displaying non-breeding plumage. Shorebirds with intermediate and breeding plumage were frequently recorded in the migration preparation period beginning in April, with a significant increase in body mass. However, for some individuals low masses were recorded late during the wintering period and these were all found to be actively moulting. The highest values for body mass were recorded for shorebirds with breeding and intermediate plumage that were not actively moulting, nearing the end of wintering period.

Diet and prey size selectivity of Semipalmated Plovers (Charadrius semipalmatus) in coastal Georgia

We examined diet of nonbreeding Semipalmated Plovers (Charadrius semipalmatus Bonaparte, 1825) in the Cumberland Island estuary, Georgia, USA, through fecal sample analysis. We also examined prey size selectivity by Semipalmated Plovers for the most common prey item found in the fecal samples, which are polychaetes in the family Nereidae (= Nereididae). We compared the size distribution of polychaetes in Semipalmated Plover fecal samples from salt marshes and mudflats with the size distribution of polychaetes sampled from the two habitats. Semipalmated Plovers foraging on mudflats had less variable diets than those foraging on salt marshes, although the mean number of prey per Semipalmated Plover fecal sample was similar between the two habitats. Size selectivity by Semipalmated Plovers of nereid (= nereidid) polychaetes varied as a function of habitat, with Semipalmated Plovers eating larger polychaetes in salt marshes than in mudflats, although in both habitats Semipalmated Plovers avoided extremely small and (or) large ones. Semipalmated Plovers took fewer of the available prey groups and were more selective in sizes of the dominant prey group on mudflats, where prey densities were the highest. These observations are consistent with predictions from optimal foraging theory.

Monitoring Migrating Shorebirds at the Tofino Mudflats in British Columbia, Canada: is Disturbance a Concern?

Abstract. 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...

First records of Charadrius semipalmatus, Bonaparte 1825 (Charadriidae) and Gelochelidon nilotica Gmelin 1789 (Sternidae) in the State of Minas Gerais, Brazil.

Around forty bird species habitually reproduce in the Northern Hemisphere during summer, and migrate to the Southern Hemisphere during northern winter. These migrating birds fly together in large or small groups until they have reached the Caribbean, Central American, or Brazilian shores. Charadrius semipalmatus, Bonaparte 1825, is one of these migrating species that uses resting and feeding areas along eastern and western coasts of North and South America, with several records for the Brazilian coast, and very few for the inland country. On November 24, 2011, an individual of this species was observed on the banks of one of the lakes that compose a complex of about 40 temporary lakes within the Karst of Lagoa Santa Environmental Protection Area. On October 29 and 30, 2012 a single individual of Gelochelidon nilotica, Gmelin 1789, was also observed in Sumidouro State Park. We suggest that these specimens have used the Atlantic Ocean migration route, following the São Francisco River Basin, until the karst area. Although highly impacted, the temporary lakes within the Karst of Lagoa Santa still harbor a significant number of bird species, and serve as resting and feeding places for migratory or errant species that are still eliciting new records.

First records of chewing lice (Phthiraptera: Menoponidae) in Pacific migratory shorebirds wintering in Ecuador.

Chewing lice were collected from small shorebirds (Charadriformes: Scolopacidae) overwintering in foraging grounds of coastal Ecuador. On 27 occasions at least one louse (3.7%) was collected from six host species. Based on external morphological characters, at least two species of chewing lice could be preliminary identified (family: Menoponidae), including Actornithophilus umbrinus (Burmeister, 1842) and Austromenopon sp. A. umbrinus was found in the Western Sandpiper (Calidris mauri), Least Sandpiper (C. minutilla), Stilt Sandpiper (C. himantopus), Semipalmated Plover (Charadrius semipalmatus) and Wilson's phalarope (Phalaropus tricolor), while Austromenopon sp. is presumably the first record collected from the Surfbird (Aphriza virgata). These findings indicate that the distribution of these chewing lice species covers at least the regions around the equator (latitude 0°) until the Arctic in the north, but probably also includes the entire winter distribution area of the host species. This is the first study of chewing lice from Ecuador's mainland coast and more research is required to understand the host-parasite ecology and ectoparasitic infection in shorebirds stopping over the region.

千葉県九十九里浜におけるミズカキチドリ&lt;i&gt;Charadrius semipalmatus&lt;/i&gt;の観察記録

千葉県九十九里浜におけるミズカキチドリ&lt;i&gt;Charadrius semipalmatus&lt;/i&gt;の観察記録

Staging ecology of Semipalmated Plover (Charadrius semipalmatus) and Semipalmated Sandpiper (Calidris pusilla) juveniles in the St. Lawrence River Estuary during fall migration

The acquisition of body reserves by migrating shorebirds at specific staging sites is critical for reaching their breeding or wintering grounds. As many North American shorebird populations are declining, major staging sites need to be identified for effective conservation plans. Changes in body mass of Semipalmated Plover (Charadrius semipalmatus Bonaparte, 1825) and Semipalmated Sandpiper (Calidris pusilla (L., 1766)) juveniles, as well as length of stay and daily movements by Semipalmated Plover juveniles during fall migration, were studied in the St. Lawrence River Estuary in southern Quebec, Canada. Most juveniles of both species captured early in the migration period weighed less than the estimated mean fat-free mass. Body mass increased steadily in juveniles of both species during staging. Mean body masses of birds captured in our study area were similar to or higher than those of juveniles of both species captured along the North Atlantic coast. Length of stay of radio-tracked Semipalmated Plover juveniles ranged from 2 to 28 days. Body mass at capture and length of stay were negatively associated, suggesting that individuals refuelled before resuming their migration. Overall, these results provide evidence that the St. Lawrence River Estuary is an important staging site for Semipalmated Plover and Semipalmated Sandpiper juveniles.

Mercury concentration in the eggs of four Canadian Arctic-breeding shorebirds not predicted based on their population statuses

Methylmercury is a toxic form of mercury which persists in food webs for long periods of time and biomagnifies up successive trophic levels. Shorebirds breeding in the Arctic are exposed to methylmercury, derived from both natural and anthropogenic sources, when they ingest their invertebrate prey. Populations of many shorebird species are believed to be declining and one hypothesis for these declines is that they are due to detrimental effects of contaminants, including methylmercury. To test this hypothesis, we assessed mercury contamination in eggs of four Canadian Arctic-breeding shorebird species: black-bellied plover (Pluvialis squatarola), ruddy turnstone (Arenaria interpres), semipalmated plover (Charadrius semipalmatus) and white-rumped sandpiper (Calidris fuscicollis). Black-bellied plovers and ruddy turnstones are declining in the western hemisphere, whereas white-rumped sandpipers and semipalmated plovers have stable or slightly increasing populations. We found no relationship between egg mercury concentration and population trend for these four shorebird species. Intraspecific variation in mercury concentration was high. Notably, the mercury concentrations were much higher than levels found in a previous study of eggs of the same shorebird species from this same site, suggesting that mercury contamination may be subject to substantial inter-annual variation in the Canadian Arctic food web.

Flutuações mensais na abundância dos Charadriidae e Scolopacidae da praia da Ilha Comprida, São Paulo, Brasil

Foram registradas as freqüências de ocorrências e as flutuações mensais das famílias Charadriidae e Scolopacidae ao longo de um transecto de 70 km de praia entre o Boqueirão Sul e o Boqueirão Norte na Ilha Comprida, estado de São Paulo, durante o período de um ano (Janeiro a dezembro de 2010). Um total de 12.153 indivíduos de aves foram contados com a maior abundância ocorreu entre outubro e abril e a mais baixa entre maio a setembro. Das 20 espécies registradas as mais abundantes foram Charadrius semipalmatus, Charadrius colaris, Vanellus chilensis e Tringa flavipes. As menos abundantes foram Tryngites subruficolis, Limosa haemastica,Tringa melanoleuca e Actitis macularia. Dezesseis espécies eram migrantes do Hemisfério Norte, duas migrantes do Hemisfério Sul, e duas residentes. Sete espécies foram registradas regularmente, cinco esporadicamente e oito foram ocasionais. Quatro espécies neárticas foram registradas em Junho e julho, provavelmente indicando a presença de indivíduos imaturos não reprodutores. O número de espécies e o número de indivíduos provavelmente flutuaram devido a migração ou movimentos entre as praias vizinhas. A praia da Ilha Comprida é um importante sítio de parada durante a migração para muitas aves de praia na costa Sul do estado de São Paulo. Por esse motivo, devem ser feitos esforços de preservação, especialmente tendo em conta a crescente pressão de desenvolvimento que ameaça essa região.

Directional selection and repeatability in nest-site preferences of Semipalmated Plovers (Charadrius semipalmatus)

Using marked individuals, we assessed directional selection and repeatability of nest-site characteristics of Semipalmated Plovers (Charadrius semipalmatus Bonaparte, 1825) on Akimiski Island, Nunavut, Canada, 2002–2005, to test the hypothesis that long- and short-term selection patterns were in the same direction. Plovers placed nests in microsites (1 m2 scale) with more pebbles and less bare mud and vegetation than what was available in the environment, indicating long-term selection for these features. Linear (directional selection) effects were stronger than quadratic (stabilizing or disruptive) effects in 3 of 4 years and in the analysis of all data. In the combined 4-year sample, significant directional selection occurred in the opposite direction than that present when comparing used and available sites. Birds with more bare mud and vegetation and fewer pebbles at their nest sites were more successful than birds with pebbled nest sites. Repeatability of nest-site preferences was low and nonsignificant. Neither successful nor unsuccessful pairs chose significantly different nest-site characteristics in subsequent nesting attempts, but options for moving to different nest sites may be limited by interannual site fidelity. Wide individual variability and low repeatability of nest-site characteristics suggests behavioral flexibility in the population. Applying quantitative genetic techniques to patterns of habitat selection may allow researchers to predict the degree to which animals can adjust to changing environments.