| elemental profiles in feather samples from a mercury-contaminated lake in central california | flight feathers from six bird species at clear lake, ca were analyzed to determine the extent and distribution of mercury contamination from an abandoned mercury mine and associated levels of 14 other elements. feather samples were collected from adult and juvenile osprey (pandion haliaetus), including juvenile osprey from three additional comparison sites; adult western grebes (aechmophorus occidentalis); adult great blue herons (ardea herodias); adult mallards (anas platyrhynchos); adult turke ... | 1998 | 9601923 |
| short-term survival and effects of transmitter implantation into western grebes using a modified surgical procedure. | two pilot trials and one study in a closely related grebe species suggest that western grebes (aechmophorus occidentalis) will not tolerate intracoelomic transmitter implantation with percutaneous antennae and often die within days of surgery. wild western grebes (n = 21) were captured to evaluate a modified surgical technique. seven birds were surgically implanted with intracoelomic transmitters with percutaneous antennae by using the modified technique (transmitter group), 7 received the same ... | 2011 | 22950313 |
| organochlorine pesticide and pcb residues in western grebes from bear river migratory bird refuge, utah. | | 2001 | 114257 |
| estimating mercury exposure of piscivorous birds and sport fish using prey fish monitoring. | methylmercury is a global pollutant of aquatic ecosystems, and monitoring programs need tools to predict mercury exposure of wildlife. we developed equations to estimate methylmercury exposure of piscivorous birds and sport fish using mercury concentrations in prey fish. we collected original data on western grebes (aechmophorus occidentalis) and clark's grebes (aechmophorus clarkii) and summarized the published literature to generate predictive equations specific to grebes and a general equatio ... | 2015 | 26449260 |
| western and clark's grebes use novel strategies for running on water. | few vertebrates run on water. the largest animals to accomplish this feat are western and clark's grebes (aechmophorus occidentalis and aechmophorus clarkii). these birds use water running to secure a mate during a display called rushing. grebes weigh an order of magnitude more than the next largest water runners, basilisk lizards (basilicus basiliscus), and therefore face a greater challenge to support their body weight. how do these birds produce the hydrodynamic forces necessary to overcome g ... | 2015 | 25911734 |
| avioserpens in the western grebe (aechmophorus occidentalis): a new host and geographic record for a dracunculoid nematode and implications of migration and climate change. | we report a new host and geographic range for the dracunculoid nematode (avioserpens sp.) in a western grebe (aechmophorus occidentalis) from southern arizona, us. this discovery underscores the importance of parasite discovery and identification in the wildlife rehabilitation setting. climate change and weather events affect the migratory spread of unusual parasites. | 2016 | 26555111 |
| using latent selection difference to model persistence in a declining population. | population persistence is a direct measure of the viability of a population. monitoring the distribution of declining populations or subpopulations over time can yield estimates of persistence, which we show can be modeled as a latent selection difference (lsd) contrasting attributes of sites where populations have persisted versus those that have not. predicted persistence can be modeled with predictor covariates to identify factors correlated with species persistence. we demonstrate how to mod ... | 2014 | 24866172 |
| citizen science reveals an extensive shift in the winter distribution of migratory western grebes. | marine waterbirds have shown variable trends in abundance over the past four decades with some species displaying steep declines along the pacific coast from british columbia through california. one of the most dramatic changes has been that of western grebes (aechmophorus occidentalis) in the salish sea. this region was a former core of the species wintering distribution but they have become increasingly rare prompting calls for conservation action. a more thorough understanding of this situati ... | 2013 | 23840328 |
| effects of freshwater housing and fluid types on aquatic bird serum electrolyte concentrations. | recent seabird mass morbidity events have highlighted the need to elucidate the effects of freshwater and hypertonic saline use for fluid therapy and housing in captive aquatic birds. serum electrolyte concentrations of northern fulmars (fulmarus glacialis; n = 9), western grebes (aechmophorus occidentalis; n = 6), and common murres (uria aalge; n = 25) housed on freshwater while undergoing rehabilitation at the san francisco bay oiled wildlife care and education center in fairfield, california, ... | 2012 | 23272353 |
| heavy metals and selenium in grebe feathers from agassiz national wildlife refuge in northern minnesota. | metal levels in feathers can often be used as an indicator of exposure and of potential effects in birds. in previous work at agassiz national wildlife refuge, northwestern minnesota, pied-billed grebe (podilymbus podiceps) eggs had significantly higher levels of manganese and mercury and significantly lower levels of selenium than eared (podiceps nigricollis) or red-necked grebes (podiceps grisegena), but in 1999, pied-billed grebes had significantly higher levels of mercury, but lower levels o ... | 2007 | 17657451 |
| organochlorine contaminants and eggshell thinning in grebes from prairie canada. | eggs of five species of grebe were collected from manitoba, saskatchewan and alberta during 1982-1987: red-necked (podiceps grisegena), horned (p. auritus), eared (p. caspicus), western (aechmophorus occidentalis) and pied-billed (podilymbus podiceps). dde and pcbs were present in all samples analyzed, whereas dieldrin, mirex and oxychlordane were occasionally present at low levels. mercury was present at low levels in all samples for which it was analyzed. red-necked grebes nesting in manitoba ... | 1994 | 15091684 |
| functional relationships and microhabitat distributions of enteric helminths of grebes (podicipedidae): the evidence for interactive communities. | the significance of interspecific interactions as a structuring force in the enteric helminth communities of 4 species of grebes (aechmophorus occidentalis, podiceps grisegena, p. nigricollis, and p. auritus) was evaluated. patterns of microhabitat distribution revealed that helminths resided in predictable locations along the length of the small intestine. individual species of helminths occupied a high proportion of the intestine and varied in position in different host species suggesting a br ... | 1988 | 3357112 |
| effects of dde, tde, and pcbs on shell thickness of western grebe eggs, bear river migratory bird refuge, utah--1973-74. | dde, tde, and polychlorinated biphenyls (pcbs) as aroclors 1260 and 1254 were detected in low concentrations in eggs of western grebes (aechmophorus occidentalis) from bear river migratory bird refuge, utah. dde was the only contaminant which was both negatively correlated with eggshell thickness and a significant variable in a multiple regression model for predicting eggshell thickness. the eggshell thickness index for western grebe decreased 2.3 percent from pre- to post-ddt-use periods. incub ... | 1980 | 6780970 |
| estimation and testing of parameters in richards growth model for western grebes. | growth rate coefficients for dark- and light-phase western grebes (aechmophorus occidentalis) are compared with the richards' growth model. the statistical assumptions necessary to estimate and test parameters are carefully scrutinized. autocorrelations of the residuals are removed with an autoregressive model, and heterogeneity of variance of the residuals is corrected with weighted least squares. a model allowing random variation in the process of growth is also suggested as being a more reali ... | 1977 | 604186 |
| effects of added lipids on digestibility and nitrogen balance in oiled common murres ( uria aalge ) and western grebes ( aechmophorus occidentalis ) fed four formulations of a critical care diet. | nutritional support is a primary therapy administered to oiled animals during responses to oil spills, but data informing nutritional decision-making during events are limited. in this study, 44 common murres ( uria aalge ) and 6 western grebes ( aechmophorus occidentalis ), naturally oiled by oceanic seeps off the coast of ventura and santa barbara counties, ca, usa, were assigned to 1 of 4 groups fed diets with varying levels (6.8% [no added oil], 11%, and 20%) and types (salmon, corn) of oil ... | 2017 | 28644081 |
| season, molt, and body size influence mercury concentrations in grebes. | we studied seasonal and physiological influences on mercury concentrations in western grebes (aechmophorus occidentalis) and clark's grebes (a. occidentalis) across 29 lakes and reservoirs in california, usa. additionally, at three of these lakes, we conducted a time series study, in which we repeatedly sampled grebe blood mercury concentrations during the spring, summer, and early fall. grebe blood mercury concentrations were higher among males (0.61 ± 0.12 μg/g ww) than females (0.52 ± 0.10 μg ... | 2017 | 28577380 |
| using citizen-science data to identify local hotspots of seabird occurrence. | seabirds have been identified and used as indicators of ecosystem processes such as climate change and human activity in nearshore ecosystems around the globe. temporal and spatial trends have been documented at large spatial scales, but few studies have examined more localized patterns of spatiotemporal variation, by species or functional group. in this paper, we apply spatial occupancy models to assess the spatial patchiness and interannual trends of 18 seabird species in the puget sound regio ... | 2015 | 25653898 |
| humans running in place on water at simulated reduced gravity. | on earth only a few legged species, such as water strider insects, some aquatic birds and lizards, can run on water. for most other species, including humans, this is precluded by body size and proportions, lack of appropriate appendages, and limited muscle power. however, if gravity is reduced to less than earth's gravity, running on water should require less muscle power. here we use a hydrodynamic model to predict the gravity levels at which humans should be able to run on water. we test thes ... | 2012 | 22815681 |
| exploring the genetic diversity of tylodelphys (diesing, 1850) metacercariae in the cranial and body cavities of mexican freshwater fishes using nuclear and mitochondrial dna sequences, with the description of a new species. | members of the genus tylodelphys diesing, 1850 are endoparasites of fish-eating birds, particularly ciconiids, anhingids, and podicipedids across the globe. metacercariae of tylodelphys spp. were collected from the cranial and body cavities of freshwater fishes in central and northern mexico; adults were recovered from the intestine of two species of freshwater diving birds of the family podicipedidae, commonly known as grebes, in two locations of central mexico. specimens were sequenced for two ... | 2019 | 30552574 |