189 research outputs found

    ā€œNew Bottles Made with My Crestā€: Colonial Bottle Seals from Eastern North America, a Gazetteer and Interpretation

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    Bottle seals or crests are one of the more intriguing categories of artifacts recovered from historic archaeological sites. These small blobs of glass were applied to the necks or shoulders of bottles. They were embossed with initials, shields, and other insignia. They bear dates, as well as the initials and names of individuals and families, taverns, vineyards, schools, retailers, and military units. Archaeologists seriating blown glass bottles from colonial sites in North America have employed them as important dating tools. They have also been interpreted as status markers. This paper provides a gazetteer of bottles with seals from eastern North America. It also argues that private seals, bottle seals employed by individuals rather than organizations, served as indicators of economic, social, and cultural capital in early America. They provide insights into various aspects of colonial culture, including the creation and maintenance of male identities, membership in elite groups, and knowledge of proper etiquette. Furthermore, the geographic disparities in their distribution serve to highlight the development of distinctive regional cultures. These simple seals provide a window into lifeways in colonial America and the aspirations, behaviors, and connections between the owners of vintages consumed long ago

    Broadscale density and aggregation of pelagic birds from circumnavigational survey of the Antarctic Ocean

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    We analyzed the spatial distribution and habitat relationships of pelagic birds on a circumnavigational cruise of Antarctica. Our analysis focused on two issues. First, we present a quantitative description of the structure of Antarctic seabird assemblages. This descriptive information benefits from a much more longitudinally extensive data set than previously available. Second, we used 18 crossings of the edge of the pack ice and 15 crossings of the continental slope to clarify the spatial relationship between aggregations of pelagic birds and these physical features. Our analysis corroborates the uniformity of bird species composition over the longitudinal range we covered. We found that the habitats with light (2/10 to 6/10 coverage) pack-ice cover had the lowest density and biomass of birds of the four ice habitats (open water, icebergs only, light pack ice, heavy pack ice) surveyed. Even though overall bird abundance was not concentrated at the ice edge, aggregations of individual species were statistically likely to appear there. We found only a slight (34%) elevation in bird biomass over the continental slope, despite repeated previous findings of bird aggregations associated with the Antarctic slope front. Finally, 45% of the seabirds we observed were in three large aggregations. We suggest this concentration demonstrates the importance of localized patches of prey to foraging seabirds in the Antarctic

    Ocean warming and long-term change in pelagic bird abundance within the California current system

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    As a result of repeated sampling of pelagic bird abundance over 3 x 105 km2 of open ocean 4 times a year for 8 yr, we report that seabird abundance within the California Current system has declined by 40% over the period 1987 to 1994. This decline has accompanied a concurrent, long-term increase in sea surface temperature. The decline in overall bird abundance is largely, but not entirely, a consequence of the 90% decline of sooty shearwaters Puffinus griseus, the numerically dominant species of the California Current. Seabirds of the offshore waters we sampled showed a different pattern from seabirds of the shelf and slope waters. Leach's storm-petrels Oceanodroma leucorhoa, the commonest species offshore, significantly increased during 1987 to 1994, while sooty shearwaters and other inshore species declined. Thus the clearest pattern that emerges from our data is one of gradual but persistent changes in abundance that transpire at time scales longer than 1 yr. Nevertheless, we did find evidence of change at shorter time scales (weeks and months) that may relate to the El NiƱo episode of 1992 to 1993: Pronounced positive anomalies of abundance of brown pelicans Pelecanus occidentalis and Heerman's gulls Larus heermani in fall 1991, and black Oceanodroma melania andleast O. microsoma storm-petrels in late summer 1992, likely reflect northward dispersal following reproductive failure in the Gulf of California

    Climate and changing winter distribution of alcids in the Northwest Atlantic

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    Population level impacts upon seabirds from changing climate are increasingly evident, and include effects on phenology, migration, dispersal, annual survivorship, and reproduction. Most population data on seabirds derive from nesting colonies; documented climate impacts on winter ecology are scarce. We studied interannual variability in winter abundance of six species of alcids (Charadriiformes, Alcidae) from a 58-year time series of data collected in Massachusetts 1954ā€“2011. We used counts of birds taken during fall and winter from coastal vantage points. Counts were made by amateur birders, but coverage was consistent in timing and location. We found significant association between winter abundance of all six species of alcids and climate, indexed by North Atlantic Oscillation (NAO), at two temporal scales: (1) significant linear trends at the 58-year scale of the time series; and (2) shorter term fluctuations corresponding to the 5ā€“8 year periodicity of NAO. Thus, variation in winter abundance of all six species of alcids was significantly related to the combined short-term and longer-term components of variation in NAO. Two low-Arctic species (Atlantic Puffin and Black Guillemot) peaked during NAO positive years, while two high Arctic species (Dovekie and Thick-billed Murre) peaked during NAO negative years. For Common Murres and Razorbills, southward shifts in winter distribution have been accompanied by southward expansion of breeding range, and increase within the core of the range. The proximate mechanism governing these changes is unclear, but, as for most other species of seabirds whose distributions have changed with climate, seems likely to be through their prey

    Positive Interactions among Foraging Seabirds, Marine Mammals and Fishes and Implications for Their Conservation

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    There is increasing recognition of the importance of ā€œpositive interactionsā€ among species in structuring communities. For seabirds, an important kind of positive interaction is the use of birds of the same species, birds of other species, and other marine predators such as cetaceans, seals and fishes as cues to the presence of prey. The process by which a single bird uses, say, a feeding flock of birds as a cue to the presence of prey is called ā€œlocal enhancementā€ or ā€œfacilitation.ā€ There are subtly different uses of each of these terms, but the issue we address here is the ubiquity of positive interactions between seabirds and other marine predators when foraging at sea, and whether as a result of their associations the feeding success, and therefore presumably the fitness, of individual seabirds is increased. If this contention is true, then it implies that conservation of any one species of seabird must take into consideration the status and possible conservation of those species that the focal species uses as a cue while foraging. For example, conservation of great shearwaters (Ardenna gravis), which often feed over tuna (e.g., Thunnus) schools, should take in to consideration conservation of tuna. Ecosystem management depends on understanding the importance of such processes; the loss of biodiversity, and the consequent threat to foraging success, may be a substantial threat to the stability of marine ecosystems

    Climate and changing winter distribution of alcids in the Northwest Atlantic

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    Population level impacts upon seabirds from changing climate are increasingly evident, and include effects on phenology, migration, dispersal, annual survivorship, and reproduction. Most population data on seabirds derive from nesting colonies; documented climate impacts on winter ecology are scarce. We studied interannual variability in winter abundance of six species of alcids (Charadriiformes, Alcidae) from a 58-year time series of data collected in Massachusetts 1954ā€“2011. We used counts of birds taken during fall and winter from coastal vantage points. Counts were made by amateur birders, but coverage was consistent in timing and location. We found significant association between winter abundance of all six species of alcids and climate, indexed by North Atlantic Oscillation (NAO), at two temporal scales: (1) significant linear trends at the 58-year scale of the time series; and (2) shorter term fluctuations corresponding to the 5ā€“8 year periodicity of NAO. Thus, variation in winter abundance of all six species of alcids was significantly related to the combined short-term and longer-term components of variation in NAO. Two low-Arctic species (Atlantic Puffin and Black Guillemot) peaked during NAO positive years, while two high Arctic species (Dovekie and Thick-billed Murre) peaked during NAO negative years. For Common Murres and Razorbills, southward shifts in winter distribution have been accompanied by southward expansion of breeding range, and increase within the core of the range. The proximate mechanism governing these changes is unclear, but, as for most other species of seabirds whose distributions have changed with climate, seems likely to be through their prey

    Wind field and sex constrain the flight speeds of central-place foraging albatrosses

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    By extracting energy from the highly dynamic wind and wave fields that typify pelagic habitats, albatrosses are able to proceed almost exclusively by gliding flight. Although energetic costs of gliding are low, enabling breeding albatrosses to forage hundreds to thousands of kilometers from their colonies, these and time costs vary with relative wind direction. This causes albatrosses in some areas to route provisioning trips to avoid headwind flight, potentially limiting habitat accessibility during the breeding season. In addition, because female albatrosses have lower wing loadings than males, it has been argued that they are better adapted to flight in light winds, leading to sexual segregation of foraging areas. We used satellite telemetry and immersion logger data to quantify the effects of relative wind speed, sex, breeding stage, and trip stage on the ground speeds (Vg) of four species of Southern Ocean albatrosses breeding at South Georgia. Vg was linearly related to the wind speed component in the direction of flight (Vwf), its effect being greatest on Wandering Albatrosses Diomedea exulans, followed by Black-browed Albatrosses Thalassarche melanophrys, Light-mantled Sooty Albatrosses Phoebatria palpebrata, and Gray-headed Albatrosses T. chrysostoma. Ground speeds at Vwf = 0 were similar to airspeeds predicted by aerodynamic theory and were higher in males than in females. However, we found no evidence that this led to sexual segregation, as males and females experienced comparable wind speeds during foraging trips. Black-browed, Gray-headed, and Light-mantled Sooty Albatrosses did not engage in direct, uninterrupted bouts of flight on moonless nights, but Wandering Albatrosses attained comparable Vg night and day, regardless of lunar phase. Relative flight direction was more important in determining Vg than absolute wind speed. When birds were less constrained in the middle stage of foraging trips, all species flew predominantly across the wind. However, in some instances, commuting birds encountered headwinds during outward trips and tail winds on their return, with the result that Vg was 1.0ā€“3.4 m/s faster during return trips. This, we hypothesize, could result from constraints imposed by the location of prey resources relative to the colony at South Georgia or could represent an energy optimization strategy

    Use of plumage and gular pouch color to evaluate condition of oil spill rehabilitated California brown pelicans (Pelecanus occidentalis californicus) post-release

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    Sublethal effects of oil spills may dampen seabird rehabilitation success due to lingering negative impacts of contamination and stress on reproduction and long-term survival. These effects can be difficult to measure while birds are in care as well as once birds are released. Expression of sexually selected traits that are sensitive to condition can provide information on physiological status of birds. We evaluated plumage molt and gular pouch skin color of California brown pelicans (Pelecanus occidentalis californicus) following oil contamination and rehabilitation to test for differences between previously oiled and rehabilitated (post-spill) and presumably uncontaminated pelicans. Post-spill pelicans released with either color leg bands alone, or bands plus harness-mounted satellite GPS tags, were relocated and visually assessed in the field at non-breeding communal roosts and compared to surrounding unmarked pelicans in the general population. Non-oiled pelicans bearing GPS tags were also included in the study. Post-spill pelicans lagged the general population in molt of ornamental yellow crown feathers but hind neck transition into white plumage was not significantly different. Both post-spill and non-oiled pelicans wearing GPS tags had lower gular redness scores than the unmarked, non-oiled population. Pre-breeding gular pouch redness of post-spill pelicans was more strongly influenced by wearing of a GPS tag than a history of oil contamination and rehabilitation. Gular pouch redness of post-spill pelicans in the first 18 months after release was positively correlated with long term survivorship. If gular pouch color is a condition-dependent sexual signal and overall health influences plumage molt progression, our results indicate that many post-spill pelicans marked with bands alone were in relatively good condition going into the next breeding season, but those released with electronic tags experienced additional stress due to wearing the equipment, introducing a confounding variable to the post-release study

    Use of plumage and gular pouch color to evaluate condition of oil spill rehabilitated California brown pelicans (Pelecanus occidentalis californicus) post-release

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    Sublethal effects of oil spills may dampen seabird rehabilitation success due to lingering negative impacts of contamination and stress on reproduction and long-term survival. These effects can be difficult to measure while birds are in care as well as once birds are released. Expression of sexually selected traits that are sensitive to condition can provide information on physiological status of birds. We evaluated plumage molt and gular pouch skin color of California brown pelicans (Pelecanus occidentalis californicus) following oil contamination and rehabilitation to test for differences between previously oiled and rehabilitated (post-spill) and presumably uncontaminated pelicans. Post-spill pelicans released with either color leg bands alone, or bands plus harness-mounted satellite GPS tags, were relocated and visually assessed in the field at non-breeding communal roosts and compared to surrounding unmarked pelicans in the general population. Non-oiled pelicans bearing GPS tags were also included in the study. Post-spill pelicans lagged the general population in molt of ornamental yellow crown feathers but hind neck transition into white plumage was not significantly different. Both post-spill and non-oiled pelicans wearing GPS tags had lower gular redness scores than the unmarked, non-oiled population. Pre-breeding gular pouch redness of post-spill pelicans was more strongly influenced by wearing of a GPS tag than a history of oil contamination and rehabilitation. Gular pouch redness of post-spill pelicans in the first 18 months after release was positively correlated with long term survivorship. If gular pouch color is a condition-dependent sexual signal and overall health influences plumage molt progression, our results indicate that many post-spill pelicans marked with bands alone were in relatively good condition going into the next breeding season, but those released with electronic tags experienced additional stress due to wearing the equipment, introducing a confounding variable to the post-release study

    The development of sentence-interpretation strategies in monolingual German-learning children with and without specific language impairment

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    Previous research on sentence comprehension conducted with German-learning children has concentrated on the role of case marking and word order in typically developing children. This paper compares, the performance of German-learning children with language impairment (age 4-6 years) and without language impairment (aged 2-6, 8-9 years) in two experiments that systematically vary the cues animacy, case marking; word-order, and subject-verb agreement. The two experiments differ with regard to the choice of case marking: in the first it is distinct but in the second it is neutralized. The theoretical framework is the competition model developed by Bates and Mac Whinney and their collaborators, a variant of the parallel distributed processing models. It is hypothesized that children of either population first appreciate the cue animacy that can be processed locally, that is, "on the spot," before they turn to more distributed cues leading ultimately up to subject-verb agreement, which presupposes the comparison of various constituents before an interpretation can be established. Thus agreement is more "costly" in processing than animacy or the (more) local cue initial NP. In experiment I with unambiguous case markers it is shown that the typically developing children proceed from animacy to the nominative (predominantly in coalition with the initial NP) to agreement, while in the second experiment with ambiguous case markers these children turn from animacy to the initial NP and then to agreement. The impaired children also progress from local to distributed cues. Yet, in contrast to the control group, they do not acknowledge the nominative in coalition with the initial NP in the first experiment but only in support of agreement. However, although they do not seem to appreciate distinct case markers to any large extent in the first experiment, they are irritated if such distinctions are lacking: in experiment II all impaired children turn to. animacy (some in coalition with the initial NP and/or particular word orders). In the discussion, the relationship between short-term memory and processing as well as the relationship between production and comprehension of case markers and agreement are addressed. Further research is needed to explore in more detail "cue costs" in sentence comprehension
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