14 research outputs found

    AN UPDATED DISTRIBUTION MAP FOR THE LOWER COLORADO RIVER VALLEY POPULATION OF GREATER SANDHILL CRANES

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    The U.S. Fish and Wildlife Service (USFWS) recognizes 6 migratory populations of sandhill cranes (Grus canadensis) in the United States, 4 of which occur in or west of the Rocky Mountains. Traditionally the Lower Colorado River Valley Population (LCRVP; greater sandhill crane [G. c. tabida]) was thought to be distributed across the Imperial (California) and Lower Colorado River (Arizona) Valleys, southward into Mexico via the Colorado River delta in winter and northeastern Nevada (Elko and White Pine Counties) during summer. Conservation and management concern exists over known distribution based on winter and summer surveys because discrepancies exist between the number of individuals counted on winter and summer termini. In 2014 the USFWS initiated a mark-recapture program on the LCRVP to aid in the development of long-term management of this least abundant greater sandhill crane population. The objective of this paper is to update the known distribution of the LCRVP from greater sandhill cranes by using platform transmitter terminals (PTTs). We captured 44 individual greater sandhill cranes and equipped 22 with PTTs on the wintering and summering grounds in the Imperial and Lower Colorado River Valleys and west-central Idaho, 2014-2015. Our updated distribution map from 18 of 22 PTT-tagged individuals identified several new summer locations extending north and west into west-central Idaho and numerous new migratory locations extending east into Utah. We also confirmed winter locations on the Gila River southwest of Phoenix, Arizona. The extent of the distribution of the LCRVP extends farther north and east than previously expected and, most importantly, overlaps with areas commonly affiliated with the Central Valley and Rocky Mountain Populations in the Intermountain West

    Identifying the migratory strategy of the Lower Colorado River Valley population of Greater Sandhill Cranes

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    Across North America, Sandhill Cranes (Antigone canadensis) use an array of migratory strategies, ranging from “jumping,” or taking 1 or 2 flights from wintering grounds to a staging area, then on to the breeding grounds, to “hopping,” or taking shorter flights among multiple (\u3e3) staging areas between termini. We captured 16 adult and 2 juvenile Greater Sandhill Cranes (Antigone canadensis tabida) from the Lower Colorado River Valley population (LCRVP) and fitted them with platform transmitter terminals (PTTs) for GPS satellite telemetry. We used recorded locations and Brownian bridge movement models (BBMMs) to identify migration corridors and areas of migratory use (AMUs) during spring and fall migration (2014-2016). Eighty-nine percent of our sample (n = 16) of LCRVP Sandhill Cranes with PTTs flew direct paths between summer and winter termini. Starting in the Great Basin and moving into the Mojave Desert and then into the Sonoran Desert, the LCRVP aligned its migration with drainages, rivers, and reservoirs. Within those direct paths, we identified 18 unique and discrete AMUs along an ∼1000-km corridor and 3 within minor corridors taken by the other 2 cranes. We defined AMU as an area within a crane’s 75% BBMM migration confidence contour where the crane had 2 or more subsequent time stamps (could be ≥3 hours) and did not travel \u3e40 km from the first time stamp. The average migration duration was 23 days (spring, n = 3; fall, n = 2; cranes, n = 53). The fact that many individuals stopped several times after relatively short flights during both migration seasons suggests that the LCRVP generally uses a “hop” migration strategy. The use, often frequent and consecutive, of the 21 AMUs in this research reveals the potential importance of these migration areas to the LCRVP for its social, behavioral, and energetic requirements during migration

    AN UPDATED DISTRIBUTION MAP FOR THE LOWER COLORADO RIVER VALLEY POPULATION OF GREATER SANDHILL CRANES

    Get PDF
    The U.S. Fish and Wildlife Service (USFWS) recognizes 6 migratory populations of sandhill cranes (Grus canadensis) in the United States, 4 of which occur in or west of the Rocky Mountains. Traditionally the Lower Colorado River Valley Population (LCRVP; greater sandhill crane [G. c. tabida]) was thought to be distributed across the Imperial (California) and Lower Colorado River (Arizona) Valleys, southward into Mexico via the Colorado River delta in winter and northeastern Nevada (Elko and White Pine Counties) during summer. Conservation and management concern exists over known distribution based on winter and summer surveys because discrepancies exist between the number of individuals counted on winter and summer termini. In 2014 the USFWS initiated a mark-recapture program on the LCRVP to aid in the development of long-term management of this least abundant greater sandhill crane population. The objective of this paper is to update the known distribution of the LCRVP from greater sandhill cranes by using platform transmitter terminals (PTTs). We captured 44 individual greater sandhill cranes and equipped 22 with PTTs on the wintering and summering grounds in the Imperial and Lower Colorado River Valleys and west-central Idaho, 2014-2015. Our updated distribution map from 18 of 22 PTT-tagged individuals identified several new summer locations extending north and west into west-central Idaho and numerous new migratory locations extending east into Utah. We also confirmed winter locations on the Gila River southwest of Phoenix, Arizona. The extent of the distribution of the LCRVP extends farther north and east than previously expected and, most importantly, overlaps with areas commonly affiliated with the Central Valley and Rocky Mountain Populations in the Intermountain West

    Summer Habitat Selection of the Lower Colorado River Valley Population of Greater Sandhill Cranes

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    Identifying habitat selection and use is important to understand in wildlife management because it informs habitat manipulations, conservation efforts, and species distribution. Habitat selection by sandhill cranes (Antigone canadensis) has been studied primarily on overwintering areas and a few summering locations. Summer habitat selection by the Lower Colorado River Valley Population of greater sandhill cranes (A. c. tabida) in the Intermountain West is not widely known, but has been identified as an information need by many wildlife management agencies. We captured and attached satellite platform transmitter terminals to 21 adult sandhill cranes on Cibola and Sonny Bono Salton Sea National Wildlife Refuges in Arizona and California, and private lands in California and Idaho. Home ranges of all marked cranes (50% core area: ¯x¼525.4 ha, SE¼155.6; 99% isopleth: ¯x¼6,476.5 ha, SE¼1,637.5) were similar to other studies on summering grounds. Resource analysis indicated that marked sandhill cranes used wetland habitats in greater proportion than their availability for both nocturnal and diurnal locations at the population level, by individuals within the entire landscape, and by individuals within their core area. Wetland habitats consist of ~7% of the available habitat. Within the Wetland category, the Temperate Flooded and Swamp Forest level (a Formation level in the National Vegetation Classification system) was the most important to summering Lower Colorado River Population sandhill cranes. Wetland managers can concentrate their efforts for conservation, enhancement, and restoration on these type of wetlands to ensure the sustainability of this small population of sandhill cranes

    Identifying the migratory strategy of the Lower Colorado River Valley population of Greater Sandhill Cranes

    No full text
    Across North America, Sandhill Cranes (Antigone canadensis) use an array of migratory strategies, ranging from "jumping," or taking 1 or 2 flights from wintering grounds to a staging area, then on to the breeding grounds, to "hopping," or taking shorter flights among multiple (>3) staging areas between termini. We captured 16 adult and 2 juvenile Greater Sandhill Cranes (Antigone canadensis tabida) from the Lower Colorado River Valley population (LCRVP) and fitted them with platform transmitter terminals (PTTs) for GPS satellite telemetry. We used recorded locations and Brownian bridge movement models (BBMMs) to identify migration corridors and areas of migratory use (AMUs) during spring and fall migration (2014-2016). Eighty-nine percent of our sample (n = 16) of LCRVP Sandhill Cranes with PTTs flew direct paths between summer and winter termini. Starting in the Great Basin and moving into the Mojave Desert and then into the Sonoran Desert, the LCRVP aligned its migration with drainages, rivers, and reservoirs. Within those direct paths, we identified 18 unique and discrete AMUs along an ∼1000-km corridor and 3 within minor corridors taken by the other 2 cranes. We defined AMU as an area within a crane's 75% BBMM migration confidence contour where the crane had 2 or more subsequent time stamps (could be ≥3 hours) and did not travel >40 km from the first time stamp. The average migration duration was 23 days (spring, n = 3; fall, n = 2; cranes, n = 53). The fact that many individuals stopped several times after relatively short flights during both migration seasons suggests that the LCRVP generally uses a "hop" migration strategy. The use, often frequent and consecutive, of the 21 AMUs in this research reveals the potential importance of these migration areas to the LCRVP for its social, behavioral, and energetic requirements during migration

    Summer Habitat Selection of the Lower Colorado River Valley Population of Greater Sandhill Cranes

    No full text
    Identifying habitat selection and use is important to understand in wildlife management because it informs habitat manipulations, conservation efforts, and species distribution. Habitat selection by sandhill cranes (Antigone canadensis) has been studied primarily on overwintering areas and a few summering locations. Summer habitat selection by the Lower Colorado River Valley Population of greater sandhill cranes (A. c. tabida) in the Intermountain West is not widely known, but has been identified as an information need by many wildlife management agencies. We captured and attached satellite platform transmitter terminals to 21 adult sandhill cranes on Cibola and Sonny Bono Salton Sea National Wildlife Refuges in Arizona and California, and private lands in California and Idaho. Home ranges of all marked cranes (50% core area: ¯x¼525.4 ha, SE¼155.6; 99% isopleth: ¯x¼6,476.5 ha, SE¼1,637.5) were similar to other studies on summering grounds. Resource analysis indicated that marked sandhill cranes used wetland habitats in greater proportion than their availability for both nocturnal and diurnal locations at the population level, by individuals within the entire landscape, and by individuals within their core area. Wetland habitats consist of ~7% of the available habitat. Within the Wetland category, the Temperate Flooded and Swamp Forest level (a Formation level in the National Vegetation Classification system) was the most important to summering Lower Colorado River Population sandhill cranes. Wetland managers can concentrate their efforts for conservation, enhancement, and restoration on these type of wetlands to ensure the sustainability of this small population of sandhill cranes

    What does it mean to be an Empiricist in Medicine ? Baglivi’s Praxis Medica (1696)

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    International audienceHow are we to connect the mechanist methodology used by Baglivi in his physiological treatises with the apparently strict empiricism that he promotes in his therapeutic work entitled Practice of Physick, reduc’d to the Ancient Way of Observations? In order to answer this question, we examine the methodological implications of the “history of diseases” that Baglivi promotes by using Bacon’s recommendations in the Novum organum. Then, we compare this result with the place that historians generally gave to Baglivi in the medical context of that time: the place of a dogmatic and “iatromechanist” physician who was far from practical and therapeutic concerns. This confrontation allows us first to apprehend the polemical origin of the so-called “iatromechanism” as a historiographical label, and second, to question the preeminence of the role of observations in the shaping of the classical distinction between “rational” physicians and “empirical” ones. When Early Modern physicians use the dichotomy between “empirical” and “rationalist” in order to discredit what they perceive as oversimplification or dogmatism, there is most often a third group at stake; a group which is depicted as the providential and intelligent solution to sectarianism. For Baglivi, this third group would be an “Empirick rational sect.” The distinction between a medicina prima and a medicina secunda allows us to understand such an apparently paradoxical category
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