6,839 research outputs found

    Book Review: Statistics in Omithology

    Get PDF
    This book, the 29th in Springer-Verlag\u27s Lecture Notes in Statistics series, arose from a one-day meeting held in London in 1982. All but two of the papers presented at that meeting are included, as are additional papers not given in London. Refereeing was done by the two editors

    Review of \u3ci\u3eThe Tallgrass Restoration Handbook: For Prairies, Savannas, and Woodlands\u3c/i\u3e Edited by Stephen Packard and Cornelia F. Mutel

    Get PDF
    Prairies have been termed the nation\u27s most endangered ecosystem. Tallgrass prairies especially have been converted to cultivation; most states have lost ninety-eight percent or more of the tallgrass prairie that existed before European settlement. The rich soils that tallgrass vegetation created over millennia led to the prairies\u27 replacement by the Corn Belt in a matter of mere decades. While most persons, rather than mourning the passing of tallgrass prairie, are contented with the vistas of grains and soybeans that displaced it, some conservationists are attempting to stem the tide of habitat loss, and others are going so far as trying to restore or recreate grasslands. The Tallgrass Restoration Handbook is intended for this latter group

    Estimating Survival Rates from Banding of Adult and Juvenile Birds

    Get PDF
    The restrictive assumptions required by most available methods for estimating survival prob- abilities render them unsuitable for analyzing real banding data. A model is proposed which allows survival rates and recovery rates to vary with the calendar year, and also allows juveniles to have rates different from adults. In addition to survival rates and recovery rates, the differential vulnerability factors of juveniles relative to adults are estimated. Minimum values of the variances of the estimators are also given. The new procedure is applied to sets of duck and goose data in which reasonably large numbers of adult and juvenile birds were banded. The results are shown to be generally comparable to those procured by other methods, but, in addition, insight into the extent of annual variation is gained. Combining data from adults and juveniles also increases the effective sample size, since the juveniles are assumed to enter the adult age class after surviving their initial year

    Book Review: Research Techniques in Animal Ecology: Controversies and Consequences

    Get PDF
    This edited volume covers a number of techniques widely used in animal ecology. It is intended not so much as a handbook, though, as a critique. Authors of each chapter present an overview of the techniques pertinent to the topic of that chapter, then point out weaknesses and strengths of those techniques. This book is the result of a workshop held in Sicily in late 1996, which involved a small group of scientists and a limited audience of 75. The authors, noted European and North American scientists, have clearly expended the effort to synthesize a lot of information for the reader

    Review of \u3ci\u3eThe Tallgrass Restoration Handbook: For Prairies, Savannas, and Woodlands\u3c/i\u3e Edited by Stephen Packard and Cornelia F. Mutel

    Get PDF
    Prairies have been termed the nation\u27s most endangered ecosystem. Tallgrass prairies especially have been converted to cultivation; most states have lost ninety-eight percent or more of the tallgrass prairie that existed before European settlement. The rich soils that tallgrass vegetation created over millennia led to the prairies\u27 replacement by the Corn Belt in a matter of mere decades. While most persons, rather than mourning the passing of tallgrass prairie, are contented with the vistas of grains and soybeans that displaced it, some conservationists are attempting to stem the tide of habitat loss, and others are going so far as trying to restore or recreate grasslands. The Tallgrass Restoration Handbook is intended for this latter group

    A theoretical and numerical approach to "magic angle" of stone skipping

    Full text link
    We investigate oblique impacts of a circular disk and water surface. An experiment [ Clanet, C., Hersen, F. and Bocquet, L., Nature 427, 29 (2004) ] revealed that there exists a "magic angle" of 20 [deg.] between a disk face and water surface which minimize the required speed for ricochet. We perform 3-dimensional simulation of the water impacts using the Smoothed Particle Hydrodynamics (SPH) and analyze the results with an ordinal differential equation (ODE) model. Our simulation is in good agreement with the experiment. The analysis with the ODE model give us a theoretical insight for the ``magic angle" of stone skipping.Comment: 4 pages, 4figure

    Conditioning of Sandhill Cranes During Fall Migration

    Get PDF
    Body mass of adult female and male sandhill cranes (Grus canadensis) increased an average of 17 and 20%, respectively, from early September to late October on staging areas in central North Dakota and varied by year. Increases in body mass averaged 550 and 681 g among female and male G. c. canadensis, respectively, and 616 and 836 g among female and male G. c. rowani. Adult and juvenile G. c. rowani were lean at arrival, averaging 177 and 83 g of fat, respectively, and fat reserves increased to 677 and 482 g by mid-October. Fat-free dry mass increased by 12% among juveniles, reflecting substantial growth, but remained constant among adults. The importance of fall staging areas as conditioning sites for sandhill cranes, annual variation in body mass, and vulnerability of cranes to habitat loss underscore the need to monitor status of fall staging habitat in the northern plains region and to take steps to maintain suitable habitat where necessary

    Dramatic Increase of Le Conte\u27s Sparrow in Conservation Reserve Program Fields in the Northern Great Plains

    Get PDF
    During a continuing investigation in the northern Great Plains, we documented substantial increases of the Le Conte\u27s Sparrow (Ammodramus Leconteii) in Conservation Reserve Program (CRP) fields in 1994 compared with 1990-93. The most dramatic increases occurred in Eddy County, North Dakota, and Sheridan County, Montana. The changes in habitat associated with the drought from 1989 to early 1993 and above-normal precipitation from mid-1993 through mid-1994 likely produced favorable breeding conditions for this species in CRP fields in 1994

    AREA REQUIREMENTS OF GRASSLAND BIRDS: A REGIONAL PERSPECTIVE

    Get PDF

    Brown-headed Cowbird, Molothrus ater, Parasitism and Abundance in the Northern Great Plains

    Get PDF
    The Brown-headed Cowbird (Molothrus ater) reaches its highest abundance in the northern Great Plains, but much of our understanding of cowbird ecology and host-parasite interactions comes from areas outside of this region. We examine cowbird brood parasitism and densities during two studies of breeding birds in the northern Great Plains during 1990–2006. We found 2649 active nests of 75 species, including 746 nonpasserine nests and 1902 passerine nests. Overall, <1% of nonpasserine nests and 25% of passerine nests were parasitized by Brown-headed Cowbirds. Although the overall frequency of cowbird parasitism in passerine nests in these two studies is considered moderate, the frequency of multiple parasitism among parasitized nests was heavy (nearly 50%). The mean number of cowbird eggs per parasitized passerine nest was 1.9 ± 1.2 (SD; range = 1–8 cowbird eggs). The parasitism rates were 9.5% for passerines that typically nest in habitats characterized by woody vegetation, 16.4% for grassland-nesting passerines, 4.7% for passerines known to consistently eject cowbird eggs, and 28.2% for passerines that usually accept cowbird eggs. The Red-winged Blackbird (Agelaius phoeniceus) was the most commonly parasitized species (43.1% parasitism, 49.6% multiple parasitism, 71.2% of all cases of parasitism). Passerine nests found within areas of higher female cowbird abundance experienced higher frequencies of cowbird parasitism than those found in areas of lower female cowbird abundance. Densities of female cowbirds were positively related to densities and richness of other birds in the breeding bird community
    • …
    corecore