Dietary Overlap Between Sympatric Mexican Spotted and Great Horned Owls in Arizona PDF Download
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Author: Joseph L. Ganey
Publisher:
ISBN:
Category : Great horned owl
Languages : en
Pages : 26
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Book Description
We estimated diet composition of sympatric Mexican spotted (Strix occidentalis lucida, n = 7 pairs of owls) and great horned owls (Bubo virginianus, n = 4 pairs) in ponderosa pine (Pinus ponderosa) - Gambel oak (Quercus gambelii) forest, northern Arizona. Both species preyed on mammals, birds, and insects; great horned owls also ate lizards. Mammals dominated the diet of both species. Mammals comprised 63 and 62% of all prey items identified in diets of spotted and great horned owls, respectively, and 94 and 95% of prey biomass. Both species primarily preyed on a few groups of small mammals. Observed overlap in diet composition between species (0.95) was greater than expected based on null models of diet overlap, and the size range of prey taken overlapped entirely. Mean prey mass was similar for both species (great horned owl, 47.0 ± 7.4 g [SE], n = 94 items; spotted owl, 40.1 ± 1.8 g, n = 1,125 items). Great horned owls consumed larger proportions of diurnally active prey than spotted owls, which primarily consumed nocturnally active mammals. Our results, coupled with a previous analysis showing that these owls foraged in the same general areas (Ganey and others 1997), suggests that they could compete for food resources, which are assumed to be limiting in at least some years. They may minimize the potential for resource competition, however, by concentrating foraging activities in different habitats (Ganey and others 1997) and by foraging at different times, when different suites of prey species are active.
Author: Joseph L. Ganey
Publisher:
ISBN:
Category : Great horned owl
Languages : en
Pages : 26
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Book Description
We estimated diet composition of sympatric Mexican spotted (Strix occidentalis lucida, n = 7 pairs of owls) and great horned owls (Bubo virginianus, n = 4 pairs) in ponderosa pine (Pinus ponderosa) - Gambel oak (Quercus gambelii) forest, northern Arizona. Both species preyed on mammals, birds, and insects; great horned owls also ate lizards. Mammals dominated the diet of both species. Mammals comprised 63 and 62% of all prey items identified in diets of spotted and great horned owls, respectively, and 94 and 95% of prey biomass. Both species primarily preyed on a few groups of small mammals. Observed overlap in diet composition between species (0.95) was greater than expected based on null models of diet overlap, and the size range of prey taken overlapped entirely. Mean prey mass was similar for both species (great horned owl, 47.0 ± 7.4 g [SE], n = 94 items; spotted owl, 40.1 ± 1.8 g, n = 1,125 items). Great horned owls consumed larger proportions of diurnally active prey than spotted owls, which primarily consumed nocturnally active mammals. Our results, coupled with a previous analysis showing that these owls foraged in the same general areas (Ganey and others 1997), suggests that they could compete for food resources, which are assumed to be limiting in at least some years. They may minimize the potential for resource competition, however, by concentrating foraging activities in different habitats (Ganey and others 1997) and by foraging at different times, when different suites of prey species are active.
Author:
Publisher:
ISBN:
Category : Bird watching
Languages : en
Pages : 610
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Book Description
Author:
Publisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 106
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Book Description
Author: Frederick R. Gehlbach
Publisher: Texas A&M University Press
ISBN: 9781603441216
Category : Nature
Languages : en
Pages : 328
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Book Description
The eastern screech owl, widespread over the eastern half of North America and noticeably tolerant of human activity, is one of America's most familiar birds. Residing naturally in wooded environs with tree cavities, this owl lives well in suburbia and can be found nesting in mailboxes, porch columns, and purple martin houses. Based on a twenty-five-year study, biologist Frederick R. Gehlbach tells the life story of the eastern screech owl, focusing on case studies of suburban and rural study plots in Central Texas. This is the first thorough study of major life-history, behavioral, and ecological features of the species. Indeed, it is the first concurrent, comparative study of an urban and a rural population of any New World animal. Told in a personal voice, the story of these birds will interest all who have not lost touch with their ancestral world. However, Gehlbach has also included quantitative data and analysis of interest to ecologists, wildlife biologists, and ornithologists. Photographs (including color shots of the gray and rufous phases), figures, and tables provide further detail. Gehlbach's investigations have been those of not only an academic ecologist, but a suburbanite curious about his natural surroundings. The result is a model of research on species population dynamics and adaptation, yielding an emerging picture of what the eastern screech owl needs for successful coexistence with human neighbors.
Author: United States. Forest Service
Publisher:
ISBN:
Category : Birds
Languages : en
Pages : 120
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Author: Paula L. Enriquez
Publisher: Springer
ISBN: 3319571087
Category : Science
Languages : en
Pages : 673
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Book Description
This book presents a comprehensive biological and ecological information about owls in the neotropic area. In addition the book covers topics such as threats and conservation strategies for these nocturnal birds of prey from 18 Neotropical countries. Owls are a good example of diversification processes and have developed evolutionary characteristics themselves. These species are found almost everywhere in the world but most of them are distributed in tropical areas and about a third of them live in the Neotropics. This biogeographic region has a high biodiversity and even share lineages of species from other continents because at some point all were part of Pangea. Although we still have much to know and understand about this diverse, scarcely studied and threatened group this work aims to be a precedent for future and further research on the subject.
Author: Charles J. Krebs
Publisher: Benjamin-Cummings Publishing Company
ISBN: 9780321068798
Category : Science
Languages : en
Pages : 695
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Book Description
This best-selling majors ecology book continues to present ecology as a series of problems for readers to critically analyze. No other text presents analytical, quantitative, and statistical ecological information in an equally accessible style. Reflecting the way ecologists actually practice, the book emphasizes the role of experiments in testing ecological ideas and discusses many contemporary and controversial problems related to distribution and abundance. Throughout the book, Krebs thoroughly explains the application of mathematical concepts in ecology while reinforcing these concepts with research references, examples, and interesting end-of-chapter review questions. Thoroughly updated with new examples and references, the book now features a new full-color design and is accompanied by an art CD-ROM for instructors. The field package also includes The Ecology Action Guide, a guide that encourages readers to be environmentally responsible citizens, and a subscription to The Ecology Place (www.ecologyplace.com), a web site and CD-ROM that enables users to become virtual field ecologists by performing experiments such as estimating the number of mice on an imaginary island or restoring prairie land in Iowa. For college instructors and students.
Author: David J. Hafner
Publisher: IUCN
ISBN: 9782831704630
Category : Nature
Languages : en
Pages : 188
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Book Description
The first comprehensive treatment of North American rodents of conservation concern. This action plan summarizes the rodent fauna of North America and provides available information on every rodent taxon that has been considered to be of conservation concern by state, provincial and private conservation agencies and regional experts. It is hoped that the survey provided in this action plan will serve as a common ground for all these parties in drawing up conservation strategies for rodents.
Author: Tim Caro
Publisher: Island Press
ISBN: 159726959X
Category : Nature
Languages : en
Pages : 394
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Book Description
The vast scope of conservation problems has forced biologists and managers to rely on "surrogate" species to serve as shortcuts to guide their decision making. These species-known by a host of different terms, including indicator, umbrella, and flagship species-act as proxies to represent larger conservation issues, such as the location of biodiversity hotspots or general ecosystem health. Synthesizing an immense body of literature, conservation biologist and field researcher Tim Caro offers systematic definitions of surrogate species concepts, explores biological theories that underlie them, considers how surrogate species are chosen, critically examines evidence for and against their utility, and makes recommendations for their continued use. The book clarifies terminology and contrasts how different terms are used in the real world considers the ecological, taxonomic, and political underpinnings of these shortcuts identifies criteria that make for good surrogate species outlines the circumstances where the application of the surrogate species concept shows promise Conservation by Proxy is a benchmark reference that provides clear definitions and common understanding of the evidence and theory behind surrogate species. It is the first book to review and bring together literature on more than fifteen types of surrogate species, enabling us to assess their role in conservation and offering guidelines on how they can be used most effectively.
Author: Darryl I. MacKenzie
Publisher: Elsevier
ISBN: 0124072453
Category : Mathematics
Languages : en
Pages : 668
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Book Description
Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence, Second Edition, provides a synthesis of model-based approaches for analyzing presence-absence data, allowing for imperfect detection. Beginning from the relatively simple case of estimating the proportion of area or sampling units occupied at the time of surveying, the authors describe a wide variety of extensions that have been developed since the early 2000s. This provides an improved insight about species and community ecology, including, detection heterogeneity; correlated detections; spatial autocorrelation; multiple states or classes of occupancy; changes in occupancy over time; species co-occurrence; community-level modeling, and more. Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence, Second Edition has been greatly expanded and detail is provided regarding the estimation methods and examples of their application are given. Important study design recommendations are also covered to give a well rounded view of modeling. - Provides authoritative insights into the latest in occupancy modeling - Examines the latest methods in analyzing detection/no detection data surveys - Addresses critical issues of imperfect detectability and its effects on species occurrence estimation - Discusses important study design considerations such as defining sample units, sample size determination and optimal effort allocation
