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Author: David W. Crowley
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 128
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Book Description
Breeding habitat of Harlequin ducks (Histrionicus histrionicus) was studied in eastern Prince William Sound, Alaska, during 1991 - 1993. Streams in Prince William Sound were surveyed for Harlequin ducks and monitored with mist nets. Physical characteristics of 24 Harlequin breeding streams were compared to those of 24 streams not used for breeding using 2 sample, principal components and logistic regression analyses. Nests were located using radio-telemetry of marked females. Harlequin ducks resident in eastern Prince William Sound selected the largest anadromous salmon streams available for nesting. Volume discharge of breeding streams averaged 3.2 m3/s and was the most important factor in habitat variation between streams used and not used by breeding Harlequins. Expansive estuaries and intertidal deltas present at the outflow of large streams were important foraging and loafing areas of Harlequin ducks. Although nesting females generally avoided smaller salmon streams their intertidal estuaries were often used for foraging by females and molting males. The largest streams in Prince William Sound, glacially fed rivers, were not used by breeding Harlequins. Ten nest sites of Harlequin ducks in eastern Prince William Sound were located on southwest facing, steeply sloping banks of small, first order tributaries near timberline elevation. Nests were associated with woody debris and shrubs, in shallow depressions or cavities, and were beneath the canopy of old growth forest. Microhabitat produced by a southwest aspect, snow shadow provided by the forest canopy, and sloping stream bank may provide nesting sites earlier in the spring compared to surrounding areas.
Author: David W. Crowley
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 128
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Book Description
Breeding habitat of Harlequin ducks (Histrionicus histrionicus) was studied in eastern Prince William Sound, Alaska, during 1991 - 1993. Streams in Prince William Sound were surveyed for Harlequin ducks and monitored with mist nets. Physical characteristics of 24 Harlequin breeding streams were compared to those of 24 streams not used for breeding using 2 sample, principal components and logistic regression analyses. Nests were located using radio-telemetry of marked females. Harlequin ducks resident in eastern Prince William Sound selected the largest anadromous salmon streams available for nesting. Volume discharge of breeding streams averaged 3.2 m3/s and was the most important factor in habitat variation between streams used and not used by breeding Harlequins. Expansive estuaries and intertidal deltas present at the outflow of large streams were important foraging and loafing areas of Harlequin ducks. Although nesting females generally avoided smaller salmon streams their intertidal estuaries were often used for foraging by females and molting males. The largest streams in Prince William Sound, glacially fed rivers, were not used by breeding Harlequins. Ten nest sites of Harlequin ducks in eastern Prince William Sound were located on southwest facing, steeply sloping banks of small, first order tributaries near timberline elevation. Nests were associated with woody debris and shrubs, in shallow depressions or cavities, and were beneath the canopy of old growth forest. Microhabitat produced by a southwest aspect, snow shadow provided by the forest canopy, and sloping stream bank may provide nesting sites earlier in the spring compared to surrounding areas.
Author: David W. Crowley
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 83
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Book Description
Author: Kenneth A. Dzinbal
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 178
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Book Description
Harlequin ducks (Histrionicus histrionicus) were observed during the summers of 1979 and 1980 in Sawmill Bay, northeast Prince William Sound, Alaska. Harlequins were associated with a short, medium gradient, non-glacial stream (Stellar Creek) also used by salmon. Although harlequins nested along Stellar Creek, they apparently did not establish home ranges there during the prenesting period, and both courtship and copulation occurred in the bay. Pairs were most numerous.in the bay in mid-late May; 15 pairs were recorded in 1979, and 14 pairs were observed in 1980. Laying occurred from about 26 May - 17 June, and hatching took place from 3-15 July. Females lost weight during the incubation period, but gained weight the remainder of the. summer. The non-breeding frequency among females was estimated as 47% in 1979 and 50% in 1980. The application of patagial tags, however, appeared to reduce production. Following nesting, males generally deserted Sawmill Bay for comparatively exposed moulting areas, Females mostly remained in the bay until midlate August. Use of habitats by harlequins varied with time of day, and activity budgets varied with habitat. Paired harlequins during prenesting and laying (10 May - 21 June) spent about 47% of their time near rocks and headlands, and about 26% of their time each in Stellar Creek and in lee (i.e. protected) waters. Unpaired harlequins (22 June - 15 August) were rare in lee waters (
Author: Samuel Merrick Patten
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 24
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Author: Charles F. Thompson
Publisher: Springer Science & Business Media
ISBN: 1441964215
Category : Science
Languages : en
Pages : 201
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Book Description
Current Ornithology publishes authoritative, up-to-date, scholarly reviews of topics selected from the full range of current research in avian biology. Topics cover the spectrum from the molecular level of organization to population biology and community ecology. The series seeks especially to review (1) fields in which an abundant recent literature will benefit from synthesis and organization, or (2) newly emerging fields that are gaining recognition as the result of recent discoveries or shifts in perspective, or (3) fields in which students of vertebrates may benefit from comparisons of birds with other classes. All chapters are invited, and authors are chosen for their leadership in the subjects under review.
Author: Paul Johnsgard
Publisher: Lulu.com
ISBN: 1609621069
Category : Nature
Languages : en
Pages : 258
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Book Description
The 21 species of sea ducks are one of the larger subgroups (Tribe Mergini) of the waterfowl family Anatidae, and the 16 species (one historically extinct) that are native to North America represent the largest number to be found on any continent, and also the largest number of endemic sea duck species native to any continent. Although generally not important as game birds, the sea ducks include some economically important birds such as the eiders, the basis for the Arctic eiderdown industry and a historically important food source for some Native American cultures. They also include what is probably the most northerly breeding species of all waterfowl and an icon of Arctic bird life, the long-tailed duck. The sea ducks also include species having some of the most complex and diverse pair-forming postural and acoustic displays of all waterfowl (goldeneyes and bufflehead), and some of the deepest diving species of all waterfowl (scoters and long-tailed duck). Sea ducks are highly prone to population disasters caused by oil spills and other water contaminants and, like other seabirds, are among the first bird groups that are being affected by current global warming trends in polar regions. This book is an effort to summarize succinctly our current knowledge of sea duck biology and to provide a convenient survey of the vast technical literature on the group, with over 900 literature references. It also includes 90,000 words of text (more than 40 percent of which is new), 15 updated range maps, 11 black & white and 20 color photographs, over 30 ink drawings, and nearly 150 sketches. Lastly, the North American sea ducks include the now extinct Labrador duck, the only northern hemisphere waterfowl species to have gone extinct in modern times. I have gratefully reprinted a Labrador duck watercolor by Sir Peter Scott. Considering recent population crashes in other sea ducks, such as the Steller's eider and spectacled eider, it should also offer a sobering reminder of the fragility of our natural world and its inhabitants, including us.
Author: R. L. Wallen
Publisher:
ISBN:
Category : Ducks
Languages : en
Pages : 46
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Book Description
Author: Daniel Esler
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 152
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Book Description
The 1989 Exxon Valdez oil spill was a major perturbation of nearshore habitats of Prince William Sound, a wintering area for harlequin ducks (Histrionicus histrionicus). This research was designed to evaluate harlequin duck population recovery from the oil spill from 1995 to 1998, using a demographic approach to assess both the "product" of population changes (e.g., density differences; Chapter 4) and the demographic "processes" affecting population dynamics (e.g., survival; Chapter 3). Wintering aggregations of harlequin ducks are core population units from a population structure perspective and are largely demographically independent, due to high rates of winter site fidelity, pair formation during winter, and evidence that juveniles follow hens to wintering areas. Therefore, evaluation of population-level effects of the oil spill is appropriately directed at these wintering aggregations. We selected adult female survival as a primary demographic attribute to measure, as population dynamics of animals with life history characteristics like harlequin ducks are particularly sensitive to variation in adult female survival rates. Also, we speculated that oil spill effects during winter would be manifested as survival reductions. We found that winter densities of harlequin ducks were lower on oiled study areas than unoiled areas, after accounting for effects of habitat (Chapter 4), indicating that population recovery had not occurred. Also, we determined that adult female survival was lower on oiled areas than unoiled areas (Chapter 3), and speculated that this was related to documented oil exposure of harlequin duck populations in oiled areas coincident with our study. We also confirmed that our survival estimates were not biased by assumptions about effects of radio transmitters or fate of missing radios (Chapter 2). In Chapter 5, we reviewed all data relevant to harlequin duck recovery from the oil spill, including our demographic data, and concluded that population recovery had not occurred by 1998, deleterious effects persisted, and continued oil exposure likely was the primary constraint to full recovery. Although populations of many species may have recovered quickly from the Exxon Valdez spill, characteristics of harlequin ducks make their winter populations particularly susceptible, including their habitat associations, diet, life history. and energetics
Author: Jean-Pierre L. Savard
Publisher: CRC Press
ISBN: 1482248980
Category : Nature
Languages : en
Pages : 604
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Book Description
The past decade has seen a huge increase in the interest and attention directed toward sea ducks, the Mergini tribe. This has been inspired, in large part, by the conservation concerns associated with numerical declines in several sea duck species and populations, as well as a growing appreciation for their interesting ecological attributes. Reflec
Author: Guy Baldassarre
Publisher: JHU Press
ISBN: 1421408082
Category : Science
Languages : en
Pages : 1183
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Book Description
The best-selling and authoritative reference book on waterfowl has been fully revised and updated by one of the world’s most respected waterfowl biologists. Honorable Mention for the PROSE Award for Excellence, Multivolume/Science of the Association of American Publishers Ducks, Geese, and Swans of North America has been hailed as a classic since the first edition was published in 1942. A must-have for professional biologists, birders, waterfowl hunters, decoy collectors, and wildlife managers, this fully revised and updated edition provides definitive information on the continent's forty-six species. Maps of both winter and breeding ranges are presented with stunning images by top waterfowl photographers and the acclaimed original artwork of Robert W. (Bob) Hines. Originally authored by F. H. Kortright and later revised by Frank Bellrose, this latest edition, which has been meticulously updated by renowned waterfowl biologist Guy Baldassarre, continues the legacy of esteemed authors. Each species account contains in-depth sections on: • identification • distribution • migration behavior • habitat • population status • breeding biology • rearing of young • recruitment and survival • food habits and feeding ecology • molts and plumages • conservation and management To facilitate identification, the species accounts also include detailed illustrations of wings. An appendix contains comparative illustrations of ducklings, goslings, and cygnets. This edition of Ducks, Geese, and Swans consists of two volumes, printed in full color, and packaged in a slipcase, along with a CD containing references and additional maps.
