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Author: Samuel Merrick Patten
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 24
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Author: Samuel Merrick Patten
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 24
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Author: David W. Crowley
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 128
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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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Author: Kenneth A. Dzinbal
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 178
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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: Daniel Esler
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 152
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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: Charles F. Thompson
Publisher: Springer Science & Business Media
ISBN: 1441964215
Category : Science
Languages : en
Pages : 201
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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: E. Frances Cassirer
Publisher:
ISBN:
Category : Ducks
Languages : en
Pages : 118
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Author: Paul Johnsgard
Publisher: Lulu.com
ISBN: 1609621069
Category : Nature
Languages : en
Pages : 258
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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: Frances Cassirer
Publisher:
ISBN:
Category : Harlequin duck
Languages : en
Pages : 106
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Harlequin ducks (Histrionicus histrionicus) are sea ducks that migrate to mountain streams to breed. The species is classified as a U.S. forest Service sensitive species in the Northern, Rocky Mountain, and Pacific Northwest Regions, a state sensitive species in Oregon, a priority habitat species in Washington, and a species of special concern in Idaho, Montana, and Wyoming. Harlequin ducks are also classified as migratory waterfowl covered under general waterfowl or sea duck regulations throughout their range. This Conservation Assessment and Strategy addresses the status and conservation of harlequin ducks in the Rocky Mountains of Idaho, Montana, and Wyoming. The Conservation Assessment summarizes available information on the ecology and population status of the harlequin duck in Idaho, Montana, and Wyoming, and identifies potential threats to the species' viability in this region. The Conservation Strategy identifies management actions and information needed in order to maintain viable populations and protect and maintain critical habitats to ensure that listing is not warranted, in accordance with the Endangered Species Act (ESA) of 1973, as amended. The Conservation Assessment is based on inventory, monitoring, and research data collected in the U.S. Rocky Mountains since 1974. Approximately 300 pairs of harlequin ducks are estimated to breed in 57 breeding or probable breeding occurrences in the U.S. Rocky Mountains. A breeding occurrence is considered a single "breeding area", but may contain portions of several streams not separated by more than 10 km of unsuitable habitat, or 20 km of unoccupied, suitable habitat. Data gathered from marked individuals indicates a high degree of fidelity to these breeding occurrences. The harlequin duck breeding occurrences identified in the U.S. Rocky Mountains are comprised of reaches on 128 streams. Over 90% of the harlequin duck breeding occurrences in the U.S. Rocky Mountains occur on federal lands, primarily managed by the U.S. Forest Service and National Park Service. However, approximately 25% of these do cross some privately-owned land. The remaining 7% (4 breeding occurrences) are located predominately on state and privately-owned land. Not all Rocky Mountain breeding occurrences have been located. Potential breeding habitat is identified as 2nd-order or larger streams containing reaches with a average gradient of 1% - 7%, riffle habitat, clear water, gravel to boulder-sized substrate, and forested bank vegetation. Additional characteristics that may increase likelihood of use by harlequin ducks include: proximity to occupied habitat, overhanging bank vegetation, woody debris, loafing sites, absence of human activity, and inaccessibility. Potential threats to harlequin ducks in the U.S. Rocky Mountains include activities that affect riparian habitats, water yield, water quality, and increase disturbance during the breeding season. Habitat conditions in migratory and coastal areas are also critical to conservation of harlequin ducks. Harlequin ducks breeding in the Rocky Mountains have been located off the coasts of Oregon, Washington, and British Columbia. Harvest in coastal areas, while apparently low, could also potentially affect harlequin ducks in the Rocky Mountains. The Conservation Strategy emphasizes and adaptive approach for maintaining riparian and instream harlequin duck habitat. Guidelines are designed to maintain habitat quality by avoiding degradation form timber harvest, road construction and maintenance, mining, livestock grazing, water developments, and recreation. Guidelines include establishing stream buffers, maintaining instream flows and water quality, and reducing or not increasing human disturbance. Inventory and monitoring protocols are included for assessing the U.S. Rocky Mountain harlequin duck population size and trend and for individual project inventory and monitoring. Finally, areas where additional information is needed regarding basic ecology and management and methods to increase knowledge of management personnel and the public about harlequin duck and their conservation are identified.
Author:
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ISBN:
Category :
Languages : en
Pages : 548
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