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Johnsgard, Paul A. - One of the best experts on this subject based on the ideXlab platform.
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Waterfowl of North America: Waterfowl Distributions and Migrations in North America
DigitalCommons@University of Nebraska - Lincoln, 2010Co-Authors: Johnsgard, Paul A.Abstract:The species of waterfowl breeding in North America have distribution patterns that collectively reflect the past geologic and ecological histories of this continent. In general, our waterfowl species may be grouped into those that are limited (endemic) to North America, those that are shared between North and South America, and those that are shared with Europe and/or Asia. Of the forty-four species known to breed in continental North America, the resulting grouping of breeding distributions is as follows: Limited to North America: Snow goose (also on Greenland and Wrangel Island) , Ross goose, Canada goose (also on Greenland), wood duck, American wigeon, black duck, blue-winged teal, redhead, Canvasback, ringnecked duck, lesser scaup, Labrador duck (extinct), surf scoter, bufflehead, hooded merganser. Shared with Eurasia: Trumpeter swan (whooper swan), whistling swan (Bewick swan), white-fronted goose, brant goose, gadwall, green-winged teal, mallard, pintail, shoveler, greater scaup, common eider, king eider, harlequin duck, oldsquaw, black scoter, white-winged scoter, common goldeneye, red-breasted merganser, common merganser. Shared with South America: Fulvous whistling duck, black-bellied whistling duck, muscovy duck, cinnamon teal, masked duck, ruddy duck. Shared with Asia only: Emperor goose, spectacled eider, Steller eider (rarely to Norway). Shared with Europe only: Barrow goldeneye (Iceland and Greenland). Native to Eurasia, introduced into North America: Mute swan. It is thus clear that the strongest zoogeographic affinities of our waterfowl are with Europe and Asia, since twenty-three out of the forty-four native North American species have .populations shared with one or both of these areas. Only six species are shared with South America, and, of these, the fulvous whistling duck has a more general tropical distribution that includes Africa and southern Asia. Consequently, it would appear that South America has played only a minor role in providing waterfowl stock for North America, and vice versa. Certainly the great number of waterfowl species shared between the North American and Eurasian landmasses can be largely attributed to Pleistocene and post-Pleistocene history. Ploeger (1968) analyzed the distributions of eighteen species of arctic-breeding Anatidae and concluded that both their present distributions and their described geographic variations could be at· tributed to the physical-geographical situation existing in the Northern Hemisphere during Late Glacial times. Only a minority (38 percent) of these species exhibit noticeable geographic variation, and most of the eighteen have breeding ranges that include both North America and Eurasia. The exceptions are three Eurasian geese (red-breasted, bean, and lesser white-fronted geese), three North American geese (Canada, Ross, and snow geese), and the North Atlantic barnacle goose. It is of interest that these are all geese, a group noted for their strongly traditional wintering and breeding grounds, as opposed to the less tradition-bound ducks
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Waterfowl of North America: Color photographs (following page 50)
DigitalCommons@University of Nebraska - Lincoln, 2010Co-Authors: Johnsgard, Paul A.Abstract:Trumpeter Swan, Adult (drinking) Lesser Snow Goose (Blue Phase), Adult and young Lesser Canada Goose, Adults Atlantic Brant, Adult Barnacle Goose, Adults Wood Duck, Adult Male American Wigeon, Pair Gadwall, Pair Green-winged Teal, Pair Mexican Mallard, Adult Male Florida Mallard, Pair Northern Pintail, Pair Blue-winged Teal, Pair Cinnamon Teal, Pair Shoveler, Pair Canvasback, Pair Redhead, Pair Ring-necked Duck, Pair Greater Scaup, Pair King Eider, Pair Steller Eider, Adults Harlequin Duck,Male Surf Scoter, Male Bufflehead, Pair Barrow Goldeneye, Pair Common Goldeneye, Pair Hooded Merganser, Displaying Male Red-breasted Merganser, Male Common Merganser, Pair Ruddy Duck, Mal
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Waterfowl of North America: Black & white photographs (following page 338)
DigitalCommons@University of Nebraska - Lincoln, 2010Co-Authors: Johnsgard, Paul A.Abstract:Gadwall, Pair Gadwall, Adult male Baikal Teal, Pair American Green-winged Teal, Pair Baikal Teal, Adult male American Green-winged Teal, Adult male Common Mallard, Adult male Common Mallard, Brooding female Mexican Mallard, Pair Florida Mallard, Pair Northern Pintail, Adult male Bahama Pintail, Adult male Garganey, Adult male Garganey, Pair Blue-winged Teal, Pair Cinnamon Teal, Pair Northern Shoveler, Adult male Northern Shoveler, Pair Canvasback, Adult female Canvasback, Pair Redhead, Adult male Redhead, Adult female Ring-necked Duck, Pair Ring-necked Duck, Pair Tufted Duck, Pair Greater Scaup, Pair Greater Scaup, Adult male Lesser Scaup, Pair American Common Eider, Adult males American Common Eider, Group of adults King Eider, Adult male King Eider, Adult femal
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Ducks, Geese, and Swans of the World: Tribe Aythyini (Pochards)
DigitalCommons@University of Nebraska - Lincoln, 2010Co-Authors: Johnsgard, Paul A.Abstract:Pink-headed Duck ● Red-crested Pochard ● Southern Pochard ● Rosybill ● Canvasback ● Eurasian Pochard ● Redhead ● Ring-necked Duck ● Australasian White-eye ● Siberian White-eye (Baer Pochard) ● Ferruginous White-eye ● Madagascan White-eye ● Tufted Duck ● New Zealand Scaup ● Greater Scaup ● Lesser Scaup This tribe of primarily fresh-water diving ducks contains 16 species that collectively may be called pochards. The tribe has a nearly worldwide distribution, but only a few of its species have ranges that extend beyond a single continent. In addition to 15 species that are very similar in body proportions and diving adaptations, the apparently extinct pink-headed duck has anatomical characteristics that approach those of the pochards and it clearly should be included in this tribe. All of the typical pochards are adept at diving and possess large feet, with long outer toes and strongly lobed hind toes. Their legs are placed quite far apart and are situated farther back on the body than in other ducks, making the birds relatively awkward on land but improving their diving efficiency. They also have a heavier body size to wing-surface ratio, forcing them to run for some distance over the water when taking flight, in contrast to the springing takeoff of dabbling ducks. Although sexual dimorphism occurs to some extent in all species, male plumage patterns are generally not especially complex, and the wing speculum patterns are either lacking or limited to gray or white stripes. The females of pochards are usually rather uniformly brownish, and lack the very distinct patterning of female dabbling ducks. Nesting is usually done on land near water or, more commonly, in beds of emergent vegetation. The downy young tend to be weakly or obscurely patterned with shades of yellow and dark brown
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\u3ci\u3eBirds of the Rocky Mountains\u3c/i\u3e—Species Accounts, pages 76–109: Swans, Geese and Ducks
DigitalCommons@University of Nebraska - Lincoln, 2009Co-Authors: Johnsgard, Paul A.Abstract:Tundra (Whistling) Swan (Cygnus columbianus) Trumpeter Swan (Cygnus buccinator) Greater White-fronted Goose (Anser albifrons) Snow Goose (Chen caerulescens) Ross\u27 Goose (Chen rossii) Canada Goose (Branta canadensis) Wood Duck (Aix sponsa) Green-winged Teal (Anas crecca) American Black Duck (Anas rubripes) Mallard (Anas platyrhynchos) Northern Pintail (Anas acuta) Blue-winged Teal (Anas discors) Cinnamon Teal (Anas cyanoptera) Northern Shoveler (Anas clypeata) Gadwall (Anas strepera) Eurasian Wigeon (Anas penelope) American Wigeon (Anas americana) Canvasback (Aythya valisineria) Redhead (Aythya americana) Ring-necked Duck (Aythya collaris) Greater Scaup (Aythya marila) Lesser Scaup (Aythya affinis) Harlequin Duck (Histrionicus histrionicus) Oldsquaw (Clangula hyemalis) Black Scoter (Melanitta nigra) Surf Scoter (Melanitta perspicillata) White-winged Scoter (Melanitta fusca) Common Goldeneye (Bucephala clangula) Barrow\u27s Goldeneye (Bucephala islandica) Bufflehead (Bucephala albeola) Hooded Merganser (Lophodytes cucullatus) Common Merganser (Mergus merganser) Red-breasted Merganser (Mergus serrator) Ruddy Duck (Oxyura jamaicensis
Michael D Sorenson - One of the best experts on this subject based on the ideXlab platform.
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Effects of intra- and interspecific brood parasitism on a precocial host, the Canvasback,
2015Co-Authors: Aythya Valisineria, Michael D SorensonAbstract:Canvasback ducks (Aythya vaUimrria) suffer both intra- and interspecific brood parasitism. During 3 years in Manitoba, 80 % of Canvasback nests (n « = 179 nests with completed dutches) were parasitized by redheads (A. amtricana), other Canvasbacks, or both, with an average of 4.7 parasitic eggs per parasitized nest Parasitism had significant negative effects on the reproductive success of nesting Canvasbacks, although the proximate mechanisms involved differed from those operating in altricial species. Accidental displacement of eggs when parasitic females forced their way onto host nests was the principal negative effect of parasitism, reducing the number of host eggs that were incubated and ultimately hatched. Parasitism by redheads was relatively more costly to Canvasbacks than was intraspetific parasitism, with approximately 0.31 and 0.17 host eggs displaced per parasitic redhead and Canvasback egg laid, respectively. No additional negative effects of parasitism on the hatchability of host eggs occurred subsequent to parasitic laying. Posthatch survival of Canvasback ducklings was lower in broods from parasitized nests but was unrelated to the presence or absence of redhead ducklings. Canvasback hosts resisted intrusions by parasitic females but showed no evidence of discrimination against parasitic eggs or ducklings. Because most costs of parasitism in this system are inflicted at the time of parasitic laying, subsequent rejection of parasitic eggs or ducklings is probably of little benefit to Canvasback hosts, while the evolution of behavior that might prevent parasitic laying in die first place, such as more vigorous nest defense, may be constrained by its high costs. Key words: Aythya americana, Aythya vahsmeria, Canvasback, interspecific brood parasitism, intraspedfic brood parasitism, redhead. [Bthav Ecol 8:153~161 (1997)
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sexual imprinting misguides species recognition in a facultative interspecific brood parasite
Proceedings of The Royal Society B: Biological Sciences, 2010Co-Authors: Mark E. Hauber, Michael D Sorenson, Scott R DerricksonAbstract:Sexual reproduction relies on the recognition of conspecifics for breeding. Most experiments in birds have implicated a critical role for early social learning in directing subsequent courtship behaviours and mating decisions. This classical view of avian sexual imprinting is challenged, however, by studies of megapodes and obligate brood parasites, species in which reliable recognition is achieved despite the lack of early experience with conspecifics. By rearing males with either conspecific or heterospecific brood mates, we experimentally tested the effect of early social experience on the association preferences and courtship behaviours of two sympatrically breeding ducks. We predicted that redheads (Aythya americana), which are facultative interspecific brood parasites, would show a diminished effect of early social environment on subsequent courtship preferences when compared with their host and congener, the Canvasback (Aythya valisineria). Contrary to expectations, cross-fostered males of both species courted heterospecific females and preferred them in spatial association tests, whereas control males courted and associated with conspecific females. These results imply that ontogenetic constraints on species recognition may be a general impediment to the initial evolution of interspecific brood parasitism in birds. Under more natural conditions, a variety of mechanisms may mitigate or counteract the effects of early imprinting for redheads reared in Canvasback broods.
James R. Lovvorn - One of the best experts on this subject based on the ideXlab platform.
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Food dispersion and foraging energetics : A mechanistic synthesis for field studies of avian benthivores
Ecology, 1995Co-Authors: James R. Lovvorn, Michael P. GillinghamAbstract:Much effort has focused on modeling and measuring the energy costs of free existence and the foraging strategies of animals. However, few studies have quantitatively linked these approaches to the patch structure of foods in the field. We developed an individual-based model that relates field measurements of the dispersion of benthic foods to search costs and foraging profitability of diving ducks. On Lake Mattamuskeet, North Carolina, Canvasback ducks (Aythya valisineria) eat only the belowground winter buds of the submerged plant Vallisneria americana. We measured and modeled the patch structure of winter buds at the level of potential foraging loci, defined as contiguous circles 1 m in diameter. In the field and in the model, Canvasbacks make repeated vertical dives in such loci, foraging in the sediments by touch, before surface-swimming to another locus. We quantified first-order patchiness by fitting a negative binomial distribution to core samples taken at 50-m intervals along transects, to yield the frequencies of loci with different bud densities. Second-order patchiness was measured by taking cores at 1-m increments radiating from each sampling point, and regressing bud density at each sampling point on densities at these increments. No significant correlations were found, indicating that Canvasbacks could not predict food densities based on densities in nearby foraging loci. For the model, we generated food grids from the negative binomial distributions of core samples. Energy costs of diving were calculated by applying aerobic efficiencies (mechanical power output + aerobic power input) to biomechanical models. Unlike respirometry alone, this method accounts for effects on dive costs of varying water depth and dive duration. We used measurements of Canvasback intake rates at different bud densities to calculate profitability (energy intake minus expenditure) for each dive. Multivariate uncertainty analyses (Latin hypercube) indicated that profitability for Canvasbacks foraging on Vallisneria buds is determined mainly by food-item size and locomotor costs of descent. Bud metabolizable energy, water temperature, bud dispersion, and search and handling time coefficients of the functional response for intake rate have relatively minor influence. Individual-parameter perturbations indicated that to maintain the same foraging benefits, the total area of Vallisneria habitat would have to increase by 1.4-fold if dry mass per bud decreased from 0.10 to 0.03 g, and by 2.1-fold if water depth increased from 0.5 to 2 m. Our method allows study of interactions between patch structure and foraging energetics without detailed spatial mapping of foods, which is not feasible at appropriate scales for highly mobile benthivores. The model yields estimates of energy balance, contaminant intake, and amount and quality of foraging habitat required to sustain diving duck populations under varying environmental conditions. More accurate prediction of giving-up times and giving-up food densities will require better understanding of the time scale over which ducks balance their energy budgets.
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nutrient reserves probability of cold spells and the question of reserve regulation in wintering Canvasbacks
Journal of Animal Ecology, 1994Co-Authors: James R. LovvornAbstract:Interpreting body mass and composition of wintering birds is often confounded by the inability to discriminate endogenous regulation of reserves from effects of proximate weather and food conditions. Endogenous regulation is thought to act through genetically controlled set-points that change throughout the year, due to evolutionary adaptation to long-term probabilities of needing reserves at different times. For Canvasbacks (Aythya valisineria) wintering in upper Chesapeake Bay, coastal North Carolina, and Louisiana, I calculated over many years the probability of cold spells when Canvasbacks likely depend on reserves. I then analysed whether the timing of such cold spells is predictable enough to form the basis for monthly schedules of endogenous reserve regulation in free-ranging Canvasbacks
Carl E Korschgen - One of the best experts on this subject based on the ideXlab platform.
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survival of radiomarked Canvasback ducklings in northwestern minnesota
Journal of Wildlife Management, 1996Co-Authors: Carl E Korschgen, Kevin P Kenow, Douglas H. Johnson, W L Green, Michael D Samuel, Louis SileoAbstract:Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for Canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of Canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were radiomarked and released in 52 broods. Another 141 ducklings were radiomarked at ≥ 4 weeks of age. Survival was estimated with the Kaplan-Meier nonparametric estimator and the Weibull parametric model. Most mortalities occurred within 10 days after hatch. Total brood loss occurred in 18 (35%) of 52 broods released. The primary sources of mortality were predation, principally by mink (Mustela vison), and exposure to precipitation and cold temperature. For combined years, females had lower survival than males (P = 0.03). If the disparate survival between sexes of Canvasbacks observed in this study is representative of Canvasbacks in their breeding range, this phenomenon contributes to reduced reproductive potential and the male-biased sex ratio of the species.
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Canvasback mortality from illegal hunting on the upper mississippi river
Wildlife Society Bulletin, 1996Co-Authors: Carl E Korschgen, Kevin P Kenow, James M Nissen, John F WetzelAbstract:To quantify the consequences of local hunting on illegal kill of Canvasbacks (Aythya valisineria), we studied the behavior of hunters on a 646-ha area open to duck hunting (closed to Canvasback hunting) on Lake Onalaska, Navigation Pool 7, Wisconsin, during the 1 991 and 1 992 waterfowl hunting seasons. Law enforcement officers observed 258 hunting parties for 419 hours. Of 94 hunting parties encountering Canvasbacks, 41 (44%/O) shot at the ducks on 56 occasions, or 27% of 207 encounters observed. Based on a ratio estimator, there were 790 (95% Cl = 376) attempts to shoot at Canvasbacks on the Lake Onalaska study area during 1991 and 837 (95O/% Cl = 390) during 1 992. Mortality of Canvasbacks, excluding crippling loss, was estimated to be 128 during 1991 and 166 during 1 992. Thus, total Canvasback losses may be higher than currently estimated on a flyway or national basis. This estimating technique offers a promising method for enumerating hunter take of protected and legal species.
John F Wetzel - One of the best experts on this subject based on the ideXlab platform.
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Canvasback mortality from illegal hunting on the upper mississippi river
Wildlife Society Bulletin, 1996Co-Authors: Carl E Korschgen, Kevin P Kenow, James M Nissen, John F WetzelAbstract:To quantify the consequences of local hunting on illegal kill of Canvasbacks (Aythya valisineria), we studied the behavior of hunters on a 646-ha area open to duck hunting (closed to Canvasback hunting) on Lake Onalaska, Navigation Pool 7, Wisconsin, during the 1 991 and 1 992 waterfowl hunting seasons. Law enforcement officers observed 258 hunting parties for 419 hours. Of 94 hunting parties encountering Canvasbacks, 41 (44%/O) shot at the ducks on 56 occasions, or 27% of 207 encounters observed. Based on a ratio estimator, there were 790 (95% Cl = 376) attempts to shoot at Canvasbacks on the Lake Onalaska study area during 1991 and 837 (95O/% Cl = 390) during 1 992. Mortality of Canvasbacks, excluding crippling loss, was estimated to be 128 during 1991 and 166 during 1 992. Thus, total Canvasback losses may be higher than currently estimated on a flyway or national basis. This estimating technique offers a promising method for enumerating hunter take of protected and legal species.