Isolation and characterization of 22 polymorphic microsatellite loci for the Barrow's goldeneye (Bucephala islandica)

We describe primers and polymerase chain reaction conditions to amplify 22 microsatellite loci from the Barrow's goldeneye (Bucephala islandica). The primers were tested on 27 individuals from a population breeding in British Columbia, Canada. The developed primer pairs yielded an average of 6.11 alleles per locus (range 2-12), an average observed heterozygosity of 0.70 (range 0.07-0.96) and a polymorphic information content of 0.07-0.88.     

4种生态类群中10种鸟消化系统的形态学比较

本文从生态类群角度,对游禽(绿头鸭、秋沙鸭、鹊鸭、斑嘴鸭)、鸣禽(红尾伯劳、白头鹀、白眉鹀)、猛禽(雕鸮、金雕)和涉禽(苍鹭)这4种生态类群中10种鸟的消化系统形态结构进行了比较分析.研究获得各项基础数据,通过比较表明,4种生态类群10种鸟类消化系统形态多处存在明显差异.对于不同生态类群的鸟类来说,食性、食物的质量及活动特点等是影响消化系统形态的重要因素.     

Vacuolar myelinopathy in waterfowl from a North Carolina impoundment

Vacuolar myelinopathy was confirmed by light and electron microscopic examination of mallards (Anas platyrhynchos), ring-necked ducks (Aythya collaris), and buffleheads (Bucephala albeola) collected during an epizootic at Lake Surf in central North Carolina (USA) between November 1998 and February 1999. Clinical signs of affected birds were consistent with central nervous system impairment of motor function (incoordination, abnormal movement and posture, weakness, paralysis). This is the first report of this disease in wild waterfowl (Anseriformes).     

Profilicollis botulus (Van Cleave, 1916) from diving ducks and shore crabs of British Columbia

Adults of Profilicollis botulus were found in 6 species of diving ducks in British Columbia including 3 new hosts: common goldeneye, Bucephala clangula (L.); Barrow's goldeneye, B. islandica (Gmelin); and greater scaup, Aythya marila (L.). The identification of the species was verified by the examination of co-types and specimens from eider ducks, Somateria mollissima (L.), from Scotland and oldsquaw, Clangula hyemalis (L.), from New Brunswick. Cystacanths from the hairy shore crab, Hemigrapsus oregonensis (Dana), were similar in morphology to those from Carcinus maenas (L.) from Scotland.     

The Body Size-Dependent Diet Composition of North American Sea Ducks in Winter

Daily food requirements scale with body mass and activity in animals. While small species of birds have higher mass-specific field metabolic rates than larger species, larger species have higher absolute energy costs. Under energy balance, we thus expect the small species to have a higher energy value diet. Also the weight and time constraints for flighted and diurnal foragers should set a maximum to the amount of prey items taken in one meal and to the daily number of meals, respectively. Further, avoidance of competition causes the species to reduce the amount of shared prey in their diet. Some diet segregation is therefore to be expected between species. We tested these hypotheses and investigated the role of body mass in the diet composition of 12 sea duck species (Somateria mollissima, Somateria spectabilis, Somateria fischeri, Polysticta stelleri, Bucephala clangula, Bucephala islandica, Bucephala albeola, Melanitta nigra, Melanitta perspicillata, Melanitta deglandi, Histrionicus histrionicus and Clangula hyemalis) wintering in North America. This study was based on a literature survey with special emphasis given to the diet data from the former US Bureau of Biological Survey. The data supported our hypothesis that the energy value of winter diet of sea ducks scales negatively with body mass. Diet diversity also scaled negatively with body mass. Our results suggest the existence of a minimum for the energy value of avian diets.     

Moulting diving ducks and their food supply

Numbers of moulting diving ducks at Myvatn, north Iceland, were monitored over a period of 25 years; aquatic insects (Chironomidae and Simuliidae), a major food resource, were monitored with window traps for 23 years. The response of the duck populations to changes in the food situation during the moulting period varied between species. Histrionicus histrionicus and Melanitta nigra invariably go to the sea to moult. Three species (Aythya fuligula, Clangula hyemalis and Mergus serrator) have shown long term variation in moult migration habits. Aythya marila and Bucephala islandica stay for moulting, their numbers supplemented by birds from elsewhere. A. marila is a generalist feeder and therefore at low risk of starving, the strategy of Bucephala islandica is to move within the water system where the food situation tends to alternate between the lake and the river. Numbers of Bucephala islandica males moulting on Lake Myvatn were strongly and positively correlated with chironomid numbers and those moulting on the river Laxá with Simulium vittatum, the main food resource there. We did not find convincing evidence that numbers of moulting A. marila and C. hyemalis responded to variation in the food supply during the study period. This applied also to A. fuligula in the South Basin of Myvatn, but numbers in the North Basin were positively associated with chironomid numbers. M. serrator moulting on Myvatn showed negative correlations with the chironomids, perhaps reflecting a negative association between chironomids and its main food, Gasterosteus aculeatus. Apart from safety considerations for a flightless bird, the choice of a moulting site is apparently influenced by the local food conditions on one hand and by the opportunities and risks involved in migrating to distant moulting sites with an unknown food situation on the other hand.     

A blood survey of elements, viral antibodies, and hemoparasites in wintering Harlequin Ducks (Histrionicus histrionicus) and Barrow's Goldeneyes (Bucephala islandica)

Twenty-eight Harlequin Ducks (Histrionicus histrionicus) and 26 Barrow's Goldeneyes (Bucephala islandica) were captured in Prince William Sound, Alaska, between 1 and 15 March 2005. Blood was collected for quantification of element concentrations, prevalence of antibodies to several viruses, and hemoparasite prevalence and identification. Although we found selenium concentrations that have been associated with selenosis in some birds (>or=2.0 ppm ww), our findings contribute to a growing literature describing relatively high selenium in apparently healthy birds in marine environments. Avian influenza virus antibodies were detected in the plasma of 28% of the ducks. No antibodies against adenovirus, reovirus, or paramyxovirus 1 were detected. Several hemo-parasite species were identified in 7% of ducks. Our findings are similar to those in other free-living marine waterfowl and do not indicate unusual concerns for the health of these species in this area in late winter.     

Abundance and feeding of wintering and migrating aquatic birds in two sampling areas of Lake Balaton in 1983–1985

The investigation was carried out at two sampling areas in Lake Balaton (surface area 600 km²), of which one was hypertrophic and the other was mesotrophic. Species diversity was higher in the hypertrophic area, primarily due to a higher number of Anatid species. Contents of crops, gizzards, and intestines were analysed in 321 of the 361 birds collected. Diet was similar in certain species (Aythya fuligula, A. f. ferina, Anas querquedula) despite differences in the trophic state of their habitats. However, in other species (Anas p. platyrhyncha, Aythya nyroca, Bucephala c. clangula), percentage distribution of food items more or less reflected the food resources of the two areas in the digestive tracts. I concluded that the former species are highly selective in their feeding.     

Efficiency Gain from Auxiliary Data Requiring Additional Nuisance Parameters

In a mark-recapture study of an animal population, live-recapture information may be supplemented by resightings from marked animals obtained throughout the period of the study and the two types of data analyzed simultaneously. The resighting data can only contribute to estimates of survival probability if they are jointly modeled with the live-recapture data and require the inclusion of additional nuisance parameters. We show that, under quite general conditions, estimates of the original parameters are estimated with the same, or improved, precision despite the inclusion of the nuisance parameters. Banding data from female goldeneye ducks (Bucephala clangula) are used as an illustration.     

Redistribution of extracellular water and sodium may contribute to saline tolerance in wild ducks

The compartmentalization of body fluids was measured in three species of ducks that differ in saline tolerance. Half of the birds of each species drank freshwater, while the other half drank saline (300 mM NaCl). Among ducks that drank freshwater, total body water (TBW) was similar among all species, but Barrow's goldeneyes (Bucephala islandica), the most marine species, had larger extracellular fluid volume (ECFV) than freshwater mallards (Anas platyrhynchos) or estuarine canvasbacks (Aythya valisineria). When acclimated to saline, only goldeneyes shifted extracellular water and Na+ into the intracellular compartment. ECFV was correlated with plasma aldosterone concentration in goldeneyes, but not in canvasbacks (aldosterone was not measured in mallards). Data summarized from the literature showed that TBW does not differ among terrestrial, freshwater, or marine species, but marine species have a larger part of their TBW in the extracellular compartment. Saline induced movement of extracellular water and Na+ into the cells only in goldeneyes. ECFV and redistribution of extracellular water and Na+ into the cells may be important components in saline tolerance of marine birds.     

Identification of parasitized nests by using egg morphology in the Common Goldeneye: an alternative to blood sampling

We used data from three Common Goldeneye Bucephala clangula populations in Finland to study if the variation between females in egg morphology, as measured using a method developed by Eadie (1989), can be used to identify parasitized clutches. Eadie's method is based on z-score standardized measures of length, width, and weight of eggs. Using these measures, Euclidean distance for each pair of eggs within a clutch was calculated. Euclidean distance between the two most dissimilar eggs (maximum Euclidean distance, MED) was used as the criterion to identify parasitized clutches. Test clutches of 3 eggs that included one egg from each of three different females had a higher MED (2.80) than 3-egg clutches that included eggs from one female only (2.05), proving that there is statistically significant variation in egg morphology between females. Test clutches that included three eggs from each of three different females (9 eggs in all) had a mean MED of 4.51. The mean MED of naturally parasitized clutches (4.83) was higher than that of nonparasitized clutches (2.12). Further analyses suggested that MED>3.0 can be used as a conservative and reliable criterion to identify parasitized clutches. Our results confirm that Eadie's method is reliable enough to identify parasitized clutches in Common Goldeneyes.     

Breeding success of ducks in relation to different habitat factors

Breeding success of four duck species, Teal Anas crecca , Mallard Anas platyrhynchos , Wigeon Anas penelope and Goldeneye Bucephala clangula , was studied in a boreal watershed in southern Finland during 1988–1991 in relation to habitat type (based on vegetation development) and food abundance. Of the three common breeders, breeding success (broods/ pair) was highest in Teal (1.7) and lower in Mallard (1.4) and Goldeneye (1.2). Over the years, Goldeneye brood densities were less variable than were pair densities, so breeding success varied more among years that did that of Mallard or Teal. In Teal, the yearly numbers of pairs and broods fluctuated together, whereas in Mallard neither varied appreciably. Breeding success by Goldeneye was higher where nektonic invertebrates were more abundant, whereas breeding success of the dabbling ducks had very few significant correlations with environmental factors.     

Public information and conspecific nest parasitism in goldeneyes: targeting safe nests by parasites

Conspecific nest parasitism (CNP) is a widespread alternativereproductive tactic in birds. Several hypotheses have been putforward to explain the evolution and occurrence of CNP, butno generally applicable hypothesis exists. Recent experimentalresults from the common goldeneye (Bucephala clangula), a cavity-nestingduck, have revealed that parasitic females preferentially layeggs in safe nest-sites, implying that nest predation risk isan important ecological determinant of CNP. The present studyfocuses on the mechanisms by which parasites identify safe nest-sites.Predation risk of a given nest-site was predictable betweensuccessive breeding seasons. At the end of the nesting season,females prospected active nest-sites more frequently than nest-sitesthat did not have a nest in the current season. Nest-sites thathad been prospected more frequently by females in year t hada higher probability to be parasitized in year t + 1. The resultssuggest that the use of public information, derived throughnest-site prospecting, enabled parasites to target safe nests.These findings provide a new and potentially generally applicableperspective to understand the evolution and occurrence of CNP.     

Relatedness and spatial proximity as determinants of host–parasite interactions in the brood parasitic Barrow's goldeneye (Bucephala islandica)

Recent studies, which have found evidence for kin-biased egg donation, have sparked interest in re-assessing the parasitic nature of conspecific brood parasitism (CBP). Since host–parasite kinship is essential for mutual benefits to arise from CBP, we explored the role of relatedness in determining the behaviour of conspecific nest parasites and their hosts in nesting female Barrow's goldeneyes ( Bucephala islandica ), a duck in which CBP is common. The results revealed that the amount of parasitism increased with host–parasite relatedness, the effect of which was independent of geographical proximity of host and parasite nests. Proximity per se was also positively associated with the amount of parasitism. Furthermore, while hosts appeared to reduce their clutch size as a response to the presence of parasitic eggs, the magnitude of host clutch reduction also tended to increase with increasing relatedness to the parasite. Hence, our results indicate that both relatedness and spatial proximity are important determinants of CBP, and that host clutch reduction may be an adaptation to nest parasitism, modulated by host–parasite relatedness. Taken together, the results provide a demonstration that relatedness influences host and parasite behaviour in Barrow's goldeneyes, resulting in kin-biased egg donation.     

Habitat selection and survival of Common Goldeneye (Bucephala clangula) broods — preliminary results

Factors affecting habitat selection and survival of individual Common Goldeneye (Bucephala clangula) broods were studied. Females were marked with radio transmitters and coloured wing tags, and their movements and that of their broods were followed to investigate the pattern of lake use.Broods frequently left hatching lakes and moved varying distances and made overland travels to reach actual brood rearing lakes. Food was more abundant and pH lower in rearing lakes compared with hatching lakes. Rearing lakes also were smaller and more isolated than hatching lakes but did not differ with respect to the structure of shore vegetation.Mortality rate varied considerably between broods. However, total distance moved and the length of overland travel was not associated with increased duckling mortality. Neither was mortality associated with the size, isolation or vegetation structure of the rearing lakes.     

Survival of Barrow's goldeneyes during remigial molt and fall staging

Postbreeding survival of waterfowl is rarely quantified, despite potential for constraints during this stage of the annual cycle that may subsequently affect population dynamics. We estimated survival of radio-marked adult male Barrow's goldeneyes (Bucephala islandica) during remigial molt and fall staging at Cardinal and Leddy Lakes in the Boreal Transition Zone of northwestern Alberta, Canada. Daily survival rate (DSR) was high during remigial molt (DSR = 0.9987, 95% CI: 0.9967–1.0000), corresponding to a 39-day period survival rate (PSR) of 0.95 (95% CI: 0.88–1.00). During fall staging, DSR was markedly lower (DSR = 0.9938, 95% CI: 0.9898–0.9978), corresponding to a PSR of 0.68 (95% CI: 0.53–0.87) over the 62-day period between the end of remigial molt and fall migration. Half of fall staging mortalities observed on Cardinal Lake were directly attributed to hunting. We conclude that remigial molt is a period with high survival in the annual cycle of Barrow's goldeneyes at our study sites. However, in light of low fall staging survival, Barrow's goldeneye harvest management strategies should be carefully evaluated with intent to reduce risk of localized high mortality at significant staging sites in western Canada. © 2013 The Wildlife Society.     

Avian wildlife reservoir of Campylobacter fetus subsp. jejuni, Yersinia spp., and Salmonella spp. in Norway

Cloacal swabs from 540 wild-living birds were cultured for Campylobacter fetus subsp. jejuni, Yersinia spp., and Salmonella spp. The carrier rates detected were as follows: C. fetus subsp. jejuni, 28.4%; Yersinia spp., 1.2%; and Salmonella spp., 0.8%. All birds were apparently healthy when captured. C. fetus subsp. jejuni was isolated from 11 of the 40 bird species examined. Among birds inhabiting the city of Oslo, the highest isolation rate was found in crows (Corvus corone cornix) (89.8%), followed by gulls (Larus spp.) (50.0%) and domestic pigeons (Columba livia domesticus) (4.2%). The gulls and crows scavenge on refuse dumps. High carrier rates were also detected among the following birds from nonurban, coastal areas: puffin (Fratercula arctica) (51.3%), common tern (Sterna hirundo) (5.6%), common gull (Larus canus) (18.9%), black-headed gull (Larus ridibundus) (13.2%), and herring gull (Larus argentatus) (4.2%). The list of species harboring C. fetus subsp. jejuni also includes the Ural owl (Strix uralensis), goldeneye (Bucephala clangula), and reed bunting (Emberiza schoeniclus). The following five Yersinia strains were isolated: Y. kristensenii (two strains), Y. intermedia (two strains), and "Yersinia X2" (one strain). Four strains belonging to the genus Salmonella were isolated from three different species of gulls. These isolates were identified as S. typhimurium, S. indiana, and S. djugu. The results indicate that campylobacters are a normal component of the intestinal flora in several bird species, whereas Salmonella and Yersinia carriers are more sporadic.     

Relatedness and the evolution of conspecific brood parasitism: parameterizing a model with data for a precocial species

Conspecific brood parasitism (CBP) is a common reproductive tactic in several animal taxa, especially in precocial birds. It has been suggested that host-parasite relatedness can facilitate the evolution of CBP. A recent model showed that the existence and accuracy of the kin recognition system is crucial for this to occur. I used field data to parameterize the model for the common goldeneye, Bucephala clangula, a precocial species in which CBP frequently occurs and in which a recent finding of nonrandom host-parasite relatedness has been interpreted to support the idea that relatedness and kin selection influence CBP. It turned out that possibilities to detect brood parasitism and accurately discriminate between kin and nonkin parasites are negligible in the species. The empirically parameterized model exercise revealed that relatedness and kin selection are unlikely explanations of CBP in the species.     

Survival of common goldeneye Bucephala clangula ducklings in relation to weather, timing of breeding, brood size, and female condition

The survival of common goldeneye Bucephala clangula ducklings during their first week of life was studied in relation to hatching date, brood size, female condition, and weather (temperature and precipitation) during the first week post-hatch by using data from radio-marked females and their broods. Also, age-specific variation in the survival of the young was determined until fledging (over 50 d of age). Survival was lowest in the first week after hatching. Hatching date, brood size, and first week temperature and precipitation were poor predictors of duckling survival during the first week after nest exodus. Instead, the ducklings of females in a better body condition survived better in their first week of life. The results suggest that weather does not have a direct effect on downy ducklings' survival, but the condition of the female seems to be an important determinant of the survival of common goldeneye ducklings.     

Avian wildlife reservoir of Campylobacter fetus subsp. jejuni, Yersinia spp., and Salmonella spp. in Norway.

Cloacal swabs from 540 wild-living birds were cultured for Campylobacter fetus subsp. jejuni, Yersinia spp., and Salmonella spp. The carrier rates detected were as follows: C. fetus subsp. jejuni, 28.4%; Yersinia spp., 1.2%; and Salmonella spp., 0.8%. All birds were apparently healthy when captured. C. fetus subsp. jejuni was isolated from 11 of the 40 bird species examined. Among birds inhabiting the city of Oslo, the highest isolation rate was found in crows (Corvus corone cornix) (89.8%), followed by gulls (Larus spp.) (50.0%) and domestic pigeons (Columba livia domesticus) (4.2%). The gulls and crows scavenge on refuse dumps. High carrier rates were also detected among the following birds from nonurban, coastal areas: puffin (Fratercula arctica) (51.3%), common tern (Sterna hirundo) (5.6%), common gull (Larus canus) (18.9%), black-headed gull (Larus ridibundus) (13.2%), and herring gull (Larus argentatus) (4.2%). The list of species harboring C. fetus subsp. jejuni also includes the Ural owl (Strix uralensis), goldeneye (Bucephala clangula), and reed bunting (Emberiza schoeniclus). The following five Yersinia strains were isolated: Y. kristensenii (two strains), Y. intermedia (two strains), and "Yersinia X2" (one strain). Four strains belonging to the genus Salmonella were isolated from three different species of gulls. These isolates were identified as S. typhimurium, S. indiana, and S. djugu. The results indicate that campylobacters are a normal component of the intestinal flora in several bird species, whereas Salmonella and Yersinia carriers are more sporadic.