Bucephala Clangula Research Articles

Presence of fish affects lake use and breeding success in ducks

Several previous studies indicate that presence of fish has negative effects on waterbirds breeding on lakes, owing either to competition for common invertebrate prey or fish predation on ducklings/chicks. However, others have reported results to the contrary and it remains unresolved what factors trigger, inhibit, and modulate fish–waterbird interactions. The present study was designed to test the effect of fish presence per se, with a minimum of variation in possibly confounding environmental variables. Thus, after stratifying for area, depth, altitude, pH, and total phosphorus we compared 13 lakes with and 12 without fish (mainly pike Esox lucius and perch Perca fluviatilis) with respect to (i) general species richness of waterbirds, (ii) species-specific utilization and breeding success of two dabbling ducks (mallard Anas platyrhynchos and teal Anas crecca) and a diving duck (goldeneye Bucephala clangula). General species richness of waterbirds was higher on fishless lakes. Overall use (bird days) and brood number of teal and goldeneye were higher on fishless lakes. The latter also had more benthic and free-swimming prey invertebrates compared to lakes with fish. Mallard use, mallard brood number, and abundance of emerging insects did not differ between lake groups. Generalized linear models including fish presence as factor and considering seven environmental variables as covariates, confirmed that all waterbird variables except mallard days and broods were negatively correlated to fish presence. There was also a residual positive relationship of lake area on general species richness, teal days, and teal broods. Our data demonstrate a stronger effect of fish presence on diving ducks and small surface feeding ducks than on large surface-feeding ducks. We argue that observed patterns were caused by fish predation on ducks rather than by fish–duck competition for common prey.

Interspecific Mate Choice and Hybridism in the Bufflehead, <em>Bucephala albeola</em>

Observations of a male Bufflehead (Bucephela albeola) paired with a female Common Goldeneye (Bucephela clangula) in northern Alberta in 1995 and of a hybrid male Common Goldeneye × Bufflehead photographed near Victoria, British Columbia, in March 2009 provide the first combined evidence of interspecific mate choice and out-crossing in Bucephala albeola. Since 1999, there have been at least 10 unofficial records, including photographs, of Common Goldeneye × Bufflehead hybrids posted on the Internet, as well as 6 records of hybridization with Hooded Mergansers (Lophodytes cucullatus). In all cases, where evident in Common Goldeneye × Buffleheads, gold eyes and pink feet were expressed and social affiliation was with Common Goldeneyes, suggesting matrilineage with that species. Because most attention is given to the hybrid - and to male hybrids at that - rather than to the progenitors, the theory of mate attraction, through sexual imprinting of males, is biased toward the paternal viewpoint. It appears that there is more plasticity in mate choice, particularly by the female. The opportunity to observe mate choice is much rarer than the hybrid outcome, while the odds of the latter have increased many fold in the last decade due to advances in Internet communication and digital photography. This exercise illustrates the ability of the Internet to amplify the prevalence of rare phenomena many fold over historical records.

Selenium Accumulation in Sea Ducks Wintering at Lake Ontario

Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer some trace elements, such as selenium (Se) to higher trophic levels. Se can be problematic for waterfowl and it often has been detected at elevated levels in organisms using the Great Lakes. There are, however, few data on hepatic Se concentrations in sea ducks, particularly during the winter at Lake Ontario. In this study, we evaluated interspecific differences and temporal trends in hepatic Se concentrations among BUFF (n = 77), COGO (n = 77), and LTDU (n = 79) wintering at Lake Ontario. All three species accumulated Se throughout winter, but COGO did so at a higher rate than did BUFF and LTDU. Overall, Se concentrations were higher in LTDU [mean = 22.7; 95% CI = 20.8-24.8 microg/g dry weight (dw)] than in BUFF ([mean = 12.3; 95% CI = 11.6-13.1 microg/g dw) and COGO ([mean = 12.0; 95% CI = 10.7-3.5 microg/g dw) throughout the winter. Se concentrations were deemed elevated (>33 microg/g dw) in 0%, 5%, and 19% of BUFF, COGO, and LTDU, respectively. Presently there are no data on Se toxicity end points for these species, so it is unclear how acquiring concentrations of these magnitudes affect their short- and long-term health or reproduction.

Reliability of egg morphology to detect conspecific brood parasitism in goldeneyes Bucephala clangula examined using protein fingerprinting

Eadie (1989) developed a method based on variation between females in egg length, width and weight to detect conspecific brood parasitism in the field: using these three egg measures, Euclidean distance between all pairs of eggs within a clutch is calculated, and if maximum Euclidean distance (MED) between any two eggs exceeds a threshold value the nest is considered parasitized. The MED method has been tested in Finnish and Scottish common goldeneye Bucephala clangula populations but the results have been contradicting. Here we use protein fingerprinting to assess the validity of the MED method. Data comprised 35 clutches of which we knew, based on protein fingerprinting, how many different females laid the clutch (range 1–5 females). The mean MED of non‐parasitized clutches (laid by 1 female only) was 1.470 (95% CI: lower 1.169, upper 1.771; n=21) and that of parasitized clutches (laid by 2 or more females) was 3.654 (95% CL: lower 3.083, upper 4.225; n=14). Using a MED>3.0 as a criterion to identify parasitized clutches 89% of all clutches were classified correctly either parasitized or non‐parasitized when compared to the identification based on protein fingerprinting. Clutch size and the number of females (beyond 2 females) did not affect the clutch MED, whereas the status of parasitism did. Repeatability of egg length, width and weight were: 0.63, 0.76 and 0.80, respectively, implying that, variation in these egg measures occurs among rather than within females. Our new results confirm that the MED method is reliable enough to detect parasitism in common goldeneye.

Egg Morphology Is An Unreliable Indicator of Intraspecific Nest Parasitism in Wood Ducks

Abstract. We examined the utility of the maximum Euclidean distance (MED) method, which was developed for the Common Goldeneye (Bucephala clangula) and is based on egg morphology, to detect parasitism in the Wood Duck (Aix sponsa). We used five polymorphic microsatellite loci to identify parasitized clutches and contributions by multiple females. Three-egg clutches randomly assembled from eggs of one female were less variable than those of three females, indicating that variation within females was less than variation among females. Although variation in egg morphology in parasitized clutches was greater than among eggs laid by one female, extensive overlap in MED values precluded the identification of a clear boundary to distinguish between parasitized and unparasitized clutches. The best MED criterion misclassified 28% of nests. Our results suggest that egg morphology should not be used to detect parasitism in Wood Ducks.

Examination of presence of specific antibodies against avian influenza virus in some species of wild birds

Infections caused by the avian influenza virus have been known for a long time and they are present, to a smaller or greater extent, in both extensive and intensive poultry production in many parts of the world. Epidemiological investigations have established a definite significance of the population of wild birds in maintaining and spreading this infection. Avian influenza is a zoonosis, and the virus has a great potential for causing mortality in humans, in particular its subtypes H5 and H7, which is why it has lately been provoking much attention among scientists and experts, as well as the general public. The objective of the work was to catch a certain number of wild birds in several locations in the Republic of Serbia, to identify them, and to collect samples of their blood serum for the determination of specific antibodies against the avian influenza virus. Birds were caught in ten locations in a manner that was safe for the birds themselves, as well as for the staff that did the catching. The birds were caught in especially produced nets, and in some cases in special traps. The caught wild birds were identified using the methods described in reference literature. All the names of the wild birds were coordinated with the valid Serbian nomenclature of European birds, prepared by prominent ornithologist and bird lover Milan Ružić. Following catching and identification, blood samples were taken from the birds from the wing vein (in bigger birds) or from the leg vein (in smaller birds). In taking blood samples from wild birds, all the principles of asepsis and antisepsis were followed in order to prevent any possibility of infection. After that, the birds were returned to their natural habitat, to the same locations in which they were caught. Serums were isolated from the taken blood samples and they were stored at -20oC until the final examinations. A total of 46 species of wild birds were identified among a total of 259 birds from which 259 samples of blood serum were isolated. The following were used for the detection of the presence of specific antibodies against the avian influenza virus in blood serum samples of wild birds: agar gel precipitation (AGP), the hemagglutination inhibition test (HI) for subtypes H5 and H7, the cELISA test with antigen for the A type avian infleunza virus, and the cELISA test with antigen for subtype H5 of the avian influenza virus. Due to the fact that about 360 different species of wild birds live in the Republic of Serbia, the number of 46 identified species covered by these investigations account for 12.77% of the total number of bird species present in Serbia, which is considered a good sample. Specific antibodies against the A type avian influenza virus were established in serum samples of only 9 of the 259 birds covered by examinations using the cELISA test. Of the 46 identified wild bird species, 6 belonged to birds that live exclusively in water habitats and are considered a reservoir of the avian influenza virus (white stork, mallard, mute swan, common pochard, common goldeneye, and Eurasian coot). Among the listed species, particular attention was drawn to 4 species of wild birds of the order Anseriformes and the family Anatidae (mallard, mute swan, common pochard, common goldeneye) of which there were 30 birds among the total of 259 examined. In the 30 blood serum samples of the listed bird species, specific antibodies against the A type avian influenza virus were established in 9 (30%) serum samples using cELISA. Specific antibodies against the avian influenza virus subtype H5 were established in 3 serum samples of mute swans (one serum sample originated from a mute swan which was tagged in Poland) and in one blood serum sample of a common pochard, or a total of 4 (13.33%) serum samples, using the hemagglutination inhibition test. Specific antibodies against the avian inluenza virus subtype H7 were established in 3 (10%) blood serum samples, in two serum samples from mallards and one sample from a mute swan, using the hemagglutination inhibition test. Specific antibodies against the avian influenza virus type A were not established in any examined bird species using the AGP test. In the population of wild bird species in the Republic of Serbia covered by these investigations, specific antibodies against the avian influenza virus were established only in serum samples of birds of the family Anatidae. Specific antibodies against the avian influenza virus type A established in 3 (6.52%) species of wild birds, and against subtypes H5 and H7 in 2 (4.34%) of the total of 46 examined species. The sensitivity of the cELISA test for the avian influenza virus subtype H5 and the hemagglutination inhibition test for subtype H5 amounted to 100%.

British Ornithologists’ Union Records Committee: 37th Report (October 2008)

British Ornithologists’ Union Records Committee: 37th Report (October 2008)

Nesting ecology of Common Goldeneyes and Hooded Mergansers in a boreal river system

Common Goldeneyes (Bucephala clangula) and Hooded Mergansers (Lophodytes cucullatus) are common cavity-nesting ducks but the importance of fast-flowing rivers as suitable nesting habitat may have been overlooked. We monitored the use of >90 nest boxes installed along a boreal forest river over a 5-year period. A high nest box occupancy rate was reached in the second year (40%) and was maintained thereafter (48 to 55%). On average, 35 nest boxes were occupied by goldeneyes and 11 by mergansers each year. Laying date was similar between the two species but merganser nests hatched slightly later. Both species had similar clutch sizes but merganser nests contained more eggs than goldeneye nests when heterospecific parasitic eggs were included. On average, 16% of goldeneye nests were parasitized by mergansers, and 49% of merganser nests were parasitized by goldeneyes. Density of suitable natural cavities in the area was relatively low suggesting the high occupancy rate of nest boxes may be a response to lack of suitable cavities. Nest box use was positively related to the total surface area of ponds in the vicinity and negatively to distance to the river. Use of nest sites along fast-flowing rivers appears to be an opportunistic strategy and may be dependant on the presence of nearby ponds and lakes.

Changes in numbers and distribution of wintering waterfowl in Sweden during forty years, 1967–2006

Regular midwinter counts of waterfowl (included in the International Midwinter Counts, IWC, organized by what is now Wetlands International) has been undertaken in Sweden since the start in 1967 and are still going on, now as a part of the National Environmental Monitoring Programme. After the first exploratory years including country-wide surveys in 1971–1973 undertaken both from the ground, the air and boats, the programme was standardized to cover an adequate sample of coastal and inland sites of south Sweden for the production of annual midwinter population indices for important species (areas further north in Sweden are normally ice-covered and without importance for waterbirds in winter). Further large scale surveys were undertaken in 1987–1989, 1993 and 2004 (country-wide survey). The programme did not cover the seaducks in offshore areas (later included in a special programme). The present contribution analyses the first 40 years of midwinter counts in Sweden, especially with the aim to elucidate changes in distribution and numbers of the different species during this time series. During the period there was a marked change in the winter weather and especially the ice situation in Sweden in January, being a factor of importance for the wintering waterbirds. During the years 1967–1987 there were five really hard ice-winters, whereas in the latter part of the period there was no really hard ice-winter. Comparisons between the country-wide surveys in 1971 and 2004 showed a marked increase from 172,000 to 627,000 individuals excluding the offshore species Clangula hyemalis and Melanitta spp. Anas platyrhynchos increased from 67,000 to 150,000, Aythya fuligula from 54,000 to 230,000 and Bucephala clangula from 19,000 to 75,000. Increases were also found in most of the other species. In addition, Anas penelope and Podiceps cristatus established new wintering traditions in south Sweden. Midwinter indices for nine out of ten species showed significantly increasing trends over the 40 years, no species decreasing. In Anas platyrhynchos and Aythya fuligula the indices showed fluctuations around a steady level, then a marked increase followed after the last cold winter, whereas species like Bucephala clangula and Mergus serrator showed increasing trends from the start of the counts. Fulica atra crashed markedly after one cold winter and remained for years on a low level before recovering but the overall trend was increasing. To a large extent the increases found are probably due to the milder winters in later years, which also led to changes in winter distribution within the country, also being reflected in the regional totals for different species. Part of the increases does also reflect genuine population increases as show by comparisons with IWC results from other countries.

Habitat-patch occupancy in the common goldeneye (Bucephala clangula) at different stages of the breeding cycle: implications to ecological processes in patchy environments

We studied the pattern of habitat-patch occupancy of radio-tagged common goldeneye ( Bucephala clangula (L., 1758)) females in two sequential stages of the breeding season, the nest stage and the brood stage, and whether the resources needed in nesting and brood-rearing are spatially inter-related as revealed by patch occupation rate of goldeneye females in these stages. We also studied patch-specific factors potentially explaining the rate of patch occupation separately during the nest stage and the brood stage. There was no association in patch occupation rate between the nest stage and the brood stage, indicating that all the critical resources needed to complete a successful breeding cycle were not met within the same habitat patch. At the nest stage, patch occupation rate increased with nest-site availability and decreased with nest predation rate but was not affected by vegetation luxuriance or patch size. Vegetation luxuriance had a positive effect on patch occupation rate at the brood stage, whereas nesting success of the focal patch had no effect. Results suggest that nest-site selection and brood-stage habitat selection are governed by different ecological factors. We conclude that breeding-stage-specific resource requirements redistributed individuals among habitat patches across the landscape, implying dynamic distribution of ducks between nesting and brooding stage.

Trace Element Concentrations in Wintering Waterfowl from the Great Salt Lake, Utah

The Great Salt Lake (GSL) is an important region for millions of migratory waterbirds. However, high concentrations of some trace elements, including Hg and Se, have been detected within the GSL, and baseline ecotoxicological data are lacking for avian species in this system. We collected common goldeneye (Bucephala clangula), northern shoveler (Anas clypeata), and green-winged teal (A. crecca) from the GSL during the winters of 2004-2005 and 2005-2006 to evaluate sources of variation in liver trace element concentrations. Hg concentrations were among or exceeded the highest values reported in the published literature for common goldeneye, northern shoveler, and green-winged teal. Average Hg (total) concentrations of common goldeneye peaked in midwinter, whereas average Se concentrations peaked during late winter. During late winter, 100% and 88% of female goldeneye contained elevated concentrations of Hg [>or=1.0 microg/g wet weight (ww)] and Se (>or=3.0 microg/g ww), respectively, and 5% and 14% contained potentially harmful amounts of Hg (>or=30.0 microg/g ww) and Se (>10.0 microg/g ww), respectively. Similarly, 30% and 16% of male goldeneye contained potentially harmful concentrations of Hg and Se, respectively. Concentrations of Hg and Se were elevated in 100% and 79%, respectively, of northern shoveler samples (sexes combined) collected during February. We suggest that waterfowl contain biologically concerning amounts of Hg and Se during winter while on the GSL and further research is needed to evaluate the effect of these elements on GSL waterbirds.

DIETARY OVERLAP OF SYMPATRIC DIVING DUCKS DURING WINTER ON NORTHEASTERN LAKE ONTARIO

Abstract Food resources available to diving ducks wintering on the Great Lakes have changed dramatically since the introduction of dreissenid mussels (Dreissena bugensis and D. polymorpha). We investigated the diets of Buffleheads (Bucephala albeola), Common Goldeneyes (B. clangula), and Long-tailed Ducks (Clangula hyemalis) during winter, 2002–2004, on northeastern Lake Ontario and determined the levels of dietary overlap. Dietary niche-breadth values were low, and dietary overlap values (prey size and type) were high for all species. Ducks primarily consumed high-quality, energy-dense prey (Amphipoda, Chironomidae), which were abundant. Our results highlighted three patterns: (1) dreissenid mussels constituted 85% of the macroinvertebrate community in Lake Ontario but were consumed in relatively low amounts during winter, (2) foods of high energy-density such as Amphipoda and Chironomidae were likely abundant enough for ducks to selectively feed on them, and (3) some constraint caused ducks to select en...

Interaction between Macroinvertebrate Abundance and Habitat Use by Diving Ducks during Winter on Northeastern Lake Ontario

Although numbers of buffleheads ( Bucephala albeola), common goldeneyes ( Bucephala clangula) and long-tailed ducks ( Clangula hyemalis) over-wintering on Lake Ontario have increased substantially over the past two decades, factors influencing habitat use and the potential for competition have not been investigated. The purpose of this study was to determine the relationship between prey availability and community structure of diving ducks during winter on northeastern Lake Ontario. Benthic and nektonic samples collected during fall, winter, and spring 2002–2004 indicated that macroinvertebrate numbers differed by location but generally did not decline throughout winter. Large accumulations of macroinvertebrates, apparently moved by wave action and currents, were documented in nearshore areas. Surveys showed that diving ducks congregated in mixed species flocks within areas of higher food abundance. Mixed species flocks were common in nearshore areas, likely because energydense foods (Amphipoda and Chironomidae) were abundant in the narrow zone of shallow water, close to shore. Although macroinvertebrate numbers likely affected habitat use by diving ducks, birds did not greatly reduce abundance of macroinvertebrates. It is unlikely that exploitative competition was occurring and interference competition appeared below threshold levels that would cause species to spatially segregate. Overall, our results suggest that food availability is not a limiting factor for buffleheads, common goldeneyes, or long-tailed ducks wintering on northeastern Lake Ontario.

Common Goldeneye Breeding in the Eastern Canadian Boreal Forest: Factors Affecting Productivity Estimates

Abstract We conducted multiple Common Goldeneye (Bucephala clangula) aerial surveys between 1 May and 31 July 2004 and 2005 on the Peribonka River, where a new hydroelectric reservoir will be created in 2007. We also conducted single pair and brood surveys on randomly chosen 5 × 5-km plots on the River drainage basin. Objectives were to assess the validity of the impact assessment surveys of 2002, examine the variation in pair and brood numbers, and determine recruitment and habitat characteristics related to productivity. During both years, the number of indicated breeding pairs (IBPs) declined steadily through May, whereas the social index (paired males/lone males) remained stable, declining only when few IBPs were located. However, backdated number of paired and lone males from observed broods suggested that the number of pairs remained maximal and constant during a three-week period centered on the fourth week of May in 2004 and the second week of May in 2005. IBP density (IBPs/10 km of shoreline) was...

Sarcocystis sp. from the goldeneye (Bucephala clangula) and the mallard (Anas platyrhynchos): cyst morphology and ribosomal DNA analysis

By light microscopy, cysts of Sarcocystis sp. (cyst type I) from the goldeneye (Bucephala clangula) seemed filamentous with a smooth and thin (<1 microm) cyst wall. Ultrastructurally, the cyst wall surface was irregular with minute undulations of the primary cyst wall. These sarcocysts had type-1 cyst wall. Cystozoites were banana-shaped and measured 7.0-8.5 microm in length. By light microscopy, cysts of Sarcocystis sp. (cyst type II) from the mallard (Anas platyrhynchos) were ribbon-shaped, very long, and thin. On the surface of the wall (up to 1.5 microm), they had palisade-like villar protrusions closely crowded together. Electron micrographs showed villar protrusions (up to 1.3 microm in length) different in size and shape. The latter had short microprojections especially obvious in the oblique sections. Cystozoites were slightly bent with blunt ends, broader at one end, and measured 13.0-16.1 x 1.8-2.5 microm. Phylogenetic analysis based on the comparison of partial 28S rRNR gene sequences of Sarcocystis sp. (cyst type II) derived from the mallard, Sarcocystis sp. (cyst type I) and Sarcocystis sp. (cyst type III) both derived from the white-fronted goose (Anser albifrons) suggested that these sequences belonged to separate Sarcocystis species.

The Timing of Waterfowl Arrival and Dispersion During Spring Migration in Labrador

Weekly aerial surveys were conducted in central Labrador during the spring staging period (27 April to 29 May, 2000), and the relative abundance of waterfowl was documented. Anas rupribes (American Black Duck) and Bucephala clangula (Common Goldeneye) were among the first species to arrive, while peak waterfowl diversity occurred on the latest survey date. Overall, Branta canadensis (Canada Geese) were the most abundant species, followed by American Black Duck and Anas crecca (Green-winged Teal). As expected, the relative abundance of these species varied by date and region. By the time of the last survey on 29 May, average flock size had decreased for most species, most likely corresponding with the start of breeding and nest initiation. Our findings could be useful as baseline information for future studies of climate change, may have implications for the management of the aboriginal spring hunt, and also might be used to mitigate the effects of military flying activity.

Distribution, Diet and Dive Behavior of Barrow’s and Common Goldeneyes during Spring and Autumn in the St. Lawrence Estuary

Barrow’s (Bucephala islandica) and Common (B. clangula) goldeneyes winter in large numbers in the St. Lawrence estuary and little is known of their distribution and diet. The objective of the study was to characterize how these two similar species, co-existed in the St. Lawrence estuary during the non-breeding season. Their local distribution, diet, and dive efficiency were compared. There was little overlap in habitat use by both goldeneyes. Their distribution was not correlated in the autumn (r = 0.04) but was in the spring (0.68). Autumn and spring distributions were more correlated in Common Goldeneyes (r = 0.82) than in Barrow’s Goldeneyes (r = 0.49). Both species moved to the north shore of the estuary during January and February 1999 as south shore intertidal areas froze. Barrow’s Goldeneyes foraged in larger flocks than Common Goldeneyes (x̄ = 20.3 vs 9.8 birds) and flocks were larger in autumn than spring. Both species fed on amphipods but differed in their use of gastropods (Barrow’s Goldeneye) and polychaetes (Common Goldeneye). Dive duration was similar in both species but varied between areas. Pause duration was shorter in Common Goldeneyes than in Barrow’s Goldeneyes but was not affected by area. Dive efficiency was higher in Common Goldeneyes than Barrow’s Goldeneyes and varied between areas. The predominance of polychaetes in the diet of Common Goldeneyes and of amphipods in the diet of Barrow’s Goldeneyes had not been highlighted before. These species provide a good example of niche differentiation between closely related species.

USE OF NEST BOXES BY GOLDENEYES IN EASTERN NORTH AMERICA

We evaluated and monitored use of 105–133 nest boxes by Common Goldeneye (Bucephala clangula) and Barrow's Goldeneye (Bucephala islandica) during 1999–2004 on 60 lakes of high plateaus of the Laurentian Highlands, in the boreal forest of Québec, Canada. Only three species of birds used nest boxes regularly, American Kestrel (Falco sparverius), Barrow's Goldeneye, and Common Goldeneye. The proportion of nest boxes used by goldeneyes in 2000–2004 ranged from 23 to 43% whereas hatching success ranged from 37 to 67%. Successful Barrow's and Common goldeneye clutches averaged 6.76 ± 0.38 (SE, n = 29) and 7.77 ± 0.44 eggs (n = 31), respectively. Predation in nest boxes was not a major mortality factor. Goldeneyes used all nest boxes independent of their location but reproductive success was lower in nest boxes 25–160 m from shore in clearcuts. The number of Barrow's and Common goldeneye breeding pairs increased between 1999 and 2003, but number of broods remained stable after an increase in 2000.

Avian Influenza Virus Screening in Wild Waterfowl in Norway, 2005

The prevalence of influenza A virus infection, and the distribution of different subtypes of the virus, were studied in 604 geese and ducks shot during ordinary hunting 2005. The study was based upon molecular screening of cloacal swabs taken by the hunters. The sampling included the following species: greylag (Anser anser), mallard (Anas platyrhynchos), wigeon (Anas penelope), teal (Anas crecca), goosander (Mergus merganser), tufted duck (Aythya fuligula), common scoter (Melanitta nigra), goldeneye (Bucephala clangula), and red-breasted merganser (Mergus serrator). The samples found to be positive in the initial pan-influenza A virus reverse transcription-polymerase chain reaction (RT-PCR) were further subtyped by using a specific H5 RT-PCR and full-length RT-PCRs for the hemagglutinin (HA) and neuraminidase genes. None of the greylag samples (0/185) were positive for influenza Avirus, whereas 19.1% of the ducks (80/419) were positive. The prevalences of influenza A virus in the different duck species were as follows: mallard, 20.4% (58/284); wigeon, 12.5% (8/64); teal, 30.9% (13/42); goosander, 0% (0/5); tufted duck, 0% (0/4); common scoter, 14.3% (1/7); goldeneye, 0% (0/11); and red-breasted merganser, 0% (0/2). H5N1 subtype was found in one mallard and H5N2 subtype in another mallard and one teal. Sequencing of the HA gene identified all three viruses as low-pathogenic strains, closely related to low-pathogenic H5 influenza A viruses evidenced in recent years in Sweden and the Netherlands. The other subtypes identified included H1N1, H2, H3N2, H3N8, H6N1, H6N2, H6N8, H8N4, H9N2, H11N9, and H12 in mallards; H3N2, H6N2, H6N8, and H9N2 in teals; and H6N2 in wigeons and common scoter.

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.