Isolation of an Hswl Nav4 Influenza Virus from a Tufted Duck (Aythya fuligula) in Japan

A hemagglutinating agent was isolated from a tufted duck captured in Lake Shinji, Shimane Prefecture, Japan, and identified as influenza A by double immunodiffusion tests with the antiserum to influenza A virus ribonucleoprotein. The hemagglutinin of the isolate was antigenically related to that of A/New Jersey/8/76 but was not identical with it. The neuraminidase antigen of this Hswl subtype was closely related to that of A/turkey/Ontario/6118/68 and was shown to be Nav4 subtype. After experimental infection of 5-week-old SPF-chickens with the isolate, virus was recovered from various organs including the brain, despite the absence of signs of disease.     

Temporal genetic structure and relatedness in the Tufted Duck Aythya fuligula suggests limited kin association in winter

Conspecific aggregation of waterfowl in winter is a common example of animal flocking behaviour, yet patterns of relatedness and temporal substructure in such social groups remain poorly understood even in common species. A previous study based on mark‐recapture data showed that Tufted Ducks Aythya fuligula caught on the same day were re‐caught together in subsequent winters more often than expected by chance, suggesting stable assortments of ‘socially familiar’ individuals between wintering periods. The genetic relationships within these social groups were not clear. Based on 191 individuals genotyped at 10 microsatellite markers, we investigated the temporal genetic structure and patterns of relatedness among wintering Tufted Ducks at Lake Sempach, Switzerland, in two consecutive winters. We found no evidence of genetic differentiation between temporal groups within or between winters. The average levels of relatedness in temporal groups were low and not higher than expected in random assortments of individuals. However, Mantel tests performed for each sex separately revealed significant negative correlations between the pairwise relatedness coefficients and the number of days between the capture dates of pairs of wintering Tufted Duck in males and females. This pattern suggests the presence of a small number of co‐migrating same‐sex sibling pairs in wintering flocks of Tufted Ducks. Our findings provide one of the first genetic analyses of a common duck species outside the breeding season and contribute to the understanding of social interactions in long‐distance migratory birds.     

Laying date, clutch size and egg size of the Mallard Anas platyrhynchos and Tufted Duck Aythya fuligula

The effect of spring temperature on first egg date, laying period and last clutch date was studied in the Mallard and Tufted Duck. Seasonal clutch size and egg size trends were also examined. In years When Mallard laid early, Tufted Duck also did so. The first Mallard clutch was started earlier and laying period was longer in years with a high mean February temperature. The last clutch was started later in years with a high mean June temperature. In Tufted Duck the laying period increased and the last clutch was started later in years with high mean April temperatures.
Mean hatching date of Mallard clutches was later in years when the date of peak chironomid emergence was late.
In both species, clutch size declined through the season. Egg volume was not related to clutch size in either species, but egg volume in the Tufted Duck declined through the season. No difference in Tufted Duck egg size existed between sites, but the significance of egg size on duckling survival is discussed. Genetic factors related to individual consistency in egg size in Mallard may have obscured egg volume trends during the season because of renesting.     

Molecular mechanism of high altitude respiration: primary structure of a minor hemoglobin component from Tufted duck (Aythya fuligula, Anseriformes)

Avian hemoglobins have attracted much attention in view of the unique oxygen transport characteristics. The present study describes the primary structure of minor hemoglobin component HbD from Tufted duck (Aythya fuligula), a migratory bird seen in Pakistan during the winter season. Separation of the polypeptide subunits was achieved by ion exchange chromatography in the presence of 8M urea. Molecular masses of the intact protein as well as peptides obtained from chemical and enzymatic cleavages were determined by electrospray ionization mass spectrometry. The sequence was studied by automatic Edman degradation of the native chains and their tryptic/hydrolytic fragments in a gas-phase sequencer. Comparison of the hemoglobin sequence with the corresponding sequences of Anseriform representatives and other avian species shows residues like alpha(D)23 Asp, alpha(D)120 Asp as being specific to Tufted duck. The three-dimensional structure analyzed with the protein structure modeling package, WHAT IF, using the crystal structure coordinates of chicken hemoglobin (PDB code=1hbr) shows alpha(D)34 Val, alpha(D)38 Gln, and alpha(D)94 Asp as possible mediators offering alternate pathway for oxygen uptake and release thereby leading to distinct hypoxia tolerance in the Tufted ducks. Results are discussed with reference to function and evolution in the Anseriform representatives.     

Breeding site fidelity and winter admixture in a long-distance migrant, the tufted duck (Aythya fuligula)

Long-distance migrants are, by definition, highly mobile but it is poorly understood if this leads to high rates of gene flow and an essentially panmictic global population structure. Genetic divergence in migratory species could be promoted, for example, by fidelity to distinct migratory pathways. In this study, we investigate the population genetic structure of tufted duck (Aythya fuligula), a long-distance migrant with a largely continuous breeding distribution across Eurasia. Distinct, longitudinally oriented flyways have been postulated based on geographically disjunct wintering areas and are supported by evidence from ringing data. We generated sequences of the mitochondrial control region and multi-locus microsatellite genotypes for several hundreds of samples from the European and Asian breeding and wintering grounds including some individuals infected with highly pathogenic avian influenza virus H5N1. Significant differentiation between breeding sites was observed for both marker types, but F(ST) values were approximately 10 times higher for maternally inherited mitochondrial DNA than for biparentally transmitted nuclear markers. The genetic differentiation between the postulated European and Asian flyways was similar to that observed within continents and, in general, genetic divergence was not associated with geographic distance. Neither marker type showed evidence of genetic substructure among aggregations on the European wintering grounds. Our results suggest some breeding site fidelity, especially in females, but extensive population admixture on the wintering grounds. Several scenarios may explain the observed lack of genetic divergence between Europe and Asia including non-equilibrium conditions following a recent range expansion or contemporary gene flow across the postulated migratory divides.     

Molecular basis of bird respiration: primary hemoglobin structure component from Tufted duck (Aythya fuligula, Anseriformes)--role of alpha99Arg in formation of a complex salt bridge network

The primary structure of the major hemoglobin component, HbA (alpha(A)- and beta-chain), from Tufted duck (Aythya fuligula) is presented. The separation of the globin subunits was achieved by ion exchange chromatography on CM-cellulose in 8 M urea. The amino acid sequence was determined by automatic Edman degradation of native chains as well as tryptic and hydrolytic peptides in a gas-phase sequencer. The automated homology model was generated by the protein structure modeling package WHAT IF using the crystal structure coordinates of Bar-headed goose hemoglobin. The 3D structure prediction enables alpha99Arg and beta101Glu to emerge as a new intersubunit contact site not found in the hemoglobin structure of any other species. alpha99Arg forms a complex salt bridge network involving alpha99Arg-beta101Glu-beta104Arg-beta108Asp. Also the substitution at alpha34 --> Ile, alpha38 --> Gln and beta55 --> Leu serves to stabilize the oxy-structure, leading to higher oxygen affinity.     

Possible competitive interactions between overwintering tufted duck (Aythya fuligula (L.)) and fish populations of Lough Neagh,Northern Ireland: evidence from diet studies

The overwintering population of tufted duck (Aythya fuligula) on Lough Neagh, Northern Ireland, has varied over the last three decades, with numbers declining in the early 1980s but then increasing to former levels in the late 1980s. Population fluctuations of recently introduced roach (Rutilus rutilus) mirrored these trends. The present study explores the possibility that competition for benthic food resources is responsible for these changes by examining the diets of tufted duck, roach and other major fish species of the lake. Diet overlaps were generally high due to the common consumption of chironomid larvae. The diet of tufted duck overlapped most with that of roach because these two species were the only significant consumers of molluscs. This evidence provides further support for a tufted duck — roach competition hypothesis.     

Comparative mechanics of filter feeding in Anas platyrhynchos,Anas clypeata and Aythya fuligula (Aves,Anseriformes)

Summary The straining of seeds ranging in size from 0.01 to 4.6 mm was investigated in the filtering mechanisms of three anseriform species, Anas platyrhynchos, Anas clypeata, and Aythya fuligala. The morphology of the filtering mechanisms was studied by dissection and from microsections. The kinematic work envelope of the beaks was measured by stereotactic manipulation. The actual beak kinematics were analyzed by calculating the changes of the mouth volume from computer simulations and comparing the results with the amounts of water expelled. The performances of the filter and the water pump were measured with special collection boxes. The influence of the lamellae was estimated by removing them in whole or in part and measuring the performances again. The results show that if the size of the strained seeds increases, the gapes and amplitudes also increase (cf. bill rotations). Beak rotation is elevated for small kernels, even more elevated for slightly larger ones, but depressed for large kernels. However, neither frequencies nor phase shifts change between different moving elements. Simulation of these data by stereotactic manipulation of fresh material and by measuring gape sizes and mesh widths shows that the beak kinematics during straining keep mesh widths and gapes carefully adjusted to the seed size. The pumping and the filtering mechanisms influence each other mutually in setting boundary conditions on mouth kinematics. Beyond a certain kernel size, the necessity for mesh-width control sets a boundary on the increase of the water flow. Conversely, phase shifts, frequency changes and change of lingual amplitudes were restricted by the pumping mechanism. Drastic shortening of either dorsal mandibular or maxillary lamellae in Anas platyrhynchos and Aythya fuligula does not effect either the filter performances, the pump performances, or the beak kinematics, but these modifications do change the performances in Anas clypeata. The usually accepted assumption concerning food sieving was thus verified for Anas clypeata and falsified for the other two anseriform species. Therefore, a vortex model in addition to the sieving model, was developed, based on the assumption that local vortices cause inertia of particles so that small kernels are filtered by centrifugation and translation out of the main water flow. Combined effects of sieving and centrifugation occur when larger kernels are filtered. The kinematics of the filtering mechanism are highly flexible; therefore, a wide tolerance for seed sizes exists. However, the morphology of the filtering mechanism differs in the three species. Testing whether the anseriform filter mechanism is so plastic that the mechanism in each species has developed in such a way that the staple food is gathered most economically has shown that filtering of the staple food does indeed occur at the most efficient levels of maxillary rotation.     

Biodiversity-friendly designs for gravel pit lakes along the Drina River floodplain (the Middle Danube Basin,Serbia)

Wetlands Ecology and Management - Massive gravel excavation is one of the most destructive forces affecting riverine habitats in Europe. However, gravel pit lakes are also recognized as valuable...     

Effects of water quality on habitat use by lesser scaup (Aythya affinis) broods in the boreal Northwest Territories, Canada

The dynamics of Rhizophora mangle litter production and decomposition were studied in a tropical coastal lagoon on the Gulf of Mexico in Veracruz, Mexico over a year (October 2002–October 2003). This region is characterized by three seasons: northerly winds (called ‘nortes’), dry, and rainy. Annual litter production (1116 g m⁻²) followed a seasonal pattern with leaf litter as the main fraction (70%) with two peaks in the dry and one in the rainy season. Leaf decomposition was evaluated with two types of litter bag in each season: fine mesh (1×1 mm) and coarse mesh (3×7 mm). Decomposition data were adjusted to a single negative exponential model. The results indicated faster decomposition rates in the coarse litter bag and significant differences among seasons. However these differences occurred after the 60th day of decomposition, indicating that leaching and microbial action were responsible for more than 50% of mass loss. After this period, the effects of aquatic invertebrates were evident but depended on climatic conditions. In the rainy season, the gastropod Neritina reclivata was associated with increasing leaf decomposition rate. In the ‘nortes’ season, the effect of aquatic invertebrates was smaller, and there were no differences in the decay constants calculated for the two litter bag types. High litter production represents an important input of organic matter which, through decomposition, may represent an important source of C, N, and P in this aquatic system.     

Feeding ecology of the diving ducks pochard (Aythya ferina), tufted duck (A. fuligula), scaup (A. mania) and goldeneye (Bucephala clangula) overwintering on Lough Neagh, Northern Ireland

1. The diets of pochard (Aythya ferina), scaup (A. marila) and goldeneye (Bucephala clangula) overwintering on Lough Neagh are dominated by chironomid larvae, while molluscs are more important in that of tufted duck (A. fuligula). 2. Inshore areas of Lough Neagh offer poor feeding conditions for these diving ducks because chironomid larvae and molluscs are of small individual body size or low abundance. These factors lead to all four ducks foraging at least in part at depths greater than those usually exploited. 3. Due to their common consumption of molluscs, the diet of tufted duck shows a higher overlap with that of an introduced roach (Rutilus rutilus) population than with any other duck or fish species. 4. The feeding ecology of tufted duck and roach in Lough Neagh may form an example of distant competition and be at least partly responsible for recent fluctuations in the numbers of tufted duck.     

Movements and habitat use by immature Cinereous Vultures (Aegypius monachus) from the Caucasus

Capsule Juvenile and immature Cinereous Vultures from the Caucasus move large distances across undeveloped open-dry habitats in response to snowfall or high summer temperatures.

Aim To study local and long-range movements of Cinereous Vulture (Aegypius monachus), and investigate the influence of environmental variables on spatial and temporal distributions of the species on a large scale.

Methods We use 4-year-long location data from 6 juvenile Cinereous Vultures fitted with satellite-received transmitters to track their movements and obtain habitat suitability models.

Results A few months after fledging, Cinereous Vultures may migrate from the Caucasus as far south as the Arabian Peninsula. Their movements are concentrated in undeveloped open-dry habitats. High temperatures push the vultures to higher latitudes and altitudes, while reverse seasonal movements are triggered by the extent of snow cover.

Conclusions Our study shows the importance of the Arabian Peninsula and Iran as wintering areas for Cinereous Vultures. Long-distance movements by immature cinereous vultures are determined by climate seasonality, and in light of climate-warming scenarios for the next 100 years, there might be a shift in timing of the onset of the species seasonal movements and a change in the duration and geography of its wintering and summering.     

Early dry-season community structure and habitat use of young fish in tributaries of the River Sinnamary (French Guiana, South America) before and after hydrodam operation

We examined fish community structure and habitat use at the start of the dry seasons: (1) in 10 tributaries of the River Sinnamary (French Guiana) before and after the start of dam operation, and (2) in 10 upstream tributaries and at 10 littoral sites in the newly-created reservoir after the start of operation to assess the impact on fish juveniles of a hydroelectric dam built on the river's lower section. After the first year of dam operation, juvenile fish communities downstream of the dam showed an important decrease of the relative abundance of Characiformes, and Perciformes dominated. Principal components analysis revealed a distinct upstream-to-downstream progression in the juvenile fish communities with post-reservoir downstream and reservoir sites representing transitions between the upstream and pre-reservoir downstream sites. Canonical correspondence analysis and electivity indices of fish-habitat associations revealed three relatively distinct groups of sites, corresponding to the downstream, reservoir and upstream taxa. The proportion of juveniles presenting higher-than expected frequencies (Fisher's exact test) towards local environmental variables was higher for taxa more often caught in upstream sites. Inversely, juvenile taxa more frequently observed in downstream and reservoir sites appeared less selective towards local environmental characteristics. In the downstream reaches of the river, hydrodam operation is expected to drive the fish community towards a new biologically accommodated state where tolerant species will dominate and sensitive species will be lacking. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ranging patterns and habitat use of Sulawesi Tonkean macaques (Macaca tonkeana) in a human-modified habitat

The goal of this study was to investigate the ecological flexibility of Tonkean macaques (Macaca tonkeana) by examining how they respond to human-induced habitat alteration. To do so, I observed movement patterns, forest strata use, microhabitat use, and home range use in two groups that occupied habitats with different levels of human alteration and habitat quality in Lore Lindu National Park, Sulawesi, Indonesia. The group occupying the heavily altered habitat (Anca) spent a significantly greater proportion of time traveling on the ground than the group in minimally altered habitat (CH), and significantly more time than expected in microhabitats within their range that were characterized by greater alteration (e.g., agroforestry areas). There was no significant difference between the two groups in daily path length, despite differences in group size. The Anca group exhibited a greater home range area per individual than the CH group, and utilized a more limited area within their home range with greater intensity, relative to the CH group. Tonkean macaques therefore show considerable flexibility in response to anthropogenic disturbance by adjusting their use of forest strata to facilitate travel and increase foraging opportunities and by intensively using particular areas within their home range where known resources are present and predictably available.     

A sedentary fish on the move: effects of displacement on long-snouted seahorse (Hippocampus guttulatus Cuvier) movement and habitat use

To understand how a sedentary fish responds to displacement and identify key habitat characteristics for that fish, we translocated long-snouted seahorses (Hippocampus guttulatus) within their natural habitat but far beyond their home range. After displacement, we located these small fish using acoustic technology and collected environmental data where we captured, released, and relocated them. Displaced fish (n?=?9) moved much greater distances (max: 150?m; mean daily: 6.4?C48.2?m) than expected from known home range movements and there was no evidence of homing. Seahorses varied in the specific environments they moved towards but tended to move towards environments more similar in both depth and water current speed to their original capture locations than their release locations.     

Anadromy and marine habitat use of Lake trout (Salvelinus namaycush) from the central Canadian Arctic

Anadromy was documented in 16 lake trout, Salvelinus namaycush, from Canada's central Arctic using capture data and otolith microchemistry. For the first time, estuarine/marine habitat use was described for five individuals using acoustic telemetry. Age-at-first-migration to sea was variable (10–39 years) among individuals and most S. namaycush undertook multiple anadromous migrations within their lifetime. Telemetry data suggested that S. namaycush do not travel far into marine habitats and prefer surface waters (<2 m). These results further our collective understanding of the marine ecology of Arctic S. namaycush.     

The effect of boat sound on freshwater fish behavior in public (motorized) and wilderness (nonmotorized) lakes

Environmental Biology of Fishes - Freshwater lake soundscapes yield crucial information regarding biological, geological, and anthropogenic activity, yet is a relatively unexplored area of study....