Spread of Avian Influenza Viruses by Common Teal (Anas crecca) in Europe

Since the recent spread of highly pathogenic (HP) H5N1 subtypes, avian influenza virus (AIV) dispersal has become an increasing focus of research. As for any other bird-borne pathogen, dispersal of these viruses is related to local and migratory movements of their hosts. In this study, we investigated potential AIV spread by Common Teal (Anas crecca) from the Camargue area, in the South of France, across Europe. Based on bird-ring recoveries, local duck population sizes and prevalence of infection with these viruses, we built an individual-based spatially explicit model describing bird movements, both locally (between wintering areas) and at the flyway scale. We investigated the effects of viral excretion duration and inactivation rate in water by simulating AIV spread with varying values for these two parameters. The results indicate that an efficient AIV dispersal in space is possible only for excretion durations longer than 7 days. Virus inactivation rate in the environment appears as a key parameter in the model because it allows local persistence of AIV over several months, the interval between two migratory periods. Virus persistence in water thus represents an important component of contamination risk as ducks migrate along their flyway. Based on the present modelling exercise, we also argue that HP H5N1 AIV is unlikely to be efficiently spread by Common Teal dispersal only.     

Moults and plumages and testicular regression of post-breeding male Blue-winged teal (Anas discors) and Northern shovelers (Anas clypeata)

Moults and plumages and testicular regression were compared in post-breeding male Northern shovelers ( Anus clypeala ) and Blue-winged teal ( A. discors ). Sequence of moults and plumages was similar between species, except that Northern shovelers became flightless before completion of pre-basic moult and initiated pre-alternate moult before complete regrowth of primaries. Testicular regression was similar in both species, occurring in a two-stage process of from four to six weeks. In all cases, both species had finished testes regression before the initiation of the flightless period. In both species, the lcft testis was larger in spring, regressed slower, and was larger after regression than the right testis.     

Comparative toxicity of lead shot in black ducks (Anas rubripes) and mallards (Anas platyrhynchos)

In winter, pen-reared and wild black ducks (Anas rubripes), and game farm and wild mallards (Anas platyrhynchos), maintained on pelleted feed, were sham-dosed or given one number 4 lead shot. After 14 days, dosed birds were redosed with two or four additional lead shot. This dosing regimen also was repeated in summer using pen-reared black ducks and game farm mallards. Based upon mortality, overt intoxication, weight change, delta-aminolevulinic acid dehydratase activity and protoporphyrin concentration, black ducks and mallards were found to be equally tolerant to lead shot. However, captive wild ducks were more sensitive than their domesticated counterparts, as evidenced by greater mortality and weight loss following lead shot administration. This difference may be related to stress associated with captivity and unnatural diet.     

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.     

Isolation of Newcastle disease virus from teals (Anas crecca) in Iran.

Eight of 30 teals (Anas crecca) died several days following capture and Newcastle Disease Virus (NDV) was isolated from all eight. Brains from the dead birds were homogenized and inoculated into chicken embryos. The allantoic fluid from the embryos were inoculated into 10 domestic chickens susceptible to NDV and 10 chickens immunized against NDV. Eight of 10 (80%) susceptible chickens died, while the immunized chickens remained healthy. Anti-NDV serum showed complete homology against NDV and the eight isolates.     

Acute toxicity of lead, steel, and an iron-tungsten-nickel shot to mallard ducks (Anas platyrhynchos)

Twenty mallards (Anas platyrhynchos) of both sexes were dosed by oral gavage with Heavi-Shot (H-S; Environ-Metal, Inc., Sweet Home, Oregon, USA) pellets, 20 with steel shot, and 10 with lead (Pb) pellets, all of equal size. All pellets were fired from a shotgun into an absorbent material, retrieved, and weighed prior to introduction into the ducks. Birds were fed whole kernel corn and grit and observed for signs of toxicity for 30 days following dosing. Hevi-Shot pellets lost an average of 6.2% of their mass and steel shot pellets lost 57% of their mass in the birds' gizzards. Almost all (90%) of the Pb shot dosed birds died before the end of the study, while no mortality was observed in the steel or H-S dosed groups. Even though total food consumption differed between the H-S and steel shot groups, mean bird weight change was not different. There were no significant morphologic or histopathologic abnormalities of the liver and kidney in the H-S and steel shot groups. Results indicated that mallards dosed orally with eight No. 4 H-S pellets were not adversely affected over a 30-day period, and that H-S provides another environmentally safe nontoxic shot for use in waterfowl hunting.     

Two New Kalyptorhynchia (Turbellaria) from the Coast of Northern New England,USA1

Cystiplana rubra sp.n. and Crassicollum musculare gen. et sp.n. are described and their taxonomy discussed. C. rubra (family Cystiplanidae Karling, 1964) is distinguished by red pigmented stripes, two pairs of cuticular pieces within the copulatory bulb, a small male atrium posterior to the copulatory bulb, and a two part atrial bulb. C. musculare is characterized by a large, unpaired prostatic vesicle with two distinct regions of secretory products, a muscular penis papilla with a small apical stylet, large muscle bolsters bracketing a glandular evagination of the genital atrium, and a large sphincter encircling the genital canal. A new family of Eukalyptorhynchia, Crassicollidae, is erected. Notes on some biological aspects of these species are included.     

Sobolevicanthus transvaalensis n.sp. (Cestoda: Hymenolepididae) from the Cape Teal (Anas capensis Gmelin, 1789)

Summary Sobolevicanthus transvaalensis n.sp. is described from the Cape Teal, Anas capensis Gmelin, 1789, collected in the Republic of South Africa. The new species possesses 8 skrjabinoid hooks 78–88 m long (mean 85 m) and a short claviform cirrus-sac 79–143 m long and resembles S. javanensis (Davis, 1945) and S. terraereginae (Johnston, 1913). It can be distinguished from S. javanensis by its shorter cirrus-sac and smaller cirrus diameter, and by differences in the morphology of the accessory sac and vagina and in their position relative to the cirrus-sac. It can be separated from S. terraereginae on the basis of cirrus length and diameter. The basal diameter of the cirrus in S. terraereginae is three times that in S. transvaalensis. ac]19830414     

Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca)

The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used tool for understanding the ecology and behaviour of animals. However, waterfowl remain poorly explored in this context. In an aviary experiment we derived a functional response curve for teal (Anas crecca) foraging on rice (Oryza sativa) seeds. We found a linear relationship between intake rate and seed density, as expected for a filter-feeder. At high seed densities we found a threshold, above which intake rate still increased linearly but with a lower slope, possibly reflecting a switch from filter-feeding to a scooping foraging mode. The present study shows that food intake rate in teal is linearly related to food availability within the range of naturally occurring seed densities, a finding with major implications for management and conservation of wetland habitats.     

A comparison of two methods to establish the prevalence of lead shot ingestion in mallards (Anas platyrhynchos) from The Netherlands

Two collection methods for screening the mallard (Anas platyrhynchos) population in the Netherlands for the ingestion of spent lead shot were compared. One method consisted of examination of gizzards from mallards shot by hunters (n = 2,859) and the other method consisted of examination of gizzards from mallards caught in duck traps (n = 865). The 95% confidence interval of lead shot ingestion in the mallard population estimated by the first method was 1.7 to 2.9% and by the second method 1.1 to 3.1%. These values were not significantly different. From the numbers of lead pellets embedded in the gizzard wall in hunter-killed and trapped mallards it was estimated that at least 22 to 68% of the trapped ducks had been hit by lead shot previously, but survived. Furthermore, this study shows that it is reasonable to assume that a substantial part of the pellets which are identified (in this study and other studies) as ingested, may well have been shot into the gizzard lumen at some time before the birds were actually killed. To avoid lead poisoning in mallards and in raptors depredating waterfowl hit by lead shot, a change to steel shot is advocated.     

A parapatric propensity for breeding precludes the completion of speciation in common teal (Anas crecca, sensu lato)

Speciation is a process in which genetic drift and selection cause divergence over time. However, there is no rule dictating the time required for speciation, and even low levels of gene flow hinder divergence, so that taxa may be poised at the threshold of speciation for long periods of evolutionary time. We sequenced mitochondrial DNA (mtDNA) and eight nuclear introns (nuDNA) to estimate genomic levels of differentiation and gene flow between the Eurasian common teal (Anas crecca crecca) and the North American green‐winged teal (Anas crecca carolinensis). These ducks come into contact in Beringia (north‐eastern Asia and north‐western North America) and have probably done so, perhaps cyclically, since the Pliocene–Pleistocene transition, ～2.6 Ma, when they apparently began diverging. They have diagnosable differences in male plumage and are 6.9% divergent in the mtDNA control region, with only 1 of 58 crecca and 2 of 86 carolinensis having haplotypes grouping with the other. Two nuclear loci were likewise strongly structured between these teal (Φ_st ≥ 0.35), but six loci were undifferentiated or only weakly structured (Φ_st = 0.0–0.06). Gene flow between crecca and carolinensis was ～1 individual per generation in both directions in mtDNA, but was asymmetrical in nuDNA, with ～1 and ～20 individuals per generation immigrating into crecca and carolinensis, respectively. This study illustrates that species delimitation using a single marker oversimplifies the complexity of the speciation process, and it suggests that even with divergent selection, moderate levels of gene flow may stall the speciation process short of completion.     

Plant dispersal by teal (Anas crecca) in the Camargue: duck guts are more important than their feet

1. Migratory waterbirds are major vectors for the dispersal of aquatic plants. However, quantitative field studies of the frequency of transport are scarce, and the relative importance of internal and external transport remains unclear. 2. We quantified and compared the rates of internal and external transport of aquatic plant propagules by teal (Anas crecca) in the Camargue (southern France), inspecting the lower gut contents of birds that had been shot (n = 366) and washing birds that had been live‐trapped (n = 68) during the winters of 2006–2007 and 2007–2008. 3. Intact propagules (n = 902) of 21 plant taxa were recorded in the rectum of teal, of which 16 germinated or were shown to be viable. Intact propagules were recorded in the rectum of 20% of teal, with up to 171 propagules per individual bird. Chara oogonia were most abundant (60% of intact propagules), suggesting that small size favours internal transport. Eleocharis palustris, Juncus spp. and Potamogeton pusillus (17, 7 and 6% of intact propagules, respectively) were also very abundant. 4. Intact propagules (n = 12) of 10 plant taxa were found on the outside of live teal, and four of these taxa later germinated. Intact propagules were found on 18% of teal. No teal was found to carry more than one propagule externally. There was no difference in size between propagules transported internally and externally. 5. Teal are major dispersers of plants within the Camargue, despite being highly granivorous. Contrary to widespread assumptions in the literature, endozoochory by ducks appears to be a much more important mode of dispersal for aquatic plants than exozoochory. We found no evidence of changes in the probability of plant propagule dispersal at a landscape scale over the course of the winter, so propagule production and zoochory appear to be decoupled over time in aquatic systems.     

The relation between the feeding activity of wintering shovelers (Anas clypeata) and the horizontal distribution of zooplankton in Lake Teganuma,Japan

We investigated seasonal changes in the number and feeding activity of Shovelers wintering in Lake Teganuma in connection with temporal and horizontal fluctuations of zooplankton, and analyzed esophageal contents of a captured Shoveler. Zooplankton community was dominated by rotifers followed by copepods during the study period. Horizontal distribution of both invertebrate taxa differed; rotifers most abundant in the western and eastern parts of the lake in February–March, and cyclopoid copepodids and nauplii more common in the northeast area of the eastern portion of the lake. The number and feeding activity of Shovelers increased from January to March in the northeast area of Lake Teganuma. A Shoveler captured in the area had mostly consumed cyclopoid copepodids despite the fact that rotifers dominated in the zooplankton community at that location. These results suggest that the horizontal distribution and feeding activity of the Shovelers were correlated with the distribution of the cyclopoid copepodids.     

Role and Value of Nitrogen Regulation Provided by Oysters (Crassostrea virginica) in the Mission-Aransas Estuary,Texas, USA

Suspension-feeding activities of oysters impart a potentially significant benefit to estuarine ecosystems via reduction of water column nutrients, plankton and seston biomass, and primary productivity which can have a significant impact on human well-being. This study considered nitrogen regulation by eastern oysters Crassostrea virginica in the Mission-Aransas Estuary, Texas, USA, as a function of denitrification, burial, and physical transport from the system via harvest. Oyster reefs were estimated to remove 502.5 kg N km⁻² through denitrification of biodeposits and 251.3 kg N km⁻² in burial of biodeposits to sediments. Nitrogen is also physically transported out of the estuary via harvest of oysters. Commercial harvest of oysters in the Mission-Aransas Estuary can remove approximately 21,665 kg N per year via physical transport from the system. We developed a transferable method to value the service of nitrogen regulation by oysters, where the potential cost equivalent value of nitrogen regulation is quantified via cost estimates for a constructed biological nutrient removal (BNR) supplement to a wastewater treatment plant. The potential annual engineered cost equivalent of the service of nitrogen regulation and removal provided by reefs in the Mission-Aransas Estuary is $293,993 yr⁻¹. Monetizing ecosystem services can help increase awareness at the stakeholder level of the importance of oysters beyond commercial fishery values alone.     

The emergence of Cochlodinium along the California Coast (USA)

A sudden and nearly synchronous emergence of the red tide forming dinoflagellate Cochlodinium along more than 800 km of California coastline was initially observed in late summer 2004. Thereafter high cell concentrations have been detected on an annual basis. Here, we present quantitative and semi-quantitative data indicating that Cochlodinium was uncommon in the phytoplankton community in California prior to 2004 and is now persisting as a more regular component and one that seasonally can cause red tides. The quantitative portion of this study was primarily conducted in Monterey Bay, where cell densities reached at least 6 × 10⁴ cells L⁻¹ during the initial outbreak. A semi-quantitative comparison of California coastal counties by the California Department of Health Services (CDHS) was also made: of the 15 counties surveyed (most with multiple sites per county), cells were detected only from Los Angeles County in the south to San Mateo County in the central region (seven counties), but not in the northern part of the state (six counties). Two counties in the central region of the state, San Luis Obispo and Santa Cruz, displayed intense and frequent periods of elevated Cochlodinium cell abundances. Although not observed in the state-wide CDHS survey, we occasionally found cells in San Diego County with densities up to 2.7 × 10⁴ cells L⁻¹. Though these colonial dinoflagellates have been recognized in California for over 80 years, with several “blooms” recorded prior to 2004, the species’ geographic range and abundance in recent years suggest significant shifts in the nearshore phytoplankton community of this region of the eastern Pacific.     

New Insights on the Wall Structure of the Albian-Cenomanian (Cretaceous) Agglutinated Foraminiferal Species Sculptobaculitesgoodlandensis (Cushman et Alexander, 1930) from North-Central Texas,USA

Paleontological Journal - The agglutinated foraminiferal species Sculptobaculitesgoodlandensis has been studied to determine the composition of the cement and grains that make up the test wall....     

Two New Proschizorhynchus Species from the Coast of Massachusetts, USA (Turbellaria, Kalyptorhynchia)1

Proschizorhynchus nahantensis sp. n. and Proschizorhynchus papillatus sp. n. are described and their taxonomy discussed. P. nahantensis is characterized by its penis papilla which has a proximal spherical and distal tubular portion. A simple stylet is present. The female system is distinguished by the external opening of the vagina and the prominent bursal mouthpiece. P. papillatus is distinguished by the two muscle layers of the copulatory organ, the large straight stylet in the penis papilla, a single gonopore and uterus. Notes on the ecology of the species are included. Views are given on the taxonomy of the genus Proschizorhynchus Meixner, 1928.     

Fortuitous Encounters between Seagliders and Adult Female Northern Fur Seals (Callorhinus ursinus) off the Washington (USA) Coast: Upper Ocean Variability and Links to Top Predator Behavior

Behavioral responses by top marine predators to oceanographic features such as eddies, river plumes, storms, and coastal topography suggest that biophysical interactions in these zones affect predators'' prey, foraging behaviors, and potentially fitness. However, examining these pathways is challenged by the obstacles inherent in obtaining simultaneous observations of surface and subsurface environmental fields and predator behavior. In this study, migratory movements and, in some cases, diving behavior of 40 adult female northern fur seals (NFS; Callorhinus ursinus) were quantified across their range and compared to remotely-sensed environmental data in the Gulf of Alaska and California Current ecosystems, with a particular focus off the coast of Washington State (USA) – a known foraging ground for adult female NFS and where autonomous glider sampling allowed opportunistic comparison of seal behavior to subsurface biophysical measurements. The results show that in these ecosystems, adult female habitat utilization was concentrated near prominent coastal topographic, riverine, or inlet features and within 200 km of the continental shelf break. Seal dive depths, in most ecosystems, were moderated by surface light level (solar or lunar), mirroring known behaviors of diel vertically-migrating prey. However, seal dives differed in the California Current ecosystem due to a shift to more daytime diving concentrated at or below the surface mixed layer base. Seal movement models indicate behavioral responses to season, ecosystem, and surface wind speeds; individuals also responded to mesoscale eddies, jets, and the Columbia River plume. Foraging within small scale surface features is consistent with utilization of the inner coastal transition zone and habitats near coastal capes, which are known eddy and filament generation sites. These results contribute to our knowledge of NFS migratory patterns by demonstrating surface and subsurface behavioral responses to a spatially and temporally dynamic ocean environment, thus reflecting its influence on associated NFS prey species.