Netta Peposaca Research Articles

Systematics and life cycles of four avian schistosomatids from Southern Cone of South America.

Relative to the numerous studies focused on mammalian schistosomes, fewer include avian schistosomatids particularly in the southern hemisphere. This is changing and current research emerging from the Neotropics shows a remarkable diversity of endemic taxa. To contribute to this effort, nine ducks (Spatula cyanoptera, S.versicolor, Netta peposaca), 12 swans (Cygnus melancoryphus) and 1,400 Physa spp. snails from Chile and Argentina were collected for adults and larval schistosomatids, respectively. Isolated schistosomatids were preserved for morphological and molecular analyses (28S and COI genes). Four different schistosomatid taxa were retrieved from birds: Trichobilharzia sp. in N. peposaca and S. cyanoptera that formed a clade; S.cyanoptera and S. versicolor hosted Trichobilharzia querquedulae; Cygnus melancoryphus hosted the nasal schistosomatid, Nasusbilharzia melancorhypha; and one visceral, Schistosomatidae gen. sp., which formed a clade with furcocercariae from Argentina and Chile from previous work. Of the physid snails, only one from Argentina had schistosomatid furcocercariae that based on molecular analyses grouped with T. querquedulae. This study represents the first description of adult schistosomatids from Chile as well as the elucidation of the life cycles of N.melancorhypha and T. querquedulae in Chile and Neotropics, respectively. Without well-preserved adults, the putative new genus Schistosomatidae gen. sp. could not be described, but its life cycle involves Chilina spp. and C. melancoryphus. Scanning electron microscopy of T. querquedulae revealed additional, undescribed morphological traits, highlighting its diagnostic importance. Authors stress the need for additional surveys of avian schistosomatids from the Neotropics to better understand their evolutionary history.

Rhinonyssus rhinolethrum (Trouessart, 1895) (Mesostigmata: Rhinonyssidae) in Netta peposaca (Vieillot, 1816) (Anseriformes: Anatidae) from Southern Brazil.

Netta peposaca is an anatid endemic to the South American continent and Rhinonyssus rhinolethrum is a rhinonissid mite of wide geographical distribution parasitizing several species of anatids. The association between these organisms has been reported in Argentina; however, the number of birds examined and the parasite indices have not been reported. Thus, the objective of this study was to know the diversity of nasal mites associated with N. peposaca in southern of Brazil and the parasitological indices. The nasal cavities of 30 birds from two locations in Rio Grande do Sul, Brazil, were examined to collect mites. Rhinonyssus rhinolethrum occurred in 16.67% of the birds with an infection intensity of 3-24 mites/host. Infections in male and female hosts showed no significant differences. This study records for the first time R. rhinolethrum and its infection indices in N. peposaca in the southern of Brazil.

Rare birds in Slovenia in 2015 – Slovenian Rarities Committee’s Report

Summary This report by the Slovenian Rarities Committee presents records of rare bird species in Slovenia in 2015, with some addenda for previous years. The numbers in brackets refer to the number of records (first number) and individuals (second number) recorded between 1 Jan 1950 and 31 Dec 2014. Since 1 Jan 2013, submission to the Committee has been required for 37 additional species, 17 of which are regional rarities. Records of these species are not numbered, since records from previous years were not collected by the Committee. One new species, the Desert Wheatear Oenanthe deserti, was added to category A. Other notable observations were the first record of Parrot Crossbill Loxia pytyopsittacus after 1909, the second record of Baillon’s Crake Zapornia pusilla, the third and fourth records of Calandra Lark Melanocorypha calandra, the fourth of Long-legged Buzzard Buteo rufinus, the fifth of Richard’s Pipit Anthus richardi and the sixth of Grey Phalarope Phalaropus fulicarius. Four species were added to category E: Bahama Pintail Anas bahamensis, Rosy-billed Pochard Netta peposaca, Harris’s Hawk Parabuteo unicinctus and Alexandrine Parakeet Psittacula eupatria. The list of birds recorded in Slovenia (as of 31 Dec 2015) contains 386 species (371 in category A, 6 in category B, 9 exclusively in category C; 4 species are both in categories A and C). Category D contains 6 species, while category E contains 38, two of which are classified into subcategory E*. These two categories are not part of the list.

Composition of the diet of Netta peposaca (Birds: Anseriformes) in Santa Fe province, Argentina

We examined the diet of the Rosy-billed Pochard, Netta peposaca (Vieillot, 1816), (n = 59) during the autumn of 2010 in Santa Fe province, Argentina. Were analyzed a total of 59 ducks (n = 37 females and n = 22 males) to assess their gastrointestinal contents. The trophic spectrum was composed of 16 taxa (plant fraction: animal fraction 9 and 7). The contribution of each food category estimated using the IRI was: Echynochloa sp. (Poaceae) = 4301, Polygonum sp. (Polygonaceae) = 956, and unidentified graminoid species = 53 (females: Echynochloa sp. = 4313, Polygonum sp. = 1095 and males: Echynochloa sp. = 5522, Polygonum sp. = 814). No significant differences were found between females and males in diet composition (Fisher's test, p < 0.05). Moreover, the diversity index (H') was significantly (Mann-Whitney, p < 0.05) different between sexes. The Rosy-billed Pochard showed a predominantly phytophagous feeding habit in autumn. Likewise, this is the first contribution on the sexual differences in the feeding biology of the Rosy-billed Pochard.

Isolation and characterization of an H9N2 influenza virus isolated in Argentina

As part of our ongoing efforts on animal influenza surveillance in Argentina, an H9N2 virus was isolated from a wild aquatic bird (Netta peposaca), A/rosy-billed pochard/Argentina/CIP051-559/2007 (H9N2) – herein referred to as 559/H9N2. Due to the important role that H9N2 viruses play in the ecology of influenza in nature, the 559/H9N2 isolate was characterized molecularly and biologically. Phylogenetic analysis of the HA gene revealed that the 559/H9N2 virus maintained an independent evolutionary pathway and shared a sister-group relationship with North American viruses, suggesting a common ancestor. The rest of the genome segments clustered with viruses from South America. Experimental inoculation of the 559/H9N2 in chickens and quail revealed efficient replication and transmission only in quail. Our results add to the notion of the unique evolutionary trend of avian influenza viruses in South America. Our study increases our understanding of H9N2 viruses in nature and emphasizes the importance of expanding animal influenza surveillance efforts to better define the ecology of influenza viruses at a global scale.

Multiple endocardial neurofibromas in a rosy-billed pochard (Netta peposaca)

Endocardial neoplasms are uncommon in veterinary species with most cases restricted to endocardial schwannomas in aged rats. A 15-year-old male rosy-billed pochard (Netta peposaca) was diagnosed following necropsy with numerous, proliferative endocardial masses. Histologically, these masses were composed of interlacing streams and bundles of neoplastic spindle cells supported by a fine fibrovascular stroma. Rare areas of cellular and nuclear palisading were present in the nodules. Approximately 60% of the neoplastic cells were strongly positive for S-100, whereas none of the neoplastic cells was positive for desmin, synaptophysin, neurofilament, and glial fibrillary acidic protein. The histologic features coupled with the S-100 immunoreactivity led to a diagnosis of endocardial neurofibroma.

Phylogenetic Analysis of H6 Influenza Viruses Isolated from Rosy-Billed Pochards (Netta peposaca) in Argentina Reveals the Presence of Different HA Gene Clusters

Until recently, influenza A viruses from wild waterfowl in South America were rarely isolated and/or characterized. To explore the ecology of influenza A viruses in this region, a long-term surveillance program was established in 2006 for resident and migratory water birds in Argentina. We report the characterization of 5 avian influenza viruses of the H6 hemagglutinin (HA) subtype isolated from rosy-billed pochards (Netta peposaca). Three of these viruses were paired to an N2 NA subtype, while the other two were of the N8 subtype. Genetic and phylogenetic analyses of the internal gene segments revealed a close relationship with influenza viruses from South America, forming a unique clade and supporting the notion of independent evolution from influenza A viruses in other latitudes. The presence of NS alleles A and B was also identified. The HA and NA genes formed unique clades separate from North American and Eurasian viruses, with the exception of the HA gene of one isolate, which was more closely related to the North American lineage, suggesting possible interactions between viruses of North American and South American lineages. Animal studies suggested that these Argentine H6 viruses could replicate and transmit inefficiently in chickens, indicating limited adaptation to poultry. Our results highlight the importance of continued influenza virus surveillance in wild birds of South America, especially considering the unique evolution of these viruses.

NUEVOS DATOS SOBRE TRES ESPECIES DE KOELLIKERIOIDES (DIGENEA, DIDYMOZOIDAE) EN ATÚN DE BRASIL

Cuatro especies de peces escómbridos (Perciformes) de la zona costera de Río de Janeiro, Brasil, fueron examinados para estudiar sus helmintos parásitos: Thunnus albacares (Bonnaterre, 1788), Thunnus atlanticus (Lesson, 1831), Thunnus obesus (Lowe, 1839) y Euthynnus alletteratus (Rafinesque, 1810). Tres especies del género Koellikerioides Yamaguti, 1970: K. apicalis Yamaguti, 1970, K. externogastricus Yamaguti, 1970 y K. intestinalis Yamaguti, 1970, se registraron en las branquiespinas, en la capa muscular externa de la pared del estómago y en la superficie interna del intestino delgado, respectivamente. Se presentan las medidas originales, los parámetros de la infeccióny las ilustraciones originales. K. apicalis y K. intestinalis mostraron el patrón típico de distribución agregada. El análisis estadístico mostro que había una correlación negativa significativa entre la longitud total de E. alletteratus y la prevalencia de K. intestinalis. Los resultados de K. apicalis en T. atlanticus y de K. intestinalis en T. atlanticus y E. alletteratus representan nuevos registros de hospedadores. Todas las especies se reportan por primera vez en el Océano Atlántico Sudoccidental.

Recent and Chronic Exposure of Wild Ducks to Lead in Human-modified Wetlands in Santa Fe Province, Argentina

Poisoning of waterfowl due to ingestion of lead pellets is a worldwide problem in areas that are subject to hunting. No studies have assessed exposure of waterbirds to this heavy metal in Argentina, in spite of intense hunting activity, and the fact that only lead ammunition is commercially available. The objective of this study was to evaluate duck exposure to lead by examining gizzard and bone samples collected from 30 wild ducks, 16 Rosy-billed Pochard (Netta peposaca), and 14 Fulvous Whistling-Duck (Dendrocygna bicolor), provided by hunters in northern Santa Fe Province, Argentina, in July 2007. Radiographs, followed by dissection of the gizzards, showed that 31% of the Rosy-billed Pochards and 29% of the Fulvous Whistling-Ducks had ingested lead pellets (between one and four per animal). Lead in bone was found at concentrations associated with detrimental health effects. In spite of the small number of samples in this project, these results indicate high levels of lead exposure (both recent and chronic) in these species. This is the first report of a problem in Argentina that could represent a threat to the health and conservation of native aquatic species, their predators, and the wetlands they inhabit.

Diploposthe laevis (Bloch) Jacobi (Eucestoda, Hymenolepididae) from Netta peposaca (Vieillot) (Aves: Anatidae): first record for the Neotropical Region and a new host

One hundred eight rosy-billed pochards, Netta peposaca (Vieillot, 1816), collected in Brazil and Argentina were examined for endoparasites. Collection sites included the municipalities of Santa Vitória do Palmar and Jaguarão, Rio Grande do Sul State, Brazil (wintering site) and Alvear, Corrientes Province, northern Argentina (nesting site). Birds were frozen in dry ice after collection. During necropsy they were categorized according to sex and maturation, either adult or juvenile. The cestode Diploposthe laevis (Bloch) Jacobi, 1896 was found (prevalence 68.5%, mean infection was 2). The mean prevalence of D. laevis in Alvear (25.9%) was higher than found in Jaguarão and Santa Vitória do Palmar, Rio Grande do Sul (19%), and could be related to the nesting site and to the period when the birds may ingest a higher amount of food. This is the first record of a species of the genus Diploposthe in anatideans from South America, and the first record of the species in N. peposaca. Details of the cirrus pouch and vagina were described based on histological sections.

Prosthogonimus ovatus (Rudolphi) (Digenea, Prosthogonimidae) em três espécies de aves aquáticas da Região Sul do Brasil

Three species of birds, two anatids, Dendrocygna bicolor (Vieillot, 1816) (Fulvous Whistling Duck) and Netta peposaca (Vieillot, 1816) (Rosy-billed Pochard), and one phalacrocoracid, Phalacrocorax brasilianus (Gmelin, 1789) (Neotropical Cormorant) were collected from several localities in the Coastal Plain Province and in Lago Guaiba, State of Rio Grande do Sul. The number of birds examined of each host species with the respective values of prevalence and mean intensity of infection of P. ovatus were: 33 D. bicolor , 3%, 1 helminth/host; 20 N. peposaca 15%, 4.3 helminths/host, and 47 P. brasilianus 2.1%, 1 helminth/host. The single specimen collected from the Neotropical cormorants and one of the specimens collected from the rosy-billed pochards, were in the cloaca. The remaining specimens from the rosy-billed pochards and the single specimen from the fulvous whistling ducks were in the bursa of Fabricius. This is the first record of P. ovatus in Neotropical cormorants and rosy-billed pochards. The known geographical distribution of P. ovatus is extended to the southernmost State of Brazil, Rio Grande do Sul.

Echinuria uncinata (Rudolphi) (Nematoda, Acuariidae) in Netta peposaca (Vieillot) (Aves, Anatidae) in South America

This is the first report of a species of Echinuria Soloviev, 1912, on anatid hosts in South America, causing granulomas. It is also the first detailed description and record of a species of Echinuria, for South America in the Rosy-billed Pochard, Netta peposaca (Vieillot, 1816). Fifty-two rosy-billed pochards were examined for helminths in the Municipalities of Santa Vitória do Palmar (locality of Fazenda Sossego) and (locality of Ponta da Antena), State of Rio Grande do Sul, Brazil, and Alvear, Province of Corrientes, northern Argentina. Samples were obtained from 2003 to 2004. After the catch each bird was immediately frozen with dry ice. Prior to necropsy birds were sexed, weighted, measured, and the state of maturity (juvenile or adult) determined, based on the presence or absence of a bursa of Fabricius. The granulomas with the nematodes were found in the proximal esophagus at the junction with the proventriculus. Two birds had one (fistulated) and two granulomas, respectively. One of the birds was from the wintering grounds along the coastal region in the State of Rio Grande do Sul, southern Brazil. The other, from one of the breeding grounds in northern Argentina, was captured before the trip to the wintering grounds along the migratory flyway. Prevalence was 3.8% while the mean intensity of infection was 7.2. Morphometry of males and females and the comparison with previous descriptions and illustrations allowed the identification of the present specimens as E. uncinata.

Migration and other movements among the lower Paraná River valley wetlands, Argentina, and the south Brazil/Pantanal wetlands

SummaryThe southern portion of South America plays an important role for the conservation of many waterfowl and waders. Migratory movements were, till recently, known only for Arctic or Patagonian species. The only exception was the Southern Pochard Netta peposaca, with a west—east winter migration from the lower Parana River valley to south Brazil coastal wetlands. The banding studies that have been conducted by the Centro de Pesquisas para a Conservação das Aves Silvestres (CEMAVE/IBAMA) since 1980, directly or through agreements with local organizations, showed more details of this migration, plus indications that other aquatic species such as Chilean Flamingo Phoenicopterus chilensis, other duck species, Neotropic Cormorant Phalacrocorax olivaceus and White-faced Plegadis chihi may follow the same pattern. A migration into the same area the Pantanal population of the Wood Stork Mycteria americana was only recently discovered, and other species may also do likewise when the Pantanal is seasonally flooded. The studies of such bird migration or movements between the main South American wetlands are of great importance to understanding their conservation needs, especially when international cooperation among the countries plays a most important role. The region has been suffering human pressures of various types, from land reclamation for pasture and/or agriculture to the operation, in the last 30 years, of big hydroelectric dams which affect the natural flow of rivers or keep flood-plains under water. The impending construction of the Hidrovia Paranà/Paraguay, a large project for heavy river use as a main transportation route, may represent an enormous impact on such rich aquatic habitats, demanding immediate cooperation among the countries involved to mitigate negative effects on the environment. The impact may be similar to what happened in the Mississippi valley early this century. The west-east movements between the Paranà River valley and south Brazil are of special conservation interest, as a nationally threatened species (in Brazil) is involved (the Chilean Flamingo) as well as duck species targeted for the hunting season in the area.

The Breeding Biology of Captive Black-Headed Ducks and the Behavior of Their Young

The behavior patterns of captive Black-headed Ducks (Heteronetta atricapilla) at the Wildfowl Trust, Slimbridge, Gloucester, were studied for three consecutive breeding seasons to investigate the breeding biology of this parasitic species. The birds fed mostly in the early morning and swam most actively in the evening, while they mainly rested on land during midday. In the evening, both males and females patrolled or skulked near nest sites of other birds, apparently searching for a suitable host to parasitize. The existence of pair-bonds during the breeding season was fully established; copulation and egg-laying were observed. Two Black-headed Duck eggs were returned to the nest of a Rosy-billed Pochard (Netta peposaca) to determine the post-hatching behavior of the young and the role of the host bird. One Black-headed duckling hatched before any of the host's own clutch and left the nest on its own one day after hatching. The second duckling, which hatched with the young pochards, accompanied the family to water and returned to the female for warmth and protection (at increasingly infrequent intervals) for two days. These findings emphasize the uniqueness of the species and reinforce the case for placing Heteronetta in a tribe of its own. The Black-headed Duck (Heteronetta atricapilla) frequents freshwater marshes in the temperate regions of South America, ranging from central Argentina to Bolivia and across the continent from central Chile to southern Brazil. Breeding has been recorded in Argentina, Chile, and central Paraguay (Delacour 1959, Weller 1967, Todd 1979). Since Phillips (1925) first remarked about the lack of information on the Black-headed Duck, studies of its morphology and behavior have revealed its singularity; even its taxonomic position is still disputed. Similarities in anatomy and certain behavior patterns link Heteronetta to the Oxyurini, with whom they are most commonly classified. However, Blackheaded Ducks also exhibit a number of behavioral characteristics of the Anatini, and may be descendants of a primitive group from which both tribes evolved (Weller 1968a). The parasitic breeding behavior of the Blackheaded Duck is considered unique among waterfowl. Several species of Anatidae, most notably Redheads (Aythya americana) and Ruddy Ducks (Oxyurajamaicensis) occasionally lay eggs in other birds' nests (Friedmann 1932), but they usually hatch and rear their own young. The Black-headed Duck, however, neither builds a nest nor incubates its eggs, but leaves these duties entirely to host birds. The female tends to lay during the host's laying period, thereby making full incubation more likely, and usually adds her egg to the host's nest with little or no damage to the main clutch. Black-headed Duck eggs have been found in nests of a wide range of birds, including birds of prey (e.g., Chimango Caracara, Milvago chimango) and gulls (e.g., Common Black-headed Gull, Larus ridibundus). However, the preferred hosts appear to be coots (Fulica rufifrons and F. armillata), probably because their nests are common in marshy areas (Weller 1968a). Although the Black-headed Duck in its natural environment has been studied extensively by Weller (1967, 1968a, b), the species' unobtrusive nature and preferred habitat have made it difficult to observe its breeding behavior and a number of points still require clarification. We describe here the diurnal activities of captive Black-headed Ducks during the breeding season, including their pre-laying and pre-copulatory behavior, as well as the behavior of ducklings that hatched in the nest of a Rosy-billed Pochard (Netta peposaca). MATERIALS AND METHODS In 1974 the Wildfowl Trust collected eggs of Black-headed Ducks in Argentina in order to establish a captive breeding population of this species at Slimbridge, Gloucestershire, England. The five males and two females from