نتایج جستجو برای: mallard duck
تعداد نتایج: 5348 فیلتر نتایج به سال:
Melanomas are malignant neoplasms originating from melanocytes. They reported in birds. In this case, macroscopic and microscopic (the histopathologic and IHC) findings supported a final diagnosis of cutaneous malignant melanoma in a mallard duck (Anas platyrhynchos). A female mallard duck (Anas platyrhynchos) was observed with a mass on the ventral portion of the neck. Th...
•One of the more well-known examples of hybridization in birds is the frequently documented occurrence between sexually dimorphic Mallards (Anas platyrhynchos) and several closely related nondimorphic species in the mallard complex. In New Zealand, the Grey Duck (Anas superciliosa superciliosa) is the indigenous, nondimorphic Mallardlike species, and extensive hybridization with introduced Mall...
Through the use of data compiled by the Audubon Society's annual Christmas Counts, an attempt has been made to trace the distributional changes of wintering Mallards and Black Ducks in the eastern states from 1900 to the present. During this period the Black Duck has increased relative to the Mallard in few if any states (the Great Lakes region), whereas the Mallard has increased nearly everywh...
Macroscopic sarcocysts are often observed in ducks, but at present their taxonomic status remains uncertain because ducks serve as intermediate hosts for several such parasites in the genus Sarcocystis . One such species, Sarcocystis rileyi , was long ago established to involve the northern shoveler duck ( Anas clypeata ) and the striped skunk ( Mephitis mephitis ) as its intermediate and defin...
We report here the first full-genome sequence of an avian paramyxovirus type 4 (APMV-4) strain isolated from a domestic mallard duck at a live bird market in South Korea. Phylogenetic analyses provide genetic information on a new genetic clade, APMV-4, isolated from a domestic duck and evidence of APMV-4 exchange between poultry and wild birds.
—The relationships between wetland water conditions and breeding numbers of Mallard ( Anas platyrhynchos ), Northern Pintail ( A. acuta ), Blue-winged Teal ( A. discors ), and Northern Shoveler ( A. clypeata ) during May of 1992-1995, were examined on twelve study areas in the eastern Prairie Pothole Region. Data were collected on water levels (by wetland class [temporary, seasonal, semipermane...
We assayed restriction site differences in mitochondrial DNA (mtDNA) within and among allopatric populations of the Mallard (Anas platyrhynchos) and the American Black Duck (A. rubripes). The observed mtDNA clones grouped into two phylogenetically distinct arrays that we estimate differ by about 0.8% in nucleotide sequence. Genotypes in one clonal array were present in both species, while genot...
Regular counts of wintering waterfowl have been undertaken as a part of the International Waterfowl Census (IWC) and the National Swedish Environmental Monitoring Program since 1964. After the first years, a network of annually surveyed sites was established for the calculation of annual indices. Country-wide surveys (also including aerial counts) were undertaken 19711974, 19871989, 19921993...
BACKGROUND Mallard ducks and other waterfowl represent the most important reservoirs of low pathogenic avian influenza viruses (LPAIV). In addition, mallards are the most abundant duck species in Eurasia that migrate over long distances. Despite extended wild bird monitoring studies over the past decade in many Eurasian countries and investigating hundreds of thousands of wild bird samples, no ...
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