Estimating movement rates between Eurasian and North American birds that are vectors of avian influenza (AI)

Avian influenza (AI) is an emerging zoonotic disease that will likely be involved in future pandemics. Because waterbird movements are difficult to quantify, determining the host-specific risk of Eurasian-origin AI movements into North America is challenging. We estimated relative rates of movements, based on long-term evolutionary averages of gene flow, between Eurasian and North American waterbird populations to obtain bidirectional baseline rates of the intercontinental movements of these AI hosts. We used population genomics and coalescent-based demographic models to obtain these gene-flow-based movement estimates. Inferred rates of movement between these populations varies greatly among species. Within dabbling ducks, gene flow, relative to effective population size, varies from ~3-24 individuals/generation between Eurasian and American wigeons (Mareca penelope — M. americana) to ~100-300 individuals/generation between continental populations of northern pintails (Anas acuta). These are evolutionary long-term averages and provide a solid foundation for understanding the relative risks of each of these host species in potential intercontinental AI movements. We scale these values to census size for evaluation in that context. In addition to being AI hosts, many of these species are also important in the subsistence diets of Alaskans, increasing the risk of direct bird-to-human exposure to Eurasian-origin AI virus. We contrast species-specific rates of intercontinental movements with the importance of each species in Alaskan diets to understand the relative risk of these taxa to humans. Greater scaup (Aythya marila), mallard (Anas platyrhynchos), and northern pintail (Anas acuta) were the top three species presenting the highest risks for intercontinental AI movement both within the natural system and through exposure to subsistence hunters. These directly comparable, species-based intercontinental movement rates and relative risk rankings should help in modeling, monitoring, and mitigating the impacts of intercontinental host and AI movements.

Seasonal nutrition variability and trophic differentiation of ducks on Baikal

The analysis of the food ration of 7 species of ducks from Lake Baikal helped to reveal the features of the seasonal dynamics of ducks feeding. The degree of trophic differentiation was determined for all species and for systematically related forms. All species of ducks in general are polyphages of different ranges, there are no highly specialized species. According to the ratio of plant and animal feed, three trophic groups were identified among ducks: phytophages, mainly phytophages and zoo-phytophages. Ducks plant feed is represented by seeds, vegetative parts and tubers. At the same time, a significant proportion are seeds, especially sedge, which in some species of ducks (Anas platyrhynchos, Anas penelopе, Anas acuta) in some seasons exceed 1520% by volume in the stomach and esophagus. Anas querquedula and Anas clypeata ignore vegetative parts of plants, while mallard consumes them only in summer. Anas penelope selects vegetatic parts of plants and seeds, in spring they are selected by Anas acuta. Animal feed is actively consumed by Anas crecca, Anas querquedula, Anas clypeata, Aythya ferina. It is noted that Anas clypeata consumes mollusks in large numbers, while Aythya fuligula consumes them to a slightly lesser extent. Anas querquedula and Anas clypeata prefer insect larvae. Gammarids are quite common for most species of ducks and in volume they occupy a worthy place. Seasonal nutrition dynamics are well traced for all types of ducks. Ducks prefer to use accessible objects, while showing species selectivity in the choice of feed components and feed biotopes. As a result, we see a low overlap of trophic niches of various types of ducks, including systematically close forms.

The Genome Sequence of an H6N5 Influenza A Virus Strain Isolated from a Northern Pintail (Anas acuta) Sampled in Alaska, USA, Shares High Identity with That of a South Korean Wild Bird Strain

ABSTRACT We report the genome sequence of an H6N5 influenza A virus isolated from a northern pintail sampled in Alaska in 2017. All segment sequences shared >99% nucleotide identity with those of a wild bird strain from South Korea. This finding supports viral dispersal between East Asia and North America by wild birds.

ДИНАМИКА НАСЕЛЕНИЯ ПТИЦ КРЫМА ПОД ВЛИЯНИЕМ ГИДРОМЕЛИОРАЦИИ. СООБЩЕНИЕ 1. ЛИМАННО-ОСТРОВНОЙ КОМПЛЕКС, "Наука Юга России"

Представлены результаты анализа влияния гидромелиорации на 28 гнездящихся видов птиц лиманно-островного комплекса лимнофилов. Коренные преобразования фауны и населения птиц равнинного Крыма произошли во второй половине XX века в процессе формирования ирригационной сети Северо-Крымского канала. Восемь видов увеличили численность и область распространения в Крыму, из которых пять (Phalacrocorax carbo, Pehcanus onocrotalus, Ciconia ciconia, Numenius arquata, Remis pandelinus) появились на гнездовании. Смена гидрологического режима слабо отразилась на популяциях четырех малочисленных видов уток (Anas acuta, A. strepera, A. clypeata, Mergus serrator) и трех эвритопных видов куликов (Vanellus vanellus, Charadrius dubius, Haematopus ostralegus). Водохозяйственная деятельность привела к исчезновению колоний Limosa limosa и резкому сокращению гнездовой численности Motacilla feldegg. Переувлажнение прибрежных солончаков стало причиной уменьшения численности Charadrius alexandrinus. Трансформация околоводных биотопов вследствие ирригации незначительно повлияла на численность и распределение колоний чайковых ихтиофагов, тогда как динамика численности и распределение других трофических групп этой систематической группы определялись кормовыми условиями окружающих аквально-территориальных комплексов, ходом сукцессионных смен растительности, а также расширением площади островных систем, образовавшихся в результате затопления балочных понижений мезорельефа.