Whooper Swans Cygnus Research Articles

Extrinsic factors, endocrine mechanisms, and behavioral indicators of migratory restlessness in wintering whooper swans (Cygnus cygnus)

Extrinsic factors, endocrine mechanisms, and behavioral indicators of migratory restlessness were studied in wintering whooper swans (Cygnus cygnus) in the Sanmenxia Swan National Wetland Park in western Henan Province, central China. First, the fecal glucocorticoid metabolite (FGM) concentration was established and related to mean air temperature or photo period (day length) using simple linear or non-linear regression models. After a model selection procedure, the best fitted model revealed that an increase of FGM concentration was associated with an increase in the squared mean air temperature (R2 = 0.88). Other models showed an increasing FGM concentration to correspond with increasing values of day length, squared day length, and mean air temperature—however without statistical support. In a second step, behavioral frequencies of seven behaviors were condensed into three behavioral principal components (PCs) using principal components analysis. Behavioral PCs largely corresponded to three activity phases described for wintering whooper swans in central China and were correlated with the FGM concentration using Spearman's rank-order correlations. Results revealed a significant correlation between FGM and behavioral PC2 (positive factor loadings from vigilance and preening, negative loading from foraging). Finally, we tested for an effect of behavioral PCs on changes in winter home range size using a set of multiple linear regression models. Results of averaged model parameter estimates showed only the behavioral PC3 (positive factor loadings from fighting and calling, negative loading from locomotion) had a marginal significant effect on home range size. Results confirmed findings of previous studies on migratory restlessness in whooper swans. However, due to the small sample size (N = 15 weeks) the effect of PC3 on home range size was weak and should be viewed with caution.

First detection of Enterocytozoon bieneusi in whooper swans (Cygnus cygnus) in China

BackgroundEnterocytozoon bieneusi is a parasite that infects humans and a wide range of other animals. The large migratory waterfowl, the whooper swan (Cygnus cygnus), travels through many cities during its migration and can spread parasites. Despite receiving increasing attention worldwide, there have been no reports of E. bieneusi infection occurring in C. cygnus. Therefore, this study aims to assess the prevalence and genetic characteristics of E. bieneusi in C. cygnus in Sanmenxia, China.MethodsAltogether, 467 fresh fecal samples were collected in the Swan Wetland Park in Sanmenxia, China. Genomic DNA was extracted from fresh fecal samples (n = 467) and E. bieneusi was identified by nested PCR amplification of the internal transcribed spacer (ITS) region. ITS-positive sequences were aligned and phylogenetically analyzed to determine the genotypes of E. bieneusi.ResultsThe overall prevalence of E. bieneusi in C. cygnus was 7.49% (35/467). Sequencing of the 35 positive samples revealed eight known genotypes (EbpA, EbpC, Henan-III, Henan-IV, BEB6, CD9, Peru6 and PtEb IX) and three novel genotypes (CSW1, CSW2 and CSW3). The phylogenetic tree constructed from the ITS sequences showed that seven genotypes (Peru6, EbpA, EbpC, Henan-III, CSW3, Henan-IV and CSW1) clustered within the zoonotic Group 1 while the remaining novel genotype CSW2 clustered within Group 5.ConclusionsTo our knowledge, this is the first report of E. bieneusi in C. cygnus. Of public health significance, our results suggest that migratory C. cygnus might play an important role in the water-borne transmission of E. bieneusi. Effective strategies will be necessary to control E. bieneusi infection in C. cygnus, other animals and humans.

Morphological and phylogenetical analysis reveals that a new tapeworm species (Cestoda: Hymenolepididae) from whooper swan belongs to Cloacotaenia not Hymenolepis

During a helminthological study of waterfowl in China, a new species (Cloacotaenia cygnimorbus sp. nov.) of hymenolepidid cestodes (tapeworm) was found in the small intestine of whooper swan (Cygnus cygnus, Linnaeus, 1758). The rudimentary rostellum and four unarmed muscular suckers, proglottids with distinct craspedote and three spherical testes were coincident with the characters of Cloacotaenia or Hymenolepis, but phylogenetic analysis of 28S rRNA and cox1 gene revealed that the new species is Cloacotaenia rather than Hymenolepis. Its morphology was also clearly differentiated from C. megalops in the arrangement of its testes in a triangle instead of in line and the cirrus unarmed rather than spined. Compared with C. megalops, the new species has more elongated neck, much larger mature proglottids and much smaller testes, cirrus sac, ovary, vitellarium and uterine proglottid. In addition, it infected the host intestine not the cloacae. Phylogenetic analysis of cox1 gene of the new species shows that it had a level of sequence variation (10.52–23.06%) with the sequences of C. megalops. The considerable morphological and molecular differences between those two parasites support C. cygnimorbus sp. nov. as a new species.

Identification of Two novel reassortant avian influenza a (H5N6) viruses in whooper swans in Korea, 2016

BackgroundOn November 20, 2016 two novel strains of H5N6 highly pathogenic avian influenza virus (HPAIVs) were isolated from three whooper swans (Cygnus cygnus) at Gangjin Bay in South Jeolla province, South Korea. Identification of HPAIVs in wild birds is significant as there is a potential risk of transmission of these viruses to poultry and humans.ResultsPhylogenetic analysis revealed that Gangjin H5N6 viruses classified into Asian H5 clade 2.3.4.4 lineage and were distinguishable from H5N8 and H5N1 HPAIVs previously isolated in Korea. With the exception of the polymerase acidic (PA) gene, the viruses were most closely related to A/duck/Guangdong/01.01SZSGXJK005-Y/2016 (H5N6) (98.90 ~ 99.74%). The PA genes of the two novel Gangjin H5N6 viruses were most closely related to AIV isolates previously characterized from Korea, A/hooded crane/Korea/1176/2016 (H1N1) (99.16%) and A/environment/Korea/W133/2006 (H7N7) (98.65%). The lack of more recent viruses to A/environment/Korea/W133/2006 (H7N7) indicates the need for analysis of recent wild bird AIVs isolated in Korea because they might provide further clues as to the origin of these novel reassortant H5N6 viruses.ConclusionsAlthough research on the origins and epidemiology of these infections is ongoing, the most likely route of infection for the whooper swans was through direct or indirect contact with reassortant viruses shed by migratory wild birds in Korea. As H5N6 HPAIVs can potentially be transmitted to poultry and humans, continuous monitoring of AIVs among wild birds will help to mitigate this risk.

Monitoring potential geographical distribution of four wild bird species in China

The outbreak of highly pathogenic avian influenza (HPAI) of the H5N1 subtypes in wild birds and poultry have caught worldwide attention. To explore the association between wild bird migration and avian influenza virus transmission, we monitored potential geographical distribution of four wild bird species that might carry the avian influenza viruses in China. They are bar-headed geese (Anser indicus), ruddy shelducks (Tadorna ferruginea), whooper swans (Cygnus cygnus) and black-headed gulls (Larus ridibundus). They served as major reservoir of the avian influenza viruses. We used bird watching records with the precise latitude/longitude coordinates from January 2002 to August 2014, and environmental variables with a pixel resolution of 5 km × 5 km from 2002 to 2014. The study utilized maximum entropy (MaxEnt) model based on ecological niche model approaches, and got the following results: (1) MaxEnt model have good discriminatory ability with the area under the curve (AUC) of the receiver operating curve (ROC) of 0.86–0.97; (2) the four wild bird species were estimated to concentrate in the North China Plain, the middle and lower region of the Yangtze River, Qinghai Lake, Tianshan Mountain and Tarim Basin, part of Tibet Plateau, and Hengduan Mountains; (3) radiation and temperature were found to provide the most significant information. Our findings will help to understand the spread of avian influenza viruses by wild bird migration in China, which benefits for effective monitoring strategies and prevention measures.

Observations on a hybrid between the whooper swan (Cygnus cygnus) and the mute swan (Cygnus olor)

The swan obtained by hybridization between Cygnus cygnus and C.olor was delivered to the Moscow Zoo from the Leningrad Zoo in 1989. Between 2002 and 2004, it permanently remained with a female whooper swan in a large pond. The two swans behaved as a breeding pair, although the sex of the hybrid bird remained unknown. We observed no courtship displays addressed by the hybrid swan either to the female whooper swan or to other swans living in the pond. The hybrid swan was exteriorly closer to C. cygnus rather than to C. olor and showed increased aggressiveness. Its threatening behavior was intermediate between parental species in terms of threat displays and motor activity, although behavioral patterns characteristic of C.olor prevailed. The most frequent sounds in the vocal repertoire of the hybrid swan were close to the vibrant throbbing call of C.olor in terms of duration and frequency range. In contrast to these sounds, the call of the hybrid swan was noiselike, with distinct harmonic structure (as in the whooper swan except for extremely narrow interharmonic intervals). These vocal signals of the hybrid swan were shown to be intermediate between those of the parental species. In addition, the acoustic repertoire of the hybrid swan included rarely emitted sounds closely resembling elements of vocalizations of both C. cygnus and C. olor.

Pathogenesis of Venous Hypertrophy Associated with Schistosomiasis in Whooper Swans (Cygnus cygnus) in Japan

Thirteen whooper swans (Cygnus cygnus) affected with schistosomiasis were examined pathologically. Venous hypertrophy, characterized by marked nodular proliferation of medial smooth muscle fibers with frequent obliteration of the vascular lumen, was observed in eight of the 13 whooper swans. Venous hypertrophy was located in the medium-sized veins of the mesentery, the serosa, and the muscular layer of the duodenum, jejunum, ileum, and cecum. In addition, vascular lesions were seen in the capsule and parenchymal interstitia of the liver, spleen, kidney, heart, aorta, air sac, and pleura. In mild lesions, segmental proliferation of medial smooth muscles was observed in the venous medium of the mesentery and serosa. Moderate lesions had a proliferation of smooth muscles in the veins with obliteration of venous lumens. In marked lesions, more severe proliferation of veins extended into the intestinal muscular layers and depressed them. Schistosome parasites were found in the venous lumens of each of the eight whooper swans with vascular lesions. Bile pigments and hemosiderin were observed in the livers of whooper swans. In addition, adult nematodes (Sarconema sp.) were localized in the myocardium of four of the eight whooper swans. The venous hypertrophy may be caused by the proliferation of medial smooth muscle fibers induced by schistosomiasis.

Pathogenesis of Venous Hypertrophy Associated with Schistosomiasis in Whooper Swans (Cygnus cygnus) in Japan

Pathogenesis of Venous Hypertrophy Associated with Schistosomiasis in Whooper Swans (Cygnus cygnus) in Japan

First Breeding Records of Whooper Swan and Brambling in North America at Attu Island, Alaska

We document the first breeding records of Whooper Swan (Cygnus cygnus) and Brambling (Fringilla montifringilla) in Alaska and North America on Attu Island in the Western Aleutians in the spring of 1996. Five cygnets were seen with adults and the nest located, and a territorial pair of Bramblings was observed and a nest with eggs found.

Pathological Study of Lead Poisoning in Whooper Swans (Cygnus cygnus) in Japan

During spring 1989, thirty-three whooper swans (Cygnus cygnus) died at Lake Miyajima in Hokkaido, Japan; 15 were examined. The birds were diagnosed as having subacute lead poisoning due to ingestion of spent lead shot. The main gross findings were bile-stained liver, edematous or gelatinous bone marrow, bile-stained lining with hyperkeratosis and lead pellets in the gizzard, and proventricular impaction. Histopathologically, there was lead-hemolytic jaundice of the liver, hemosiderosis in the liver and spleen, and hypoplasia of the bone marrow with increased numbers of polychromatic erythroblasts. Acid-fast intranuclear inclusion bodies were seen in kidneys of seven swans. Under electron microscopy, inclusion bodies had frayed contours and consisted of high-electron-dense fine granules. The lead concentration of the liver ranged from 5.5 to 44.3 mg/kg wet weight. It was suggested that these changes resulted from excess breakdown of erythrocytes, inhibition of heme synthesis, and impaired erythropoiesis caused by lead shot.

A female "Crested" Whooper Swan Cygnus c. cygnus wintering at Hyoko in Niigata, 1976-77 winter

A particular female Whooper Swan Cygnus c. cygnus, wintering at the well known swan and other waterfowls resort, lake Hyoko, was kept under observation in 1976-77 winter. Here the swans and waterfowls are well tamed by artificial feeding. This particular female arrived at Hyoko in late December with her mate and 2 cygnets. In my first observation in December, her crown seemed to be somewhat unkempt, but it was not so curious.As the time went by her crown feathers became longer. This changing process is shown by Plates 13-16.

The Ecology of Closely Related Species with Special Reference to Cormorant (Phalacrocorax carbo) and Shag (P. aristotelis)

This paper is a sequel to one on the ecological aspects of species formation in passerine birds (Lack, I944). Gause (I934) contends that two species with similar ecology cannot live in the same area, and in the earlier paper this principle was shown to hold among closely related species of passerine birds, both in Britain and on oceanic islands. Such species either frequent different regions, or different habitats, or, when they live in the same place, they eat mainly different foods, the latter commonly being associated with a difference in body size. I originally intended to follow this paper with a second one analysing the extent to which the same might apply in British non-passerine birds. Among these birds, examples of closely related species which breed in a similar habitat but in mainly different regions are provided by the mute and whooper swans (Cygnus olor and C. cygnus), the curlew and whimbrel (Numenius arquata and N. phaeopus), and the common and arctic terns (Sterna hirundo and S. macrura). In each of these pairs, the first-mentioned species breeds mainly south of the second. Examples of related species which breed in the same regions but in mainly different habitats include: the long-eared owl Asio otus in woods and the short-eared owl A. flammeus in open country; the marsh harrier Circus aeruginosus in very damp marshland and the Montagu harrier C. pygargus in dryer marshland and on heaths; the goosander Mergus merganser primarily by swiftflowing streams and the red-breasted merganser M. serrator primarily by Iochs. Two species which Qverlap widely in both region and habitat but differ in food are the hobby Falco subbuteo and kestrel F. tinnunculus. Both frequent open country with trees in southern England, but the hobby feeds primarily on insects and on small birds caught on the wing, and the kestrel primarily on rodents and to a much smaller extent on small birds and insects caught on the ground. A case of a difference in both habitat and food is provided by the four species of gallinaceous birds in northern Scotland, of which the ptarmigan (Lagopus mutus) lives in the alpine zone feeding primarily on Empetrum and Vaccinium, the red grouse (Lagopus scoticus) on moorland feeding primarily on Calluna, the blackcock (Lyrurus tetrix) on the wood edge feeding primarily on Betula, and the capercaillie (Tetrao urogallus) in forest feeding primarily on Pinus needles. (Though the two latter species are placed in separate genera from the two former, they are probably closely related. In making generic distinctions, undue weight would seem to have been given to male characters. The females of the four species are rather similar in appearance, while interbreeding has been recorded not infrequently.) In the earlier paper, instances were also given in which two related passerine species frequent the same habitat, but differ markedly in body-size and in food. British non-passerine birds probably provide several further examples, but in most cases insufficient is known of the food of the birds concerned to say whether or not the size difference is correlated with a difference in diet. Examples are the great and lesser spotted woodpeckers (Dryobates major and D. minor), mallatd and teal (Anas platyrhynchos and A. crecca), great-crested and little grebe (Podiceps cristatus and P. ruficollis), little, common and sandwich terns (Sterna albifrons, S. hirundo and S. sandvicensis), and several species of gulls (Larus spp.). The idea of a complete survey of Brltish nonpasserine birds was eventually -abandoned owing to the many cases in which two closely related species appear to overlap widely in ecology, but insufficient is known to state definitely whether or not this is the case. From the information available in general works on British birds, notably Witherby (1938-41), the following species appear to come in this category: tawny and long-eared owls (Strix aluco and Asio otus), both living in woods and eating similar prey; teal and garganey (Anas crecca and A. querquedula) on southern marshes and inland waters; gadwall, wigeon and pintail (Anas strepera, A. penelope and A. acuta) on northern waters; and among sea birds, cormorant and shag (Phalacrocorax carbo and P. aristotelis), storm and fork-tailed petrels (Hydrobates pelagicus and Oceanodroma leucorrhoa), roseate and common terns (Sterna dougallii and S. hirundo) and herring and lesser black-backed gulls (Larus argentatus and L. fuscus).