Blood biochemistry reveals malnutrition in black-necked swans (Cygnus melanocoryphus) living in a conservation priority area

The application of clinical biochemical techniques to determine the products of intermediary metabolism has proved to be a reliable approach for the study of the physiological state of animals in nature. More specifically, the determination of plasma metabolites, such as glucose, total proteins (PRO), albumin (ALB), globulins (GL), urea, uric acid, triglycerides (TG) and beta-hydroxy-butyrate (BHB), and plasma enzymes such as creatine kinase (CK) and aspartate aminotransferase (AST) in wild animals is a valuable possibility for a non-destructive assessment of health in endangered populations. Since August 2004 to January 2005, we conducted a temporal study in a conservation priority site, the "Carlos Anwandter Nature Sanctuary" to determine blood biochemistry of a wild population of black-necked swans (Cygnus melanocoryphus). This population was experiencing a drastic reduction, according to the actual knowledge about yearly fluctuations in numbers and breeding pairs. In six months, we periodically sampled about 12 swans (a total of 122 individuals), which exhibited a reduction near 30% in body mass (body mass corrected by total length). Our results showed reductions in most plasma biochemical parameters (glucose, PRO, ALB, uric acid, TG) and increase in BHB, which taken together indicated signs of chronic malnutrition. Also, the increase in AST and CK that we found, together with additional evidences of sub-lethal hepatic damage (in dead individuals), and iron pollution in aquatic plants and water confirmed that water pollution was the ultimate cause of this population reduction.     

Zinc toxicosis in a free-flying trumpeter swan (Cygnus buccinator)

A trumpeter swan (Cygnus buccinator) was observed near a mill pond in Picher, Oklahoma, USA. It became weakened and emaciated after about 1 mo, was captured with little resistance, and taken into captivity for medical care. Serum chemistry results were consistent with hepatic, renal, and muscular damage. Serum zinc concentration was elevated at 11.2 parts per million (ppm). The swan was treated for suspected heavy-metal poisoning, but died overnight. Gross postmortem findings were emaciation and pectoral muscle atrophy. Histopathologic lesions in the pancreas included mild diffuse disruption of acinar architecture, severe diffuse depletion or absence of zymogen granules, occasional apoptotic bodies in acinar epithelial cells, and mild interstitial and capsular fibrosis. Zinc concentration in pancreas was 3,200 ppm wet weight, and was similar to that reported in the pancreases of waterfowl known to be killed by zinc toxicity. Zinc concentrations in liver (154 ppm) and kidneys (145 ppm) also were elevated. Acute tubular necrosis of the collecting tubules of the kidneys was also possibly due to zinc toxicity. To the authors' knowledge, this is the first confirmed case of zinc poisoning in a trumpeter swan associated with mining wastes.     

Actinobacillus septicemia in a black swan (Cygnus atratus).

A species of Actinobacillus was isolated in pure culture from the carcass of a captive Australian black swan (Cygnus atratus) dying of acute septicemia. The gross and microscopic findings are described and the significance of the isolate is discussed.     

Characterization of microsatellite loci isolated in trumpeter swan (Cygnus buccinator)

Primers for 16 microsatellite loci were developed for the trumpeter swan (Cygnus buccinator), a species recovering from a recent population bottleneck. In a screen of 158 individuals, the 16 loci were found to have levels of variability ranging from two to seven alleles. No loci were found to be linked, although two loci repeatedly revealed significant departures from Hardy–Weinberg equilibrium. Amplification in the closely related tundra swan (Cygnus columbianus) was successful for all except one locus. These microsatellite loci will be applicable for population genetic analyses and ultimately aid in management efforts.     

Complete mitochondrial genome of the Bewick's swan Cygnus columbianus bewickii (Aves, Anseriformes, Anatidae)

The mitochondrial genome of Bewick's swan Cygnus columbianus bewickii was completely sequenced and then the resultant data were compared with those of the whistling swan Cygnus columbianus columbianus. The complete mitochondrial genome sequence of C. c. bewickii was 16,727?bp in length and its gene arrangement pattern, gene content, and genome organization were identical to those of Cygnus species. The similarities of nucleotide and amino acid sequences between the two swans were 99.1% and 99.6%, respectively. Out of the 13 protein-coding genes and 2 rRNA genes, COIII showed the lowest nucleotide sequence similarity with 98.0%. On the other hand, in amino acid sequence similarities, both COII and ATP6 showed the lowest with 98.7% in common. The control region has the 97.8% nucleotide sequence similarity.     

Macrophages,a normal component in seasonally involuting testes of the swan,Cygnus olor

Summary In the swan, Cygnus olor, spermatogenesis shows a pronounced seasonal cycle. During the long involution phase a transient invasion of macrophages into the seminiferous tubules regularly takes place at the height of regression prior to total rest. These macrophages are involved in the additional disposal of supernumerary and degenerating premature germ cells, at a time when the Sertoli cells are already filled with phagolysosomes.     

Microsatellite loci for paternity assessment in the black swan (Cygnus atratus: Aves)

Seven polymorphic tetranucleotide microsatellite loci were isolated and characterized from the black swan Cygnus atratus Latham, using nonradioactive PCR‐based techniques to screen an enriched genomic library. These loci were highly variable (mean H _E  = 0.75, mean number of alleles = 9.1), and showed no evidence of linkage disequilibrium or null alleles. This locus set is suitable for detecting extra‐pair copulations (combined exclusion probability = 0.999) and for other population genetic applications.     

荣成大天鹅自然保护区泻湖湿地植物区系

在2004—2007年每年的7—9月4次实地调查及参考相关资料基础上,分析了山东荣成大天鹅自然保护区湿地植物区系的特征。区系中有单细胞浮游藻类59属192种,底栖多细胞大型海藻58属74种,维管束植物55科134属194种。区系中的单细胞浮游藻类包括近岸广布种116种、近岸暖水种31种、近岸温带种26种;维管束植物被划分为6大生态类群,包括盐生植物24种、水生植物22种、湿生植物35种、中生植物103种、旱生植物6种、沙生植物4种,保护区内湿地植被的建群种、优势种均为水生植物、湿生植物或盐生植物,反映了湿地植被的隐域性;维管束植物按照生活型划分,有20种高位芽植物、4种地上芽植物、54种地面芽植物、48种地下芽植物和68种1年生植物,其中地面芽植物、地下芽植物占区系植物总种数的比例较高,占52.58%,反映冷湿气候和局部低洼积水环境对区系的形成起较重要作用。维管束植物属有14个地理分布区类型,包括世界分布属42属、温带分布属55属、热带分布属30属、古地中海属2属、东亚分布属4属、中国特有分布属1属,其中世界分布属和温带分布属分别占区系维管束植物总属数的比例较高,分别为31.34%和41.04%,反映了湿地植被的隐域性和冷湿气候对湿地植被发育、分布的影响。     

Observations on a hybrid between the whooper swan (<Emphasis Type=Italic>Cygnus cygnus</Emphasis>) and the mute swan (<Emphasis Type=Italic>Cygnus olor</Emphasis>)

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.     

Extra-pair paternity does not result in differential sexual selection in the mutually ornamented black swan (Cygnus atratus)

We studied patterns of parentage in 85 broods (332 cygnets) of black swans during three breeding seasons, using a set of eight polymorphic microsatellite markers. We detected both intraspecific brood parasitism (IBP; < 5% of cygnets per year) and extra-pair paternity (EPP). In these years, 10-17% (mean = 15.1%) of cygnets resulted from EPP, and 27-40% (mean 37.6%) of broods contained at least one extra-pair cygnet. Compared with levels of EPP in closely related species with similar life histories, these values are unexpectedly high. EPP in black swans appears unrelated to ecological factors (breeding density and synchrony) or genetic factors (genetic similarity between pair members or genetic quality of the offspring). We found no evidence that a mutual sexual feather ornament known to play a role in social mate choice in black swans (curled wing feathers) is involved in extra-pair mate choice. EPP does not lead to greater variance in reproductive success in males, relative to females in this species. We therefore suggest that EPP does not result in differential sexual selection on males and females, explaining why they are ornamented to the same degree.     

Eutrophication and black swan (Cygnus atratus Latham) populations: tests of two simple relationships

In an earlier study, regression models were developed which related black swan populations to macrophyte biomass and to phytoplankton productivity in Tomahawk Lagoon No 2, a small South Island, New Zealand, lake in which phytoplankton and macrophytes vary widely from year to year, in an irregular inverse cycle. Two years of further study confirmed that winter swan populations are directly correlated with macrophytes, for samples taken on a single day in winter each year. They also confirmed that winter maximum swan populations can be predicted from measurements of phytoplankton productivity in the previous summer. This relationship is inverse. For 6 other lakes, 9 of the 11 data points lay within the 95% confidence intervals of the macrophyte-swan relationship, with the only outlier being a lake in which the macrophytic vegetation is dominated by filamentous algae. Further analysis, giving equal weight to each of the 7 lakes in the sample, confirmed that there is a significant correlation in winter between swan populations and macrophyte biomass for these lakes which show a wide range of size and trophic status. There was no such significant correlation in summer. All of the 8 data points from 7 other lakes lay within the rather broad 95% confidence intervals of the phytoplankton- swan relationship. The 4 lakes which fitted most closely to the predictions of this relationship have silty sediment. The other 3, which all had lower swan populations than predicted, have sediment predominantly of sand or fine clay, and macrophyte biomass and swan populations may be constrained by the nature of the sediment, rather than by shading effects from phytoplankton.     

Causes of mortality in the Mute swan Cygnus olor on the River Thames

Over the last 20 years there has been an unprecedented decline of the Mute swan on the River Thames. Between August 1979 and October 1981 a systematic attempt was made to collect as many swan corpses as possible. Of 94 swan corpses examined at post-mortem 57% died from lead poisoning due to ingestion of anglers' weights. Birds dying from lead poisoning had significantly higher liver and kidney lead levels. Kidney proved to be the most useful indicator tissue, the median lead level in birds with lead weights in their gizzard was 908 μg/g DM compared to 8 μg/g DM in birds without weights. More immature birds die from lead poisoning than other factors and significantly more corpses were found between the months of July-October.
Ultra-structure examinations revealed electron dense intra-nuclear inclusions in the cells of proximal convulated tubules of the kidney and X-ray analysis confirmed that these structures consisted of lead.     

Three-dimensional structure of goose-type lysozyme from the egg white of the Australian black swan, Cygnus atratus

The egg white of C. atratus contains two forms of lysozyme, a 'chick-type' which is similar to that found in the egg white of the domestic hen, and a 'goose-type' similar to that found in the egg white of the Embden goose. The molecular structure of the goose-type lysozyme has been determined at a resolution of a 2.8 A by X-ray crystallographic analysis. The structure consists of two domains linked by a long stretch of alpha-helix. In all, there are seven helical segments in the structure. While there is no amino acid sequence homology with either hen egg-white or bacteriophage T4 lysozymes, there are portions of the structure where the folding of the main chain is similar to that found in portions of either hen egg-white lysozyme or T4 lysozyme or both. In particular, there is a consistency of structure in the arrangement of acid groups in the catalytic site. G-o plots calculated for this structure and for the bacteriophage T4 lysozyme structure show that both have similar 'modules' of structure with boundaries occurring at structurally equivalent positions. Three of the common boundaries are equivalent structurally to three of the four module boundaries observed in G-o plots of hen egg-white lysozyme. The variation in the position of the remaining boundary may be related to differences in substrate binding.     

Oxygen consumption and thermoregulatory responses in three species of South American marsupials

Oxygen consumption (VO(2)), body temperature (T(b)) and wet thermal conductance (C(wet)), under resting conditions, exposure to low ambient temperature (T(a)) and during sustained exercise (treadmill running) were measured in three phylogenetic related (same family; Didelphidae) South American marsupials possessing similar body masses: Caluromys philander (arboreal/fruit and insect eating), Philander opossum (terrestrial and arboreal/omnivore), and Metachirus nudicaudatus (terrestrial/omnivore). Our measurements of VO(2) and C(wet) under resting conditions agree with those previously reported for other marsupials. We expected that C. philander would show a lower maximal sustained VO(2), compared to the other two species, based on its more reduced skeletal muscle mass. However, the values obtained for C. philander were not statistically different (ANOVA) from those obtained for the other two species. When exposed to low ambient temperature (12 degrees C), differences among the three species were detected, i.e., M. nudicaudatus did not survive, while the other two species were able to reduce their T(b) under such conditions. C. philander gradually decreases its T(b) when cold exposed, and P. opossum shows a more pronounced T(b) drop only when exposure to low ambient temperatures occurs for a more prolonged period of time.     

Seasonal changes in male and female bill knob size in the mute swan Cygnus olor

Sexual selection theory predicts that sexually selected ornaments are costly to maintain and, as condition-dependent signals, are likely to vary in attractiveness with season and age. Mute swans Cygnus olor possess a black, fleshy knob at the base of the bill, which is present in both sexes. Using measures calculated from digital photographs taken over two years we monitored changes in the size of the bill knob in individual swans throughout the breeding season. Our longitudinal data show that bill knob size is highly dynamic. Relative bill knob size was larger in males than females and was consistently greater for breeding males than for non-breeders. For males, relative bill knob size peaked during cygnet hatching, when male protection of the brood is most important, and was smallest during moult. In females, breeders had larger bill knobs than non-breeders at all times apart from immediately after egg-laying and incubation, when the reverse was true, presumably reflecting the costs of reproduction. Body mass was a highly significant predictor of relative bill knob size in both sexes, as was age, with an initial increase and then later a decline in relative ornament size across the lifetime of male birds. The bill knob ornament in mute swans thus appears to be a condition-dependent, highly malleable trait. It accurately reflects the differing pressures experienced by individual birds as they progress through the breeding season, suggesting selection by both intra- and inter-sexual forces.     

Jalcophila boliviensis,a new species of South American Asteraceae (Gnaphalieae)

The new species, Jalcophila boliviensis (Asteraceae: Gnaphalieae) is described and illustrated. A discussion of the systematic position of Jalcophila Dillon & Sagást. and a key to the three species of the genus are presented.