Migration routes and differences in migration strategies of Whooper Swans between spring and autumn

Long-distance migratory birds travel more rapidly in spring than in autumn,as they face temporal breeding constraints.However,several species travel slower in spring owing to environmental influences,such as food availability and wind conditions.GPS trackers were attached to 17 Whooper Swans(Cygnus cygnus) inhabiting northeastern Mongolia,to determine their migration routes and stopover sites in spring and autumn.Differences between spring and autumn migrations,migration-influencing parameters,and the effect of spring stopover site temperatures were analyzed.Six swans completed perfect tours between their wintering and breeding sites,and these data were used for analysis.Spring migration lasted 57 days,with 49.2 days spent at 3.7 stopover sites.Autumn migration lasted 21.5 days,with 17.5 days spent at 1.0 stopover sites.Thus,the swans traveled more rapidly in autumn than in spring.Migration distance,number of stopovers,migration speed,and straightness were important migration determinants in both spring and autumn.Migration distance,stopover duration,number of stopovers,daily travel speed,travel duration,and migration speed differed significantly between spring and autumn.During spring migration,the temperature at the current stopover sites and that at the future stopover sites displayed significant variations(t=1585.8,df=631.6,p <0.001).These findings are critical for the conservation and management of Whooper Swans and their key habitats in East Asian regions,and the data are anticipated to make a particularly significant contribution toward developing detailed management plans for the conservation of their key habitats.

Aggressive behavioural interactions between swans(Cygnus spp.)and other waterbirds during winter:a webcam-based study

Background:Our understanding of any impacts of swans on other waterbirds(including other swans),and potential effects on waterbird community structure,remain limited by a paucity of fundamental behavioural and ecological data,including which species swans interact aggressively with and how frequently such interactions occur.Methods:Behavioural observations of aggression by swans and other waterbirds in winters 2018/2019 and 2019/2020,were carried out via live-streaming webcams at two wintering sites in the UK.All occurrence sampling was used to identify all aggressive interactions between conspecific or heterospecifics individuals,whilst focal observations were used to record the total time spent by swans on aggressive interactions with other swans.Binomial tests were then used to assess whether the proportion of intraspecific aggressive interactions of each species differed from 0.5(which would indicate equal numbers of intraspecific and interspecific interactions).Zero-inflated generalized linear mixed effects models(ZIGLMMs)were used to assess between-individual variation in the total time spent by swans on aggressive interactions with other swans.Results:All three swan species were most frequently aggressive towards,and received most aggression from,their conspecifics.Our 10-min focal observations showed that Whooper(Cygnus cygnus)and Bewick’s Swans(C.columbianus bewickii)spent 13.8±4.7 s(means±95%CI)and 1.4±0.3 s,respectively,on aggression with other swans.These durations were equivalent to 2.3%and 0.2%of the Whooper and Bewick’s Swan time-activity budgets,respectively.Model selection indicated that the time spent in aggressive interactions with other swans was best-explained by the number of other swans present for Whooper Swans,and an interactive effect of time of day and winter of observation for Bewick’s Swans.However,the relationship between swan numbers and Whooper Swan aggression times was not strong(R2=19.3%).Conclusions:Whilst swans do exhibit some aggression towards smaller waterbirds,the majority of aggression by swans is directed towards other swans.Aggression focused on conspecifics likely reflects greater overlap in resource use,and hence higher potential for competition,between individuals of the same species.Our study provides an example of how questions relating to avian behaviour can be addressed using methods of remote data collection such as live-streaming webcams.

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 diff erentiated 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 diff erences between those two parasites support C.cygnimorbus sp.nov.as a new species.