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Studies on the distribution of species are important to understanding the interspecific ecological niche and habitat selection through geographic environmental information. Particularly, vipers in the same genus have been an important topic because they show differences in the preferred geographical environment, depending on the distance of the phylogenetic relationship. This study investigated the geographical environment of red-tongued pit vipers (Gloydius ussuriensis) and Central Asian pit vipers (Gloydius intermedius) in the mountainous area, Cheonmasan Mountain County Park, South Korea, from April 2012 to October 2014, to understand the relationships among their habitat characteristics and ecological niche. Red-tongued pit vipers mainly lived in low altitude, wet valley areas with a low solar reflectance, while Central Asian pit vipers inhabited high altitude, dry land with large amounts of sunshine. As a result, our study supports that the ecological niche of red-tongued pit vipers and Central Asian pit vipers, inhibiting in Cheonmasan Mountain was overlapped low according to the majority of geographical environmental variables. The differentiated diet preference might be took into consideration as one of the potential key factors to the ecological niche differentiation among two species.

Azure-winged Magpies Cyanopica cyanus living in isolated plantations had higher nesting success away from habitat edges and lower breeding success away from conspecific nests.The study aims to find...

Bird nests are crucial for reproductive success since they serve as structures to hold the eggs and nestlings safely. Therefore, the structural characteristics of bird nests have optimally evolved to maximize reproductive success, which are known to be affected by various factors. We gathered information on the nest characteristics such as nest structure and constituent materials in the colonial breeding Azure-winged magpie (

Plastic ingestion studies in seabirds that analyse the frequency of occurrence and the characteristics of the plastics ingested by each species provide valuable information for marine environmental assessments by quantifying the impacts of marine debris on seabirds. We investigated the frequency of plastic ingestion from a sample of 387 individuals of 11 seabird species on the Korean Peninsula. We found evidence of plastic ingestion in red-breasted mergansers (Mergus serrator) (33.3%), Pacific loons (Gavia pacifica) (10.0%), Swinhoe's storm petrels (Hydrobates monorhis) (93.7%), black-tailed gulls (Larus crassirostris) (12.9%) and ancient murrelets (Synthliboramphus antiquus) (0.9%). In particular, it was observed that Swinhoe's storm petrels had the highest frequency of plastic ingestion, both in terms of the number of affected individuals, and the accumulated mass of plastic debris ingested. The majority of seabirds examined in our study had ingested microplastics, comprised predominantly of user plastics. This is the first report quantifying plastic ingestion in seabirds on the Korean Peninsula and in the broader area of the East Asian Seas.

The seabird plays an important role as one of the indicator species for the status of and changes within marine ecosystems. Therefore, the conservation of seabirds and their habitats is important for maintaining the structure and function of marine ecosystems. Biological invasions affect most ecosystems on oceanic islands. In particular, Rattus spp. is the invasive species with the greatest impact on the seabird population. Introduced predators, like rats, severely affect seabirds and endanger them worldwide. The breeding population of Streaked Shearwaters Calonectris leucomelas in Sasu Island is one of biggest seabird colonies in Korea, and the Norway Rat Rattus norvegicus is known as an alien predator in this island. In this study we investigated rates of burrow occupancy and breeding success of Streaked Shearwaters for 7 years, and the impact of Norway Rats on the breeding success of Streaked Shearwaters breeding in Sasu Island for 4 years. Our results show that the percentage of breeding burrows decreased according to breeding stage during several years in the monitoring period, and that predation by the Norway Rat was the main cause in hatching failures. Consequently, although our results indicate that their breeding population is not likely to decline, Norway Rats have been affecting the breeding status of Streaked Shearwaters on Sasu Island during the last decade.

In cooperatively breeding vertebrates, investment strategies of breeders and helpers may be affected by the sex of offspring that they provision because the fitness benefits gained from caring for sons or daughters will depend upon the fitness impacts of positive (i.e. local resource enhancement) and negative (i.e. local resource competition) social interactions between relatives. We investigated the relationship between provisioning effort by breeders and helpers and the sex of nestlings that they provision, using long-term data over 16 years and detailed behavioural observation of interactions between carers and offspring in a cooperatively breeding species, the long-tailed tit, Aegithalos caudatus . We predicted preferential care for male nestlings because males are the more helpful sex in the kin-selected social system of long-tailed tits. However, we found that despite the significant size difference between male and female nestlings, there was no evidence of facultative adjustment of provisioning effort by either breeders or helpers in relation to brood sex ratio. In addition, we found no evidence for sex-biased provisioning by carers, and no bias in the feeds received by nestlings according to their sex. Thus, we conclude that the provisioning strategy of long-tailed tits does not incorporate differential investment according to sex. We suggest that the unpredictable nature of helping in the atypical cooperative breeding system of long-tailed tits makes random provisioning effort in relation to nestling sex the best option for carers.

Cooperative breeding has evolved primarily in species in which individuals are organized into family groups, and kin selection is considered to be a major force in the evolution of helping behaviour. Family groups are generally thought to form through delayed or limited dispersal, but dispersal patterns vary considerably both between species and in different populations of the same species, and the relationship between dispersal, kinship and cooperation is poorly understood. In this study, we combined long-term observational and genetic data to compare the patterns of demography, kinship and helping in two populations of long-tailed tits, Aegithalos caudatus, a species that exhibits kin-biased helping by failed breeders but not delayed dispersal. Both populations had the same annual breeding success, but philopatric recruitment rates were significantly higher in one population, especially for females. This led to a correspondingly higher proportion of individuals having at least one close relative in that population. Surprisingly, however, there was no difference in the pattern of helping behaviour between the two populations in terms of helper prevalence, helper sex or the relatedness between helpers and the breeders they assisted. We discuss possible explanations and highlight the limitations of population-level analyses for understanding the relationship between demography and cooperation.

In cooperatively breeding species, the fitness consequences of producing sons or daughters depend upon the fitness impacts of positive (repayment hypothesis) and negative (local competition hypothesis) social interactions among relatives. In this study, we examine brood sex allocation in relation to the predictions of both the repayment and the local competition hypotheses in the cooperatively breeding long-tailed tit Aegithalos caudatus. At the population level, we found that annual brood sex ratio was negatively related to the number of male survivors across years, as predicted by the local competition hypothesis. At an individual level, in contrast to predictions of the repayment hypothesis, there was no evidence for facultative control of brood sex ratio. However, immigrant females produced a greater proportion of sons than resident females, a result consistent with both hypotheses. We conclude that female long-tailed tits make adaptive decisions about brood sex allocation.

Incubation routine and sex role of Streaked Shearwaters Calonectris leucomelas at Sasudo Island, in Jeju, South Korea, were studied during the incubation period, June to August in 2002. Incubation routine in Procellariiformes represents a sequence of alternating shifts taken in turn by female and male in a species-specific pattern. Hence, coordination of individual incubation rhythms between partners is crucial for successful breeding attempt. In Streaked Shearwaters, incubation routine represents a sequence of alternating shifts taken in turn by male and female. The first incubation shift was made by male after female had laid the egg. The mean incubation period was 50.8 days until hatching. Males had spent on average 26.5 days incubating and females 24.3 days accordingly. The mean duration of incubation shifts decreased progressively from 6th and 7th shift to hatching. Overall, males had spent more time incubating than females during the incubation period, but the mean duration of the incubation shift 5.6 days for males and 5.7 days for females did not differ between males and females. There were no effect of the body size of the breeding pair on incubation performance. For males the mean of body weight decreased during the incubation, whereas for females it remained approximately stable. In Streaked Shearwaters, the duration of incubation shift and subsequent foraging trip are related to loss of body weight during the period of fasting. In addition, coordination of individual incubation rhythms affects their incubation behaviour.

Background: Theoretical modelling of biparental care suggests that it can be a stable strategy if parents partially compensate for changes in behaviour by their partners. In empirical studies, however, parents occasionally match rather than compensate for the actions of their partners. The recently proposed ‘‘information model’’ adds to the earlier theory by factoring in information on brood value and/or need into parental decision-making. This leads to a variety of predicted parental responses following a change in partner work-rate depending on the information available to parents. Methodology/Principal Findings: We experimentally test predictions of the information model using a population of longtailed tits. We show that parental information on brood need varies systematically through the nestling period and use this variation to predict parental responses to an experimental increase in partner work-rate via playback of extra chick begging calls. When parental information is relatively high, partial compensation is predicted, whereas when parental information is low, a matching response is predicted. Conclusions/Significance: We find that although some responses are consistent with predictions, parents match a change in their partner’s work-rate more often than expected and we discuss possible explanations for our findings.

Helping behaviour in cooperative breeding systems has been attributed to kin selection, but the relative roles of direct and indirect fitness benefits in the evolution of such systems remain a matter of debate. In theory, helpers could maximize the indirect fitness benefits of cooperation by investing more in broods with whom they are more closely related, but there is little evidence for such fine-scale adjustment in helper effort among cooperative vertebrates. In this study, we used the unusual cooperative breeding system of the long-tailed tit Aegithalos caudatus to test the hypothesis that the provisioning effort of helpers was positively correlated with their kinship to broods. We first use pedigrees and microsatellite genotypes to characterize the relatedness between helpers and breeders from a 14 year field study. We used both pedigree and genetic approaches because long-tailed tits have access to pedigree information acquired through social relationships, but any fitness consequences will be determined by genetic relatedness. We then show using both pedigrees and genetic relatedness estimates that alloparental investment by helpers increases as their relatedness to the recipients of their care increases. We conclude that kin selection has played a critical role in moulding the investment decisions of helpers in this cooperatively breeding species.