Columbiforms (pigeons and doves) are distributed worldwide, including on remote oceanic islands. Thus, they have been regarded as model species of island evolution and species interactions. Reducing dispersal ability is a well-known evolutionary direction among island organisms, which is more complex for island Columbiforms. Here, I reviewed their evolution of maintaining the dispersal ability, movement patterns among islands, and the ecological function of their movement. Although a general trend of reduction in flight muscle is shown, some studies claim that the island Columbiforms maintain or even develop their dispersive phenotypes after colonizing islands, enabling them to move among islands. This is likely related to niche expansion and adaptation to island habitats with unstable resource availability. Interisland movement was reported in at least nine genera with two movement patterns: 1) daily movement between neighboring islands and 2) seasonal or nomadic movement among remote islands. The former is related to their daily foraging trips between nesting or roosting islands and foraging islands, and the latter may be due to unpredictable resource availability within an archipelago. Such movement contributes to long-distance seed dispersal among islands, including neighboring islands and even across an entire archipelago, which may affect plant distribution and gene flow in island ecosystems. This review provides a perspective on island ornithology and provides a foundation for further studies.

Climate change affects the timing and the length of the migration routes of migratory birds. This can lead to evolutionary changes in body mass, length of wing and tarsus. In the present study, we examined changes in wing length over a time scale of nearly two centuries for six long-distance migratory songbird species nesting in northern Eurasia. Given that long-term bird ringing data are not available for these species, we compared data measured in recent years at the Baikal Bird Ringing Station with measurements of museum specimens collected between 1826 and 2010. A total of 446 museum specimens and 140 ringed birds were used for the study. Our results showed no significant change in wing length with the exception of Red-flanked Bluetail Tarsiger cyanurus (a decrease) and Olive-backed Pipits Anthus hodgsoni (an increase). This suggests that the results are similar to the results of other studies, where stable, increasing, and decreasing trends have been shown. Climate change may affect migration patterns, with more species becoming resident and with certain migration routes becoming shorter. In the latter case, migratory birds may also experience a reduction in wing length, and our results suggest that this may be the case in most Siberian Passerines. However, it should be taken into account that distribution ranges may also change, as breeding success increases and the climate becomes more favourable. Furthermore, birds nest further north, so the length of the migration route may not change. Therefore, their wing length does not necessarily change.

Climate-driven changes in the abundance, distribution, and migration patterns of forage fish affect the diet composition of seabirds. Decadal climate changes, known as regime shifts, have occurred several times in the Sea of Japan, influencing the food web and leading to shifts in the diet of diving seabird species. To examine whether a long-range surface-feeding species, Streaked Shearwater Calonectris leucomelas, switched diet in response to the 2013/2014 regime shift, we sampled 826 stomach contents from individuals at Awashima Island between 2008 and 2020. They fed mainly on Japanese Anchovy Engraulis japonicus and Bullet Mackerel Auxis rochei, with benthic fish as minor prey, both during the negative and positive phases of the Pacific Decadal Oscillation (PDO) before and after the 2013/2014 regime shift, thus showing no evidence of prey switching. Although fisheries landings of Japanese Anchovy and Bullet Mackerel showed decreasing trends after the 2013/2014 regime shift, with a rise in cold-water Japanese Sardine (Sardinops melanostictus) dominance, this change was not reflected in the shearwater diet. Streaked Shearwater, a highly mobile and adaptable seabird species with an extensive foraging range, maintained a relatively stable diet, even under unpredictable environmental conditions including climate shifts.

In Japan, Crested Ibis Nipponia nippon is a special natural treasure and a specified national endangered species of Wild Fauna and Flora. This species became extinct in the wild in Japan in 1981. The current captive population, which was established in Japan in 1999, stems from a total of seven founders provided by China to facilitate captive breeding for release back into the wild. Since the reintroduction program was initiated in 2008, the captive population has played a critical role as the source of the released birds and hence the gene pool of the reintroduced population. In this study, several population genetic parameters and the genetic diversity of the captive population were estimated using pedigree data of individuals including all of the founders. The effective population size was estimated to be 11.2 in 2004 and 25.8 in 2021 with a gradual increase in recent years. The average degree of inbreeding was 2.2% in 2004 and 8.9% in 2018, after which it began to decline. The effective number of founders was 2.67 in 2004, rising to 4.96 in 2021, while that of non-founders was 22.8 in 2021. The value of founder genome equivalents was 4.08 in 2021, showing a consistent increase from 2.38 in 2004. The total loss of genetic diversity in 2021 was 0.123, and had decreased steadily from 0.210 in 2004. This was found to be attributed to the losses of 0.071 (58%), 0.029 (24%) and 0.020 (18%) due to the limited number of founders, the unequal genetic contributions of founders, and the population bottleneck and Mendelian sampling, respectively. In conclusion, while this study has revealed generally desirable trends of genetic diversity and population genetic parameters over about 20 years, it is suggested that further efforts should be made to increase genetic diversity beyond the current level.

Mercury (Hg) contamination impacts the corticosterone stress response via the hypothalamic-pituitary-adrenal axis in some bird species. Any alteration of the normal function of the stress response can have adverse effects on physiological functions, health and survival. However, the effects of Hg on the stress response vary between bird species. In this study we investigated the relationship between Hg concentrations and corticosterone levels in the blood of Black-tailed Gull Larus crassirostris to understand the effect of Hg contamination on the species' corticosterone stress response. We found no effect of Hg on corticosterone levels in adult Black-tailed Gull. One possible reason for this may be related to the lack of correlation between Hg accumulation in the blood and Hg accumulation in the adrenal glands, the main organ that regulates corticosterone levels.

We monitored 10 breeding attempts made by Lesser Kestrel Falco naumanni using camera traps. We began our field surveys on 20th June each year as this period coincided with the beginning of nestling period of Lesser Kestrel. We found that parental visiting frequency increased significantly as nestlings matured. However, a significant negative relationship was also found between overall parental nest-stay duration and nestling age. Furthermore, breeding males played a leading role in visiting their nests with or without food, whereas females played a major role in brooding the nestlings in the nests. We also found that parental feeding rate significantly increased as nestlings matured.