Minamitorishima, also known as Marcus Island, in the Ogasawara Islands, is the sole Japanese island located on the Pacific plate and the easternmost island in the country. Because of its unique biogeography, Minamitorishima plays a crucial role in preserving Japan's biodiversity. Although 11 seabird species bred here around 1900, overhunting and habitat destruction by guano mining led to the extinction of several species. Consequently, only three seabird species were comfirmed to breed on Minamitorishima in 2007: the Red-tailed Tropicbird Phaethon rubricauda, Brown Noddy Anous stolidus, and Sooty Tern Onychoprion fuscatus. As overhunting is no longer an issue and habitat conditions have been recovering, the seabird fauna was expected to be recovering. As there has been no recent monitoring of the recovery process, we conducted a field survey in May 2022, revealing the presence of a Black Noddy A. minutus colony with 139 arboreal nests and a White Tern Gygis alba chick in Casuarina equisetifolia tree, marking the first recorded breeding on Minamitorishima in approximately 120 years. Notably, the Black Noddy colony represents the largest one in Japan, and the record of White Tern breeding is the only one for the country. Additionally, Brown Noddy arboreal nests, which have not been recorded elsewhere in Japan, were discovered in C. equisetifolia trees, as well as a roost of Red-footed Booby Sula sula, another arboreal nesting species, comprising around 130 individuals, with one young bird observed carrying nesting material. No new breeding records were confirmed for ground nesting seabird species. C. equisetifolia was introduced deliberately on the island in 1963, and it has expanded its range over time. Overall, these findings highlight the remarkable changes in the seabird fauna of Minamitorishima in recent years due to the development of invasive forest. As C. equisetifolia is an invasive alien, the balance between its control and the conservation of seabirds needs to be carefully considered.

We investigated the impact of predation by Slaty-backed Gull Larus schistisagus on the chicks of Black-tailed Gull L. crassirostris and Slaty-backed Gull on Teuri Island, Hokkaido, Japan, in 2019. We collected 346 pellets and food remains from 10 Slaty-backed Gull nests (10–140 samples per nest). The average occurrence of seabird remains in the food samples was 47.5%; however, the occurrence of seabirds was much higher (66–90%) at three nests (designated as "seabird-predator nests"). Direct observation of the study area where 122 Black-tailed Gull and 17 Slaty-backed Gull were nesting, showed that the males of these three "seabird-predator nests" accounted for 75% of all predation attempts. Of these three, two males took 21% of Black-tailed Gull chicks and fledglings, and 24% of Slaty-backed Gull chicks in the study area. Black-tailed Gull chicks tended to be more vulnerable to predation if the chick hatched later and in the nests closer to these two seabird-predator nests, whereas these effects were not observed among fledglings. This study highlights the significance of specialist individual Slaty-backed Gull in determining the breeding success of Black-tailed Gull.

The endemic subspecies of Black Wood Pigeons Columba janthina nitens of the Ogasawara Islands (known in Japanese as Akagashira-karasubato or Red-headed Wood Pigeon), is morphologically and genetically distinct from the nominate subspecies C. j. janthina (known in Japanese simply as Karasubato). However, vocal characteristics, important traits in mate selection, have not previously been well studied in this species. Therefore, the vocalizations of both captive and wild C. j. nitens and C. j. janthina from two different regions were recorded and analyzed using sound spectrograms. Our results showed that C. j. nitens differs from C. j. janthina in the type of vocalizations, the notes and frequencies of the fundamental tones, and the accentuated harmonics of the "coo" song.

Gravid segments of an unknown tapeworm were obtained from the feces of four Ryukyu Scops Owls Otus elegans on Hateruma Island, Japan, from June to September 2022. Morphological observations and molecular genetic characterization, based on the nuclear 28S ribosomal DNA region, were performed in order to identify the worm species. Morphological observations indicated that they were likely to be Cyclophyllidea of the Cestoda because of their genital pores. Furthermore, the 28S rDNA sequences generated from four samples were identical and showed high homology with the genus Monocercus of the family Dilepididae. These results indicate that the tapeworm taxa belonged to the Dilepididae, and most likely of the genus Monocercus. This is the first report of any cestode from Ryukyu Scops Owl, although identification to species was not possible.

The Sakhalin Grasshopper Warbler Locustella aminicola is a well-known summer visitor which breeds in Hokkaidō. However, in late July 2023, several males were observed and recorded singing at Shiriya-zaki (Cape Shiriya) on the Shimokita Peninsula, in northern Aomori Prefecture (northernmost Honshu). Sound spectrograms of songs were analyzed and classified to song types by patterns of fluctuations in the frequency of each note and in intervals between each note in one song. Mapping of multiple individuals singing simultaneously and individual identification by song repertoires suggest that at least six males sang at nine different points. This is the first report of possible breeding area in Honshu.