The constraints imposed by morphology on acoustic signals have received little attention in non-vocal sound communications. Storks (family Ciconiidae) are 'voiceless' birds, as they have lost syringeal muscles and gained bill sounds for acoustic communication. In the bill-clattering displays performed for courtship or agonistic interactions with conspecifics, many species rapidly strike the mandibles against each other in succession to produce percussive 'machine-gun-like rattles'. By looking into among-species variations in the temporal structures of bill-clattering sounds, we asked whether the evolution of rhythms is influenced by morphological traits. Specifically, based on the simple physics of the bill as a third-class lever, we predicted that longer bills would serve as a velocity multiplier. Our phylogenetic comparative analyses confirmed this idea, revealing that longer-billed species are characterized by faster bill-clattering. Interestingly, this relationship is opposed to commonly accepted and previously observed size-relationships in acoustic communication, where species with bigger bodies or bills tend to produce slower sound signals. The findings here point the way towards future research on whether sonation (mechanical sounds) can convey the attributes of signallers, particularly given the long bills of species such as storks. We propose that simple biomechanics could highlight new avenues in studying the evolution of percussive sounds.

Long-lived territorial bird populations often consist of a few territorial breeding adults and many nonbreeding individuals. Some populations are threatened by anthropogenic activities, because of human conflicts for high-quality breeding habitat. Therefore, habitat restoration projects have been widely implemented to improve avian population status. In conjunction with habitat restoration, conservation translocations have been increasingly implemented. Adequate nonbreeder survival can be a key factor in the success of these attempts because nonbreeding birds may represent reservoirs for the replacement of breeders. The maintenance of breeding pair numbers is also influenced by the transition rate of nonbreeders to breeders. The reintroduction of Oriental Stork (Ciconia boyciana), a long-lived, territorial, endangered species, was initiated in Japan in 2005 using captive birds in hopes of increasing the population's use of restored habitat. Our objective of this study was to elucidate the factors determining reintroduced stork survival and recruitment to the breeding populations. We estimated the survival rate and breeding participation rate by sex, age, generation, wild-born or not, haplotypes, and breeding status in storks reintroduced during 2005-2022 using Bayesian hierarchical models. There was no significant difference in survival rate between nonbreeders and breeders. However, the survival rate was lower in wild-born birds than released birds, which may be related to the longer-distance natal dispersal of new generations. Accelerated habitat restoration around breeding areas and preventive measures for collision with human-built structures should be implemented for the sustained growth of reintroduced populations. A low survival rate was also detected for a specific mitochondrial DNA (mtDNA) haplotype that accounts for the majority of the reintroduced population. This phenomenon might be explained by mtDNA-encoded mutations. Moreover, captive breeding and release history might contribute to an increase in the proportion of this haplotype in the wild. center dot Adequate nonbreeder survival and transition rate of nonbreeders to breeders are key factors for the success of conservation translocations in long-lived territorial birds.center dot The purpose of this study was to elucidate the factors determining survival and recruitment to breeding populations in the reintroduced Oriental Stork.center dot Survival rate did not differ between nonbreeders and breeders.center dot The survival rate was lower in wild-born birds than released birds, which may be related to the longer-distance natal dispersal of new generations.center dot A low survival rate was detected for a specific mtDNA haplotype of the reintroduced population, which might be explained by mtDNA-encoded mutations. Las poblaciones de aves territoriales de larga vida a menudo estan compuestas por unos pocos adultos territoriales reproductores y muchos individuos no reproductores. Algunas poblaciones estan amenazadas por actividades antropogenicas, debido a conflictos humanos por los habitats reproductivos de alta calidad. Por lo tanto, se han implementado ampliamente proyectos de restauracion de habitats para mejorar el estado de las poblaciones de aves. Junto con la restauracion del habitat, las translocaciones de conservacion se han implementado cada vez mas. La supervivencia adecuada de los individuos no reproductores puede ser un factor clave en el exito de estos intentos, ya que las aves no reproductoras pueden representar reservorios para reemplazar a las reproductoras. El mantenimiento del numero de parejas reproductoras tambien esta influenciado por la tasa de transicion de no reproductores a reproductores. La reintroduccion de Ciconia boyciana, una especie territorial de larga vida en peligro de extincion, se inicio en Japon en 2005 utilizando aves cautivas con la esperanza de aumentar el uso del habitat restaurado por parte de la poblacion. Nuestro objetivo en este estudio fue dilucidar los factores que determinan la supervivencia y el reclutamiento de los individuos reintroducidos en las poblaciones reproductivas. Estimamos la tasa de supervivencia y la tasa de participacion reproductiva considerando sexo, edad, generacion, nacidos en libertad o no, haplotipos y estado reproductivo en individuos reintroducidos de C. boyciana durante 2005-2022 utilizando modelos jerarquicos bayesianos. No hubo una diferencia significativa en la tasa de supervivencia entre no reproductores y reproductores. Sin embargo, la tasa de supervivencia fue menor en aves nacidas en libertad que en aves liberadas, lo que puede estar relacionado con la dispersion natal a larga distancia de las nuevas generaciones. Deberian implementarse la restauracion acelerada del habitat alrededor de las areas reproductivas y medidas preventivas que eviten las colisiones con estructuras antropicas para lograr el crecimiento sostenido de las poblaciones reintroducidas. Tambien se detecto una baja tasa de supervivencia para un haplotipo especifico del ADN mitocondrial (ADNmt) que representa a la mayoria de la poblacion reintroducida. Este fenomeno podria explicarse por mutaciones codificadas en el ADNmt. Ademas, la historia de cria en cautiverio y liberacion podria contribuir a un aumento en la proporcion de este haplotipo en la naturaleza.

Many reintroduction attempts have encountered difficulties with long-distance dispersal of the released animals. In previous studies, release techniques and ages of the released individuals have been tested separately to examine their influence on post-release dispersal, with varied results. Dispersal patterns may be determined by a combination of release techniques and individual characteristics (age or rearing history). To reintroduce the Oriental Stork ( Ciconia boyciana ) to Japan, we released 1–7-year-old birds using soft and hard release techniques. The effects of different combinations of release techniques and ages or rearing histories on Oriental Stork dispersal distance and area within the first year after release were documented using global positioning system tracking data. Following soft and hard releases, some 1-year-old released birds became widely dispersed. However, all 1–3-year-old birds stayed in close proximity to the release sites. Therefore, hard-release techniques may be less problematic for Oriental Stork reintroduction if 1–3-year-old birds are selected for release. Soft-released first-year birds that had larger core areas and longer dispersal distances were not transported and trained, had only family members as their cage mates, and were reared by foster parents until fledging. Therefore, rearing histories could be an important factor in determining dispersal area and distance. To prevent the long-distance dispersal of species with the same ecological characteristics as the Oriental Stork (carnivorous, territorial, unattracted to conspecifics), we suggest hard-releasing 1–3-year-old birds.

Marine protected areas (MPAs), particularly large MPAs, are increasing in number and size around the globe in part to facilitate the conservation of marine megafauna under the assumption that large-scale MPAs better align with vagile life histories; however, this alignment is not well established. Using a global tracking dataset from 36 species across five taxa, chosen to reflect the span of home range size in highly mobile marine megafauna, we show most MPAs are too small to encompass complete home ranges of most species. Based on size alone, 40% of existing MPAs could encompass the home ranges of the smallest ranged species, while only < 1% of existing MPAs could encompass those of the largest ranged species. Further, where home ranges and MPAs overlapped in real geographic space, MPAs encompassed < 5% of core areas used by all species. Despite most home ranges of mobile marine megafauna being much larger than existing MPAs, we demonstrate how benefits from MPAs are still likely to accrue by targeting seasonal aggregations and critical life history stages and through other management techniques.

Summary Species restoration through reintroduction and reinforcement is widely considered as an effective method for the conservation of threatened animals. Although these approaches have been increasingly implemented over the last half-century, many attempts have failed. Dispersal behaviour is one of the key factors determining reintroduction success. We reported the demographic composition and dispersal pattern (i.e., post-release and natal dispersal) of a reintroduced Oriental Stork Ciconia boyciana population in Japan and identified the determinants of breeding success in 2005–2019. We hypothesized that one of the key determinants of breeding success is the density-dependent effect through post-release and natal dispersal. The F1 generation occurrence corresponded to two years, F2 to seven, F3 to 11, and F4 to 14 years after initial reintroduction. Wild-born birds accounted for 74% of the reintroduced population at F4 occurrence. Post-release dispersal distances were shorter than natal dispersal. Inter-nest distance was selected as the key factor determining breeding success. These results may have been due to feeding habitat restoration and conspecific interactions. In conclusion, steady recruitment to the next generation is thought to be due to a moderate natal dispersal and the subsequent low breeding density of wild-born birds.

Understanding encounters between marine predators and fisheries across national borders and outside national jurisdictions offers new perspectives on unwanted interactions to inform ocean management and predator conservation. Although seabird-fisheries overlap has been documented at many scales, remote identification of vessel encounters has lagged because vessel movement data often are lacking. Here, we reveal albatrosses-fisheries associations throughout the North Pacific Ocean. We identified commercial fishing operations using Global Fishing Watch data and algorithms to detect fishing vessels. We compiled GPS tracks of adult black-footed Phoebastria nigripes and Laysan Phoebastria immutabilis albatrosses, and juvenile short-tailed albatrosses Phoebastria albatrus. We quantified albatrosses-vessel encounters based on the assumed distance that birds perceive a vessel (<= 30 km), and associations when birds approached vessels (<= 3 km). For each event we quantified bird behaviour, environmental conditions and vessel characteristics and then applied Boosted Regression Tree models to identify drivers and the duration of these associations. In regions of greater fishing effort short-tailed and Laysan albatrosses associated with fishing vessels more frequently. However, fishing method (e.g. longline, trawl) and flag nation did not influence association prevalence nor the duration short-tailed albatrosses attended fishing vessels. Laysan albatrosses were more likely to approach longer vessels. Black-footed albatrosses were the most likely to approach vessels (61.9%), but limited vessel encounters (n = 21) prevented evaluation of meaningful explanatory models for this species of high bycatch concern. Temporal variables (time of day and month) and bird behavioural state helped explain when short-tailed albatrosses were in close proximity to a vessel, but environmental conditions were more important for explaining interaction duration. Laysan albatrosses were more likely to associate with vessels while searching and during the last 60% (by time) of their trips. Our results provide specific species-fisheries insight regarding contributing factors of high-risk associations that could lead to bycatch of albatrosses within national waters and on the high seas. Policy implications. Given the availability of Global Fishing Watch data, our analysis can be applied to other marine predators-if tracking data are available-to identify spatio-temporal patterns, vessel specific attributes and predator behaviours associated with fishing vessel associations, thus enabling predictive modelling and targeted mitigation measures.

再導入により野外での個体数が増えつつある絶滅危惧種のコウノトリCiconia boycianaについて,保全の観点からなわばりと行動圏に着目し,給餌に依存しない繁殖ペアの行動データを20か月間集めた.なわばりについては,カーネル法による行動圏の推定を行い,ペア雌雄の「重複する行動圏」と「他個体との対戦位置」を関連付けて,最も妥当な範囲を検討した.その結果,雌雄で重複する行動圏の密度40%,面積65.82 haの範囲が調査対象ペアのなわばりであると結論付けられた.また,直接対戦(つつき合い,追い払い)はオスが主体的に行っていることが明らかになったが,非直接対戦(クラッタリングによる威嚇)は雌雄ともに同程度行っていた.行動圏の面積については,"2017–2018非繁殖期"から"2019造巣期と交尾期"までの間,ペア雌雄の変化は同調したが,"2019抱卵期"と"2019育雛前期"は乖離し,オスがなわばり周辺に留まっていたのに対して,メスはなわばり外も利用していた.このことは,雌雄で保全すべきエリアが異なる可能性を示唆している.

The risk of marine organisms ingesting plastics has become a growing concern due to hazard chemicals in plastics. To identify compounds to which seabirds potentially have substantial exposure, 194 plastics fragments and pellets ingested by seabirds, i.e., northern fulmars from the Faroe Islands, and laysan albatross and black footed albatross from Mukojima Island, were analyzed piece by piece. Four kinds of UV stabilizers, 2 brominated flame retardants, and styrene oligomers were detected at detection frequencies of 4.6%, 2.1%, and 2.1%, respectively. Concentrations ranging from not detected (n.d.) - 1700 mu g/g were measured for UV stabilizers, n.d. 1100 mu g/g for flame retardants, and n.d. - 3200 mu g/g for styrene oligomers. We found that these chemicals could be retained in plastics during drifting and fragmentation in the ocean and transported to seabirds. This type of transport via plastics can be direct pathway that introduces hazardous compounds to marine organisms.

Abstract Pelagic top predators that range widely over thousands of kilometres increase their turn rate and slow their movements within an area of mesoscale (<102 km). This behavior is known as “Area Restricted Search, or ARS” and is associated with aggregations of prey. Foraging range, diving behavior, and ARS were studied for nine Black-footed Albatrosses Phoebastria nigripes rearing chicks on Mukojima in the Ogasawara Islands, using GPS and time-depth data-loggers. Their prey composition was examined using regurgitations. They fed on fish, fish eggs and squid within a range of 96–427 km from the colony. They made shallow (0.6±0.2 m) dives in day-time (2.2 dives per hour of at sea time) but rarely did so at night (0.1 dives per hour of at sea time). ARS behavior was observed at the scale of 11–71 km during day- and night-time and tended to occur in locations with relatively high primary production.

We compared the number of individuals and juvenile-to-adult ratio of Rustic Bunting Emberiza rustica, Black-faced Bunting E. spodocephala, and Reed Bunting E. schoeniclus captured in sound-lured and unlured mist nets at an autumn stopover site during October and November 2004-2011. The numbers of all three buntings captured and the proportion of juveniles of Black-faced and Reed buntings increased with sound luring. Use of sound luring could help further our understanding of migration ecology and conservation of the globally vulnerable Rustic Bunting and its congeners through increasing the number of individuals captured and banded.

Situated at high positions on marine food webs, seabirds accumulate high concentrations of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs). Our previous studies proposed the usefulness of seabirds preen gland oil as a nondestructive biomonitoring tool. The present study applied this approach to 154 adult birds of 24 species collected from 11 locations during 2005–2016 to demonstrate the utility of preen gland oil as a tool for global monitoring POPs, i.e., PCBs, DDTs, and HCHs. Concentrations of the POPs were higher in the Northern Hemisphere than in the Southern Hemisphere. In particular, ∑20PCBs and∑DDTs were highly concentrated in European shags (Phalacrocorax aristotelis) and Japanese cormorants (Phalacrocorax capillatus), explainable by a diet of benthic fishes. Higher concentrations of γ-HCH were detected in species from the polar regions, possibly reflecting the recent exposure and global distillation of ∑HCHs. We examined the relationship between age and POP concentrations in preen gland oil from 20 male European shags, aged 3–16 years old. Concentrations and compositions of POPs were not related to age. We also examined sex differences in the POP concentrations from 24 streaked shearwaters (Calonectris leucomelas) and did not detect a sex bias. These results underline the importance of the geographic concentration patterns and the dietary behavior as determinants species-specific POPs concentrations in preen gland oil.

The ability of juveniles of wide-ranging species to locate distant foraging regions can rely on innate or learned information. Reliance on innate cues could be problematic when conservation actions facilitate reintroduction. In the North Pacific, the short-tailed albatross Phoebastria albatrus is recovering from extensive harvesting, and has recently benefited from translocation efforts. Yet little is known about how naïve juveniles disperse or about individual distributions of immature short-tailed albatrosses. The primary goals of this study were to quantify the ontogeny of movement patterns and spatial distributions and compare these between naturally reared and translocated short-tailed albatrosses. We tracked 51 albatrosses for up to 5 years post-fledging: naturally reared chicks from their natal colony on Torishima, Japan, and chicks that were translocated 350 km to the southeast to Mukojima, Japan. Initial, more northerly dispersal of translocated fledglings suggests the ability to adjust to a new departure location. Fledglings’ departure paths differed from previously tracked adults departing Torishima, yet like adults, the majority of fledglings (81%) reached the Bering Sea that first summer, further supporting large-scale innate orientation abilities. Juveniles showed strong seasonal changes in distributions, traveling more in winter and occupying regions not typically used by adults (e.g. California Current, Sea of Okhotsk). As they aged, juveniles began to exhibit habitat fidelity to shelf-break regions, as anticipated from prior studies, yet continued to explore new regions with low levels of spatial fidelity. Juvenile short-tailed albatrosses explored almost the entire species range, highlighting the impressive capacity of individuals to transverse the North Pacific.

Restoration or establishment of colonies using translocation and hand-rearing can be an effective tool for conserving birds. However, well-designed post-release evaluation studies for long-lived species are rarely implemented. We investigated the attendance and breeding attempts of hand-reared short-tailed albatross (STAL) Phoebastria albatrus chicks (n = 69) translocated to a historic breeding island in the Ogasawara Islands, 350 km from the source colony, for 8 consecutive years after the first translocation. Thirty-nine percent of hand-reared birds (n = 27) returned to the translocation site at least once per breeding season, of which 67% (n = 18) also visited the natal island. The number of hand-reared birds returning each year was lower at the translocation site (mean: 0.3-2.3 birds per day) versus the natal island (0.4-3.5 birds per day). The first breeding attempt occurred 5 years after the first translocation. Three pairs (producing three chicks) recruited to the translocation site or neighboring islands and five pairs (producing nine chicks) recruited to the natal island by 8 years after the first translocation. Every hand-reared bird that raised a chick paired with a naturally reared bird. At the translocation site and neighboring islands, two hand-reared birds paired with a mate from the natal island and a breeding colony 1850 km away, respectively, while the parents of the third chick were unknown. Their breeding at the translocation region was observed among conspecific social attractants (decoys, audio playback; one pair) or congeners (two pairs). Our preliminary results suggest that even though more translocated and hand-reared albatrosses visited and recruited to their natal island compared to the translocation site, the early re-establishment of breeding by short-tailed albatrosses in the Ogasawara Islands 80 years after extirpation would not have occurred without the initial translocation effort. Further study is needed, however, to fully understand formation of breeding colonies beyond conspecific attraction and philopatry.

Older or heavier Rhinoceros Auklet Cerorhinca monocerata chicks are less likely to remain in their nest during pre-fledging mass recession. Older or heavier chicks have longer wings but the individual variation in wing length at fledging is small. To identify proximate triggers of fledging from a mix of candidates when chicks experienced mass recession, we selected 30 nest boxes each containing a chick and provided half of them with 30-60 g of supplementary foods in an attempt to expand their variation in growth rate. When chicks reached the minimum wing length required for fledging (130 mm), we stopped all provisioning (supplementary and parental) by closing a hatch on the nest box entrance thereby simulating mass recession and inducing fledging. With these treatments, we examined whether timing of fledging (=duration of mass recession) was only triggered by wing length to a threshold size or whether timing of fledging was delayed by younger age at peak mass or lighter peak body mass. Our results indicate that younger chicks remained in their nests longer than older chicks at the beginning of pre-fledging mass recession, regardless of the small variation in wing length among individuals. Annual variation in the duration of mass recession was also detected but body mass was not the trigger for fledging. Measurement of baseline corticosterone level indicated a negative trend between the corticosterone level and the number of days between the measurement date and the fledging date.

Parent Procellariiformes alternate between long-range foraging trips to feed in distant productive marine areas and short-range trips to feed in less productive areas around their breeding colony. Foraging trip duration, diet, energy expenditure, and chick growth of Streaked Shearwaters Calonectris leucomelas were compared between two colonies, one on Mikura Island located in the warm and less productive waters of the Kuroshio current, and the other on Sangan Island located in the cold and more productive waters of the Kuroshio/Oyashio transition zone. Parent shearwaters breeding on Mikura alternated between short (<= 3 days) trips to Kuroshio waters in order to provision their chicks and long (>3 days) trips to the cold Oyashio region in order to accumulate energy reserves for themselves. Shearwaters breeding on Sangan mainly took short trips (<= 2 days) to the nearby Kuroshio/Oyashio transition zone, but also took longer trips (>2 days) to the cold Oyashio region. Parent shearwaters breeding on Mikura, however, made more frequent long trips (24%) than those breeding on Sangan (9%). Parents at both colonies commonly brought Japanese Anchovy Engraulis japonica and Darkedged-wing Flyingfish Cypselurus hiraii for their young, while parents on Mikura also brought Pacific Saury Cololabis saira and stomach oil after long trips. Parents on Mikura delivered energy at a lower rate, resulting in lower chick growth rates and smaller fledging masses than on Sangan. Unlike other Procellariiformes seabirds, shearwater parents on Sangan accumulate their own body reserves even during the chick rearing period because of better foraging efficiency than on Mikura. This may indicate that chicks were satiated by the meals delivered to them allowing parents to utilize the remaining provisions for their own body reserves.

現在の小笠原諸島では自然再生事業による様々な生態系の変化が生じている．その効果を判定するためには，生物相の変化をきめ細かにモニタリングすることが必要である．小笠原諸島の無人島である聟島では，自然再生事業によって侵略的な外来哺乳類であるヤギCapra aegagrusとクマネズミRattus rattusが近年駆除されたが，その駆除に対する陸鳥への効果を判定出来る基礎的なデータがない．本研究は現在の聟島における鳥類の生息状況を定量的に調べることで，自然再生事業による今後のモニタリングに貢献することを目的とする．今回，我々はルートセンサスを島内2カ所で行い，ネズミ駆除前（2007年）と駆除直後（2011–2012年）における陸鳥の種数と個体数の比較を行った．さらに，2008年から2012年の2月から5月の聟島滞在中に観察された鳥類の種類と数も記録した．ルートセンサスの結果，継続的に観察された在来種のイソヒヨドリMonticola solitariusと移入種のメジロZosterops japonicusのうち，1つのルートにおいてイソヒヨドリ個体数の増加が駆除後に確認された以外は，変化が見られなかった．目視観察では，合計74種のうち32種が聟島で新たに観察された．これらの結果は，将来的に聟島における自然再生事業の効果の評価に寄与すると期待できる．

生態系サービスの持続的利用を考える上で，生物がどのようなサービスを人間に提供するかだけでなく，このサービスを提供する生物が環境変化によってどのような影響を受けているかの双方の理解が不可欠である．本研究では，東南アジアから繁殖のために日本に渡ってくる夏鳥の中から，気象庁生物季節観測（1953～2008年）および標識調査（1961～1971年，1982～2011年）で情報が多く得られているツバメ，カッコウ，オオヨシキリ，コムクドリを選び，成鳥および巣内雛の出現時期の長期変化，両時期と前冬および当春の気温との関係，および植物，昆虫の春期初認日との関係について調べた．その結果，ツバメ，オオヨシキリ，コムクドリの成鳥および巣内雛は，出現時期が早期化する傾向が見られたが，カッコウだけは出現時期が近年晩期化する傾向が見られた．ツバメ，オオヨシキリの成鳥および巣内雛の出現時期は，気温が高い年ほど早期化する傾向が見られたが，カッコウの出現時期は気温が高い年ほど晩期化する傾向が見られた．これらの長期変化の速度は，一部を除いて，欧米の先行研究の結果からの大きな逸脱は見られなかった．また，これら鳥類と植物および昆虫の出現時期とのずれは一定で推移しているとは言えなかったが，早期化あるいは晩期化する鳥類を隔てる要因や，フェノロジカルミスマッチをもたらす要因について明らかにすることはできなかった．今後フェノロジカルミスマッチに注目した研究を進める際には地域差を考慮した解析が必要である．