Kiyoaki Ozaki

Wind, Waves, and Wing Loading: Morphological Specialization May Limit Range Expansion of Endangered Albatrosses

Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and potentially predicting future distributional limits of albatrosses globally, particularly with respect to climate change effects on basin-scale and regional wind fields.

Satellite tracking of the migration of the red‐crowned crane Grus japonensis

Autumn migration routes of red-crowned cranes, Grus japonensis, from two continental east Asian sites were documented in detail by satellite tracking. Two routes were identified: a 2200 km western route from Russia’s Khingansky Nature Reserve to coastal Jiangsu Province, China; and a 900 km eastern route from Lake Khanka (Russia) to the Korean Peninsula and the Demilitarized Zone. The most important rest-sites were identified as Panjin Marsh (China), coastal mudflats south-east of Tangshan City (China), the Yellow River mouth (China), Tumen River mouth (North Korea/China/Russia), Kumya (North Korea) and Cholwon (Korean DMZ). Movements within the wintering range were also recorded, including complex commuting between sites by individual cranes and patterns of daily movements within sites. These data should prove useful for conservation of the flyway.

Breeding-Season Sympatry Facilitates Genetic Exchange Among Allopatric Wintering Populations of Northern Pintails in Japan and California

Abstract. The global redistribution of pathogens, such as highly pathogenic avian influenza, has renewed interest in the connectivity of continental populations of birds. Populations of the Northern Pintail (Anas acuta) wintering in Japan and California are considered separate from a management perspective. We used data from band recoveries and population genetics to assess the degree of biological independence of these wintering populations. Distributions of recoveries in Russia of Northern Pintails originally banded during winter in North America overlapped with distributions of Northern Pintails banded during winter in Japan. Thus these allopatric wintering populations are partially sympatric during the breeding season. The primary areas of overlap were along the Chukotka and Kamchatka peninsulas in Russia. Furthermore, band recoveries demonstrated dispersal of individuals between wintering populations both from North America to Japan and vice versa. Genetic analyses of samples from both wintering populations showed little evidence of population differentiation. The combination of banding and genetic markers demonstrates that these two continental populations are linked by low levels of dispersal as well as likely interbreeding in eastern Russia. Although the levels of dispersal are inconsequential for population dynamics, the combination of dispersal and interbreeding represents a viable pathway for exchange of genes, diseases, and/or parasites.

Translocation and hand-rearing of the short-tailed albatross Phoebastria albatrus : early indicators of success for species conservation and island restoration

Many endemic species, particularly those on remote islands, have been driven to extinction or near extinction by anthropogenic influences. The short-tailed albatross Phoebastria albatrus once numbered in the millions but was thought to be extinct by the mid 20th century. Albatrosses, of the family Diomedeidae, are among the most threatened birds globally as a result of commercial exploitation, introduced predators, and mortality in commercial fisheries. We applied an experimental approach over 5 years to evaluate the translocation and hand-rearing of albatross chicks by comparing growth, physiological health indices, post-fledging survival, and migration patterns with a control group of naturally reared chicks in the source population. Hand-reared chicks had comparable or superior health and similar rates of immediate post-fledging mortality (15%), with mortality strongly female-biased in both groups. Hand-reared birds had longer post-fledging drift periods before attaining sustained flight (also female-biased) but comparable, albeit somewhat wider ranging, migration patterns to naturally reared chicks during their first 6 months at sea. Recruitment to the translocation site of a breeding pair that included a hand-reared bird occurred within 5 years of the first translocation. Success will ultimately depend on continued recruitment and breeding over the coming decades, given delayed breeding in these long-lived species. The results to date, however, have exceeded initial expectations and can inform potential reintroductions of other long-lived, migratory avian species with strong natal philopatry, and reintroductions of native species to former breeding islands.

Translocation and hand-rearing techniques for establishing a colony of threatened albatross

Summary Many breeding colonies of Procellariiformes have been threatened with extinction. Chick translocation has been shown to be an effective method for establishing new “safer” colonies of burrow-nesting species, but techniques for surface-nesting species have not been fully developed. The entire breeding population of the threatened Short-tailed Albatross Phoebastoria albatrus is restricted to two sites, Torishima Island and the Senkaku Islands, and neither site is secure due to volcanic activity or political instability. The Short-tailed Albatross Recovery Team has recommended facilitating the recovery of this species by establishing at least one additional colony through the translocation and hand-rearing of chicks at a safe historical breeding site. To evaluate the feasibility of this approach, we hand-reared 10 post-guard phase chicks of two related species in 2006–2007: Laysan Albatross P. immutabilis translocated from Midway Atoll to Kaua’i Island, Hawai’i and Black-footed Albatross P. nigripes translocated from a nearby islet in the Ogasawara (Bonin) Islands to Mukojima Island, Japan. In these pilot studies, 40% of Laysan Albatross chicks and 90% of Black-footed Albatross chicks fledged successfully. Following this groundwork, 40 post-guard phase Short-tailed Albatross chicks were translocated from Torishima Island to Mukojima Island in February 2008–2010 and hand-reared to fledging. Their fledging success has been 100% in all three years. Fledging body sizes were similar or greater in hand-reared chicks at the release site than parent-reared chicks on Torishima Island. There were significant differences in levels of some blood chemistry parameters between pre-fledging hand-reared and parent-reared chicks. The techniques developed in our studies have broad-reaching implications for the future conservation of threatened populations of other surface-nesting seabirds.

Three populations of non-breeding Roseate Terns (Sterna dougallii) in the Swain Reefs, Southern Great Barrier Reef, Australia

Abstract The Swain Reefs is an area of 2000 km2 of reefs and small coral cays at the southern end of the Great Barrier Reef in Queensland, Australia. Up to 5000 non-breeding Roseate Terns (Sterna dougallii) have been observed in the area during July, and 25 000 in January or February. We used a small cannon net to capture birds that we then banded and leg-flagged; we also collected biometric and moult data from appropriate samples. We captured 368 Roseate Terns in July of 1999, 2000 and 2001, and 3044 in January of 2002 and 2003. We determined that at least some Roseate Terns of the local Queensland breeding population (S. d. gracilis) from colonies on the Capricornia Cays occur in the Swain Reefs during July. Among the January captures were 44 birds carrying Japanese leg-bands and three carrying Taiwanese leg-bands. This is the first evidence that Asian-breeding Roseate Terns over-winter in the southern hemisphere. Subsequent sightings of flagged birds have occurred in the Japanese breeding colonies (with one recapture) and in breeding colonies in the southern Great Barrier Reef. Using plumage and moult characteristics we determined that 60% (15000 birds) of the Roseate Terns present in Swain Reefs in January belong to the Asian population (S. d. bangsi), 1.5% (375 birds) to the local population (S. d. gracilis), and the remaining 38% (9500 birds) were of unknown breeding origin.

The next common and widespread bunting to go? Global population decline in the Rustic Bunting Emberiza rustica

Populations of several long-distance migratory songbirds in Eurasia are in peril, drastically illustrated by the recent range-wide population collapse in the Yellow-breasted Bunting Emberiza aureola . There are signals of a strong decline also in the Rustic Bunting E. rustica , but no range-wide assessment of population trends in this superabundant and widespread bunting species has yet been undertaken. The conservation status of Rustic Bunting is ‘Least Concern’ on the global IUCN Red List, but it has recently been upgraded to ‘Vulnerable’ on the European Red List. To assess the Rustic Bunting’s global conservation status we compiled, for the first time, population data across its breeding and wintering ranges. The analysis reveals a 75–87% decline in overall population size over the last 30 years and a 32–91% decline over the last 10 years. The trend estimates indicate that the long-term (30-year) range-wide population decline in the Rustic Bunting is of similar magnitude to two well-known examples of declining species within the same genus, the Yellow-breasted Bunting and the Ortolan Bunting E. hortulana . The magnitude of the range-wide population decline over the last 10 years suggests that the Rustic Bunting could be upgraded from ‘Least Concern’ to ‘Vulnerable’ or ‘Endangered’ on the IUCN global Red List. Agricultural intensification in the wintering range and intensified levels of disturbance, including logging and fire, in the breeding range could be important drivers of the range-wide population decline, and persecution could also contribute. Untangling threat factors and their interactions on Rustic Bunting is necessary for conservation, but hampered by our currently limited understanding of the relationships between population dynamics and different threats.

Morphological Differences of Sex and Age in the Okinawa Rail Gallirallus okinawae

Abstract Morphological measurements of Okinawa Rail Gallirallus okinawae were made to evaluate methods of sex determination. Males were significantly larger (P<0.05) than females for 23 of the 25 features measured. Forward discriminant function analysis identified eight of the most useful measurements as maximum wing, exposed culmen, tarsus, total head, gape, bill height, body weight and third toe length. Further analysis selected total head (TH) and bill height (BH) as the most useful variables to determine sex and produced the discriminant function: 0.467×TH+0.827× BH-53.811, which correctly identified the sex of 100% of the individuals in the data set. Bill and iris color proved useful for determining age, as did the tip shape and color of the primary feathers. Characteristics of juvenile primaries were especially useful, since the birds retain their first year plumage until molting at about one year old. Individual variation also exists, however, requiring comprehensive evaluation of all biometrics and features for some individuals.

Invasive species and Pacific island bird conservation: a selective review of recent research featuring case studies of Swinhoe's storm petrel and the Okinawa and Guam rail.

Nowhere are the negative impacts of invasive species, such as ecosystem modification, predation, parasitism, and disease, more apparent than in the Pacific islands, where human contact triggered a massive avian extinction event that is still ongoing. Island bird species are inherently vulnerable to extinction due to their small, isolated populations and lack of evolved defenses against many predators. To prevent further extinctions, effective bird conservation strategies must be implemented to mitigate invasive species’ impacts, which often interact synergistically and collectively comprise some of the greatest threats to global biodiversity. At the 2014 International Ornithological Congress in Tokyo, Japan, researchers convened a symposium to address research and management of invasive species to benefit Pacific island bird conservation. Speakers presented research and conservation efforts from Japan, Korea, Guam, the Galápagos, and New Zealand, highlighting novel, poorly known threats to birds (e.g., mortality from invasive plant entanglement and invasive nest parasites) and providing updates on ongoing efforts to prevent island endemic species extinctions driven by invasive predators. In this paper we provide new details of research and conservation efforts on Swinhoe’s storm petrel (Oceanodroma monhris), the Okinawa rail (Gallirallus okinawae), and the Guam rail (G. owstoni), and put this research in context by briefly reviewing and synthesizing other relevant, recent studies on impacts of invasive species as they affect Pacific island bird conservation. We conclude by highlighting successful management strategies, recommending improvements for ongoing conservation efforts, and suggesting directions for future research.

Increasing the Number of Captured Migrant Buntings at an Autumn Stopover Site using Sound Lures

Abstract 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.