The degree to which individuals migrate among particular breeding, migration, and wintering sites can have important implications for prioritizing conservation efforts. Four subspecies of Dunlin (Calidris alpina) migrate along the East Asian−Australasian Flyway. Each subspecies has a distinct and well-defined breeding range, but their migration and winter ranges are poorly defined or unknown. We assessed the migratory connectivity of 3 of these subspecies by evaluating a dataset that encompasses 57 yr (1960–2017), and comprises more than 28,000 Dunlin banding records and 818 observations (71 recaptures and 747 band resightings). We present some of the first evidence that subspecific segregation likely occurs, with arcticola Dunlin wintering in areas of Japan, and other arcticola, actites, and sakhalina Dunlin wintering in areas of the Yellow and China seas. Observations indicate that whether an arcticola Dunlin winters in Japan or the Yellow and China seas is independent of their breeding location, sex, or age. Furthermore, observations indicate that ≥83% of arcticola Dunlin exhibit interannual site fidelity to specific wintering sites. This suggests that the degradation of specific wetland areas may negatively affect particular individuals of a particular subspecies (or combination of subspecies), and, if widespread, could result in population declines. Given the possible biases inherent in analyzing band recovery data, we recommend additional flyway-wide collaboration and the use of lightweight tracking devices and morphological and genetic assignment techniques to better quantify subspecies’ migratory movements and nonbreeding distributions. This information, when combined, will enable effective conservation efforts for this species across the East Asian−Australasian Flyway.

Summary The extent of intertidal flats in the Yellow Sea region has declined significantly in the past few decades, resulting in severe population declines in several waterbird species. The Yellow Sea region holds the primary stopover sites for many shorebirds during their migration to and from northern breeding grounds. However, the functional roles of these sites in shorebirds’ stopover ecology remain poorly understood. Through field surveys between July and November 2015, we investigated the stopover and moult schedules of migratory shorebirds along the southern Jiangsu coast, eastern China during their southbound migration, with a focus on the ‘Critically Endangered’ Spoon-billed Sandpiper Calidris pygmaea and ‘Endangered’ Nordmann’s Greenshank Tringa guttifer. Long-term count data indicate that both species regularly occur in globally important number in southern Jiangsu coast, constituting 16.67–49.34% and 64.0–80.67% of their global population estimates respectively, and it is highly likely that most adults undergo their primary moult during this southbound migration stopover. Our results show that Spoon-billed Sandpiper and Nordmann’s Greenshank staged for an extended period of time (66 and 84 days, respectively) to complete their primary moult. On average, Spoon-billed Sandpipers and Nordmann’s Greenshanks started moulting primary feathers on 8 August ± 4.52 and 27 July ± 1.56 days respectively, and their moult durations were 72.58 ± 9.08 and 65.09 ± 2.40 days. In addition, some individuals of several other shorebird species including the ‘Endangered’ Great Knot Calidris tenuirostris, ‘Near Threatened’ Bar-tailed Godwit Limosa lapponica, ‘Near Threatened’ Eurasian Curlew Numenius arquata and Greater Sand Plover Charadrius leschenaultii also underwent primary moult. Our work highlights the importance of the southern Jiangsu region as the primary moulting ground for these species, reinforcing that conservation of shorebird habitat including both intertidal flats and supratidal roosting sites in this region is critical to safeguard the future of some highly threatened shorebird species.

For some populations of Dunlins (Calidris alpina), determining the age of individuals on the nonbreeding grounds can be difficult. This difficulty arises in part because some populations undergo their primary molt during the boreal summer, leaving adult and first-year Dunlins with similar amounts of abrasion on their primaries. Ageing Dunlins is further complicated by the presence of adults with buff-fringed, inner median coverts in some populations, a feature often used to age juvenile Dunlins. We examined a number of characteristics helpful in the ageing Dunlins at nonbreeding areas along the East Asian-Australasian Flyway, including: (1) the pattern of white fringes on the inner primary coverts, (2) the color of fringes on the inner median wing coverts, (3) the color of the tip on the carpal covert, (4) the presence or absence of a dark subterminal band on tertial or tertial coverts, and (5) remnants of alternate or juvenile plumage on the belly. Our results demonstrate that the pattern of white fringes on the inner primary coverts is an important character for ageing Dunlin along the East Asian-Australasian Flyway. In addition, we found that all characteristics used for ageing fade with time, and that breeding adults along the East Asian-Australasian Flyway are more difficult to age than adults elsewhere, in part due to the presence of "adult buff" coverts (ABCs) and in part because of the early timing of primary molt. Finally, we suggest that the presence of ABCs might be useful for differentiating the two Dunlin subspecies (C. a. arcticola and C. a. pacifica) occurring in Alaska. RESUMEN. Diferencias en el plumaje relacionadas a la edad de individuos de Calidris alpina a lo largo de la ruta de vuelo Asiática-AustralianaPara algunas poblaciones del chorlo Calidris alpina, el determinar la edad de los individuos en lasáreas en donde no se reproducen puede ser difícil. Esta dificultad se debe en parte a que algunas poblaciones llevan a cabo la muda de sus primarias durante el verano boreal, dejando a los adultos y los individuos de primer año con una cantidad similar de abrasiones en sus primarias. El determinar la edad de estos chorlos se complica por la presencia de adultos con franjas de "color crema" (buff ) en el borde de las cobijas medias interiores, lo que a menudo es utilizado para determinar la edad de los juveniles. Examinamos un número de característicasútiles (para determinar la edad de los chorlos), para determinar la edad de los pájaros enáreas no reproductivas, a lo largo de la ruta de vuelo Asiática-Australiana. Entre las características encontramos: 1) un patrón de borde blanco de las cobijas internas de las primarias, 2) el color del borde de las cobijas medias interiores, 3) el color de la punta de las cobijas carpales, 4) la presencia o ausencia de una banda oscura subterminal en las cobijas terciarias, y 5) el remanente de plumaje alterno o juvenil en el abdomen. Nuestros resultados muestran que el patrón de bordes blancos en las cobijas internas de las primarias es una característica imp...

Perovskite CsPbI3 quantum dots (QDs) were synthesized as a hole-transporting layer (HTL) of a planar perovskite solar cell (PSC). By using the Octam solution during the ligand engineering, CsPbI3 QDs exhibits a denser grain and a larger grain size due to the short-chain ligands of Octam. In addition, CsPbI3 QDs with the Octam solution showed a smooth and uniform surface on MAPbI3 film, indicating the QDs improved the microstructure of the MAPbI3 perovskite film. As a result, the PSC with CsPbI3 QDs as an HTL has the optimal open-circuit voltage as 1.09 V, the short-circuit current as 20.5 mA/cm2, and the fill factor (FF) as 75.7%, and the power conversion efficiency (PCE) as 17.0%. Hence, it is inferred that introducing QDs as a HTL via the ligand engineering can effectively improve the device performance of the PSC.

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