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Cross the sea where it is narrowest: migrations of Pacific Swifts (Apus pacificus) between Sakhalin (Russia) and Australia


Very few land bird species in the East Asian-Australasian Flyway regularly winter in Australia. One such species is the Pacific Swift Apus pacificus. Using light-level geolocators, we tracked the almost 10,000 km long journey of three individuals between Sakhalin Island (Russia) and Australia. Migrating individuals avoided prolonged sea crossings; both during the southward and northward migrations they performed detours, moving from Sakhalin to the nearest Asian continent (Primorie, Russia), reaching northern Australia via Indochina and the Indonesian archipelago. Southward migration duration was on average 12 days longer than northward migration, although stopover duration did not differ between boreal fall and spring. However, during the northward migration, swifts stopped much closer to the Australian wintering grounds (in Indonesia and around Vietnam) than during the southward migration (Southern China and Vietnam). We suggest that migration to and from Australia is rather challenging for an insectivorous terrestrial bird, particularly during northward migration, requiring adjustment of timing to match contrasting meteorological patterns: the dry season in Northern Australia, the end of the wet season in Indonesia, and the start of the wet season in Indochina. Furthermore, swifts must cope with delayed phenological spring in Northeast Asia, possibly causing them to wait at Southeast Asian stopover sites before rapidly reaching Sakhalin breeding grounds in the early boreal summer.


Quere das Meer, wo es am engsten ist: der Zug des Pazifikseglers ( Apus pacificus ) zwischen Sachalin (Russland) und Australien

Nur sehr wenige Landvögel ziehen entlang des Ostasiatisch-Australischen Zugweges zur Überwinterung bis nach Australien. Eine dieser Arten ist der Pazifiksegler Apus pacificus. Mithilfe von Geolokatoren konnten wir den fast 10 000 km langen Zugweg dreier Individuen von der Insel Sachalin (Russland) bis nach Australien verfolgen. Während des Herbst- und Frühjahrs-Zuges vermieden die Pazifiksegler weite Zugstrecken über das offene Meer. Im Herbst flogen die Vögel von Sachalin auf das nahegelegene Festland, und erreichten das nördliche Australien über Indochina und den indonesischen Archipel. Der Herbstzug dauerte im Durchschnitt 12 Tage länger, wohingegen kein Unterschied in der Rastdauer zwischen Herbst- und Frühjahrszug gefunden werden konnte. Die Rastplätze lagen im Frühjahr näher an Australien (Indonesien und Vietnam) als im Herbst (Süd-China und Vietnam). Wir vermuten, dass der Zugweg nach Australien eine große Herausforderung für insektivore Landvögel ist. Das gilt insbesondere für das Timing des Frühjahrszuges, wenn die Bedingungen entlang der Zugroute sehr unterschiedlich sind: Trockenzeit im nördlichen Australien, das Ende der Regenzeit in Indonesien, und der Beginn der Regenzeit in Indochina. Der sehr spät einsetzende Frühling in Nordost-Asien führt vermutlich dazu, dass die Pazifiksegler an den südostasiatischen Rastplätzen warten müssen, um das Brutgebiet dann mit langen Nonstop-Flügen im zeitigen Sommer zu erreichen.

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Data availability

The data generated during and/or analysed during the current study are available in the Movebank Data Repository,,path=study1454994720, Pacific Swift (Sakhalin – Australia), study ID 1454994720.


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We are thankful to everybody who contributed to trapping of Pacific Swifts in the Schachtersk village. Special thanks are due to Birgita Hansen for austral insights into our boreal perspectives.


OK and PK acknowledge support from the Institute of Biological Problems of the North FEB RAS (registered research project AAAA-A17-117122790002–8). L.G. was supported by the China Thousand Young Talents Program (K18291101), Shenzhen Government (Y01296116), and the High-level Special Funding of the Southern University of Science and Technology (G02296302, G02296402).

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The project was led by PK with critical input from LG. The fieldwork was done by PK and OK. WH analysed the geolocation data. OK performed the statistical analysis. LG provided funding for geolocators. All authors contributed to the drafts and gave final approval for publication. The authors declare no conflict of interest.

Corresponding author

Correspondence to Luke Gibson.

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Communicated by N. Chernetsov.

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Ktitorov, P., Heim, W., Kulikova, O. et al. Cross the sea where it is narrowest: migrations of Pacific Swifts (Apus pacificus) between Sakhalin (Russia) and Australia. J Ornithol 163, 19–26 (2022).

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  • East Asian-Australasian flyway
  • Geolocation
  • Land bird
  • Speed
  • Timing
  • Tracking