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Abstract

We used light-level-based geolocation to study the spatio-temporal behaviour of Siberian Rubythroats Calliope calliope breeding in the Amur region of the Russian Far East. Three retrieved devices revealed long-distance migrations, with southwestward movement from Amur through Northeast China in autumn, with the tracked individuals reaching their wintering grounds in southern China and Indochina without major detours and apparently on a route slightly further west than that of the return migration in spring. A single stopover occurred in two of the three birds in both spring and autumn in China. Migration was faster in spring compared to autumn. The birds spent most of their time in seasonal habitats on their temperate breeding sites, and in less seasonal habitats on their tropical wintering grounds. Departure from and arrival at their breeding site coincided with decreasing and increasing vegetation greenness, respectively. This is the first study presenting year-round tracking data for a songbird migrating from mainland Eurasia to Southeast Asia along the East Asian flyway.
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... Rubythroats are known to spend the non-breeding season in coastal areas and islands of East Asia, in South-East Asia, and eastern India [18]. Previous tracking of one of its breeding population from the Russian Far East suggested a rather direct migration route passing through central China towards mainland South-East Asia, thereby largely following the East Asia-Australasia Flyway (EAAF) [27,28]. However, nothing is known regarding the migration patterns of an isolated breeding population on highlands of central China. ...
... From an evolutionary perspective, the faithfulness towards the wintering ground in SE Asia may also contribute to the shape of the autumn route. The Siberian Rubythroat population breeding in the Russian Far East migrates to non-breeding areas in SE Asia, whereas the breeding population from Hokkaido, Japan, and Kamchatka, Russia, has been shown to spend the non-breeding season in coastal/islandic areas along western Pacific Ocean, as revealed by tracking and ringing data [27,28]. From a phylogenetic perspective, the population from the Russian Far East is more closely related with the central China population [73]. ...
... The fast journey and earlier arrival can be beneficial to a higher fitness during the breeding phase, e.g., to allow the birds to be more competitive among males and favored by females at the breeding site [40,65,66,70]. In addition, Siberian Rubythroats are highly faithful to their breeding territory ( [28], Zhao, personal observational data). An early arrival at the breeding site will allow the birds to occupy their previous territories before it is taken by e.g. ...
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Background Small songbirds respond and adapt to various geographical barriers during their annual migration. Global flyways reveal the diverse migration strategies in response to different geographical barriers, among which are high-elevation plateaus. However, few studies have been focused on the largest and highest plateau in the world, the Qinghai–Tibet Plateau (QTP) which poses a significant barrier to migratory passerines. The present study explored the annual migration routes and strategies of a population of Siberian Rubythroats (Calliope calliope) that breed on the north-eastern edge of the QTP. Methods Over the period from 2021 to 2023, we applied light-level geolocators (13 deployed, seven recollected), archival GPS tags (45 deployed, 17 recollected), and CAnMove multi-sensor loggers (with barometer, accelerometer, thermometer, and light sensor, 20 deployed, six recollected) to adult males from the breeding population of Siberian Rubythroat on the QTP. Here we describe the migratory routes and phenology extracted or inferred from the GPS and multi-sensor logger data, and used a combination of accelerometric and barometric data to describe the elevational migration pattern, flight altitude, and flight duration. All light-level geolocators failed to collect suitable data. Results Both GPS locations and positions derived from pressure-based inference revealed that during autumn, the migration route detoured from the bee-line between breeding and wintering grounds, leading to a gradual elevational decrease. The spring route was more direct, with more flights over mountainous areas in western China. This different migration route during spring probably reflects a strategy for faster migration, which corresponds with more frequent long nocturnal migration flights and shorter stopovers during spring migration than in autumn. The average flight altitude (1856 ± 781 m above sea level) was correlated with ground elevation but did not differ between the seasons. Conclusions Our finding indicates strong, season-dependent impact of the Qinghai–Tibet Plateau on shaping passerine migration strategies. We hereby call for more attention to the unexplored central-China flyway to extend our knowledge on the environment-migration interaction among small passerines.
... Apart from the widely-applied Light-level geolocator (GL) method, the minimized archival GPS technology and the advanced analysis of data from multi-sensor miniature loggers also thrived in the past decade, assisting ornithologists to acquire highly precise migration patterns of small songbirds ( The Siberian Rubythroat (Calliope calliope) is a small songbird that has a wide breeding range in northern Asia, and is known to spend the nonbreeding season in South-East Asia (Collar, 2020). Previous tracking of a breeding population from the Russian Far East suggested a rather direct migration route passing through central China towards mainland South-East Asia, thereby largely following the East Asia -Australasia Flyway (EAAF) (Heim et al., 2018(Heim et al., , 2020. However, nothing is known regarding the migration patterns of an isolated breeding population on highlands of central China: it is sometimes recognized as a separate subspecies Calliope calliope beicki (Spiridonova et al., 2017;Stresemann et al., 1937), but has no known morphological differences compared to other populations (Collar, 2020). ...
... From an evolutionary perspective, the faithfulness towards the wintering ground in SE Asia may also contribute to the shape of the autumn route. The Siberian rubythroat population breeding in the Russian Far East migrates to non-breeding areas in SE Asia, whereas the breeding population from Hokkaido, Japan, and Kamchatka, Russia, has been shown to spend the non-breeding season in coastal/islandic area along western Paci c Ocean, as revealed by tracking and ringing data (Heim et al., 2018(Heim et al., , 2020. From the demographic perspective, the population from the Russian Far East is more closely related with the central China population (Spiridonova et al., 2017). ...
... There hasn't been any clear de nition regarding the boundary between these two yways; it has been argued that the eastern QTP yway could treated as an independent yway from either EAAF for CAF (Kumar et al., 2020). The autumn migration tracks of Siberian Rubythroats from our dataset clearly illustrated an avoidance pattern to the confrontation to QTP, differed from the migrants from eastern Asia (Heim et al., 2018(Heim et al., , 2020. This indicates that a differential selection force due to the different landscape patterns along the two routes used by the two different geographical populations. ...
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Background Small songbirds respond and adapt to various geographical barriers during their annual migration. Global flyways reveal the various migration strategies in response to different geographical barriers, among which are high-elevation plateaus. However, few studies have been focused on the largest and highest plateau in the world, the Qinghai-Tibet Plateau (QTP) which poses a significant barrier to migratory passerines. The present study explored the annual migration routes and strategies of a population of Siberian Rubythroats (Calliope calliope) that breed on the north-eastern edge of the QTP. Methods Over the period from 2021 to 2023, we applied light-level geolocators (n = 13), archival GPS tags (n = 45), and CAnMove multi-sensor loggers (with barometer, accelerometer, thermometer, and light sensor, n = 20) to the breeding population of Siberian rubythroat on QTP. Here we describe the migratory routes and phenology extracted or inferred from the logger data, and used a combination of accelerometric and barometric data to describe the elevational migration pattern, flight altitude, and flight duration. Results Both GPS locations and positions derived from pressure-based inference both revealed that during autumn, the migration route detoured from the bee-line between breeding and wintering grounds, leading to a gradual elevational decrease. The spring route was more direct, with more flights over mountainous areas in western China. This different migration route during spring probably reflects a strategy for a faster migration, which corresponds with more frequent long nocturnal migration flights and shorter stopovers during spring migration than in autumn. The average flight altitude (2000 m above sea level) was correlated with ground elevation but did not differ between the seasons. Conclusions Our finding indicates the strong impact of the Qinghai-Tibet Plateau on shaping passerine migration strategies. We hereby call for more attention to the unexplored central-China flyway to extend our knowledge on the environment-migration interaction among small passerines.
... Different flying animals, such as birds, bats, and insects, play crucial roles in our ecosystems as they contribute to pollination, seed dispersal, pest control, and nutrient cycling [1], [2], [3], [4]. In some cases, they may also be considered as pests that are detrimental to an ecosystem, such as an agricultural ecosystem (e.g. ...
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Detecting flying animals (e.g., birds, bats, and insects) using weather radar helps gain insights into animal movement and migration patterns, aids in management efforts (such as biosecurity) and enhances our understanding of the ecosystem.The conventional approach to detecting animals in weather radar involves thresholding: defining and applying thresholds for the radar variables, based on expert opinion. More recently, Deep Learning approaches have been shown to provide improved performance in detection. However, obtaining sufficient labelled weather radar data for flying animals to build learning-based models is time-consuming and labor-intensive. To address the challenge of data labelling, we propose a self-supervised learning method for detecting animal movement. In our proposed method, we pre-train our model on a large dataset with noisy labels produced by a threshold approach. The key advantage is that the pre-trained dataset size is limited only by the number of radar images available. We then fine-tune the model on a small human-labelled dataset. Our experiments on Australian weather radar data for waterbird segmentation show that the proposed method outperforms the current state-of-the art approach by 43.53% in the dice co-efficient statistic.
... Overall, our data suggest that the tracked Arctic Warbler was almost constantly on the move, not a single site during the annual cycle has been used for more than two months. This differs strongly from other East Asian songbird migrants, for which long autumn stopovers of up to three months and very long stationary periods during the boreal winter (five to six months) were documented (Heim et al. 2018(Heim et al. , 2020. Most likely, Arctic Warblers are moving further to track seasonal peaks of food abundance-a similar pattern with several consecutive wintering sites was found in the closely related Willow Warbler Phylloscopus trochilus wintering in Africa (Lerche-Jørgensen et al. 2017;Sokolovskis et al. 2018). ...
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Little is known regarding the migration routes of Siberian songbird populations. Here we provide the first geolocator tracking data for an Arctic Warbler breeding in Central Siberia and compare its movements with eight long-distance ring recoveries of this species. In autumn, the tracked individual migrated eastward to a stopover site in eastern Siberia, before migrating southward through Taiwan to its non-breeding sites in the Philippines and Indonesia. During spring migration, the bird spent at least one month at stopover sites in Mongolia, before migrating to its breeding site in June. Ring recovery data confirmed the movement between the Central Siberian breeding grounds and stopover sites in northern Mongolia.
... However, our data here is Overall, our data suggests that the tracked Arctic Warbler was almost constantly on the move, not a single site during the annual cycle has been used for more than two months. This differs strongly from other East Asian songbird migrants, for which long autumn stopovers of up to three months and very long stationary periods during the boreal winter ( ve-six months) were documented (Heim et al. 2018(Heim et al. , 2020 Fig. 1) might also relate to the constant movement of the tracked bird, but they could also stem from high levels of shading in the understorey of tropical forests which would affect the accuracy of the position estimation (Lisovski et al. 2012). ...
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Little is known regarding the migration routes of songbird populations breeding in Siberia. Here we provide the first geolocator tracking data for an Arctic Warbler breeding in Central Siberia and compare its movements with eight long-distance ring recoveries of this species. In autumn, the tracked individual migrated eastward to a stopover site in eastern Siberia, before migrating southward through Taiwan to its non-breeding sites in the Philippines and Indonesia. During spring migration, the bird spent at least one month at stopover sites in Mongolia, before migrating to its breeding site in June. Ring recovery data confirmed the movement between the Central Siberian breeding grounds and stopover sites in northern Mongolia.
... In the EAF, very few studies of migratory connectivity in migratory forest breeding birds have been conducted. An exception is a recent study on the Siberian Rubythroat (Luscinia calliope), which is a shrubland breeding migratory species also seeming to show low migratory connectivity 40 . However, as such information is still largely lacking, this limitation further supports the need for more studies in the wintering range of migratory landbirds in the EAF. ...
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The East Asian Flyway (EAF) is the most species diverse of global flyways, with deforestation in its migratory landbird’s non-breeding range suspected to be the main driver of population decline. Yet range-wide habitat loss impact assessments on EAF migratory landbirds are scarce, and seasonal variation in habitat preference of migratory species further increases the complexity for conservation strategies. In this study, we reviewed population trends of migratory forest breeding birds in the EAF along with their seasonal habitat preference from the literature and assessed the impact of forest cover change in species’ breeding and non-breeding ranges on population trends. We found that 41.3% of the bird species with trend data available are declining, and most have higher forest preference in the breeding season. Despite 93.4% of the species experienced deforestation throughout their annual cycle, forest cover change in the non-breeding range was not identified as the main driver of population trend. However, forest cover change in species’ regional breeding range interacts positively with the degree of breeding season forest preference in predicting population trends. We therefore stress that regional breeding habitat protection may still be important while following the call for cross-border collaboration to fill the information gap for flyway conservation.
... Other recent studies also demonstrated that northern populations of the species are migratory (Choi, Nam, Kim, et al., 2020;Choi, Nam, Park, & Bing, 2020;Zhang et al., 2023). All individuals migrated south-westward during autumn to nonbreeding sites on the East Asian mainland, a pattern observed in the majority of migratory East Asian songbird species (Bensch et al., 2022;Heim, Heim, Beermann, et al., 2020;Heim, Pedersen, et al., 2018;Yamaura et al., 2017). An exception to this pattern is the Blue-and-white Flycatchers Cyanoptila cyanomelana co-occurring with yellow-throated buntings at our study site, which TA B L E 2 Migration timing and nonbreeding locations estimated based on light-level geolocation data for six individual yellow-throated buntings breeding at Khingansky state nature reserve, Russia. ...
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