Seasonal migration patterns of Siberian Rubythroat (Calliope calliope) facing the Qinghai-Tibet Plateau

Abstract

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.

Keywords: Archival GPS; Central-China flyway; Flight altitude; GeoPressureR; Geographical barriers; Geolocation; Loop migration; Molt migration; Multi-sensor logger.

Fig. 1

Geography of the study area: black lines indicate the borders of the “Three Stairs of China” landscape pattern. The color palette represents the ground elevation. Major landscape elements that potentially function as geographical barriers to migratory landbirds are highlighted on the map. The red star represents the location of the fieldwork for this project

Fig. 2

a–b Migration routes of Siberian Rubythroats from the Qinghai breeding population based on GPS loggers: a. autumn routes (n = 16, note that the route of individual 50012 was not complete, and the route of 50010 was only nearly complete); b. whole-year routes (n = 3). c–d. Migration routes based on CAnMove loggers: c. autumn routes (n = 6); d. spring routes (n = 5). Different colors represent different individuals. The size of the dots represents the relative duration of each stopover (in days). Lines represent the bee-line between each position

Fig. 3

Stopover elevation of Siberian Rubythroats during migration based on CAnMove loggers in a. autumn 2021 and b. spring 2022. The x-axis represents the proportion of the cumulative duration of the journey against the total duration of the journey. The red circle in panel b highlights the passage over the lowland region in the Chengdu Plain. In panel a, data in late autumn are lacking because all loggers were set to stop registering pressure data after November 20th, 2021, when none of the birds had finished autumn migration. We assumed a direct migration path between the last stopover during autumn migration that had pressure data and the wintering location; we used the great-circle distance for this path to complete the calculation of the total autumn migration distance

Fig. 4

Distribution of mean altitude (a.s.l.) of each flight event of the CAnMove logger-tracked Siberian Rubythroats in 2021–2022 (n = 5). The black line indicates the mean flight altitude during both spring and autumn migration

Fig. 5

Annual cycle of Siberian Rubythroats breeding on the Qinghai-Tibet Plateau in a calendar

Fig. 6

Duration of stopover (a–b) and flights (c) derived from the data of the CAnMove loggers: a. Total duration of stopovers in both seasons. b. The distribution of each stopover duration in both seasons; the molting stopovers were not included. c. The distribution of each flight duration (calculated from the adjusted flight hours) in both seasons