Seasonal and daily movement patterns of an alpine passerine suggest high flexibility in relation to environmental conditions

Abstract

Mountains naturally offer variable habitat conditions, but their biodiversity is currently facing the extra challenge of adapting to rapid environmental shifts that are much more pronounced than in the lowlands. Among adaptive responses, intra‐ and inter‐seasonal movements represent potentially important coping strategies for wildlife that remain largely unexplored. We investigated the seasonal and daily movements of the ring ouzel Turdus torquatus, a European mountain bird species that is declining in many parts of its distribution. We tracked individuals breeding in the Swiss Alps using light‐level geolocators and multi‐sensor loggers. Of the birds traced to their non‐breeding grounds, two‐thirds reached the Atlas Mountains while one‐third stayed in Spain, a region potentially more significant for overwintering than previously thought. The birds remained mostly above 1000 m throughout the annual cycle, highlighting a strict association of ring ouzels with mountain habitats. We also evidenced flexible daily elevational movements, especially upon spring arrival on the breeding grounds in relation to date and snowfall occurrence, suggesting adaptive potential in response to environmental variation. This study shows how modern technology can deliver deeper and valuable insights into movements, behavioural patterns and life‐history strategies for relatively little‐studied animal species. By doing so, it paves the way for refined assessments of species' vulnerability to ongoing global change while providing basic conservation guidance.

Variation in Demography and Life-History Strategies Across the Range of a Declining Mountain Bird Species

“…Single brooding in the Alps is probably imposed by the shorter time window with suitable breeding conditions at higher elevations, mediated through prey availability (Boyle et al, 2016;Lundblad and Conway, 2020). In effect, the deep snowpack in the Alps impedes any access to the traditional foraging grounds when birds return from their winter quarters (Barras et al, 2021b), whilst snow is most of the time absent at the same period in the British uplands. Later in the season, the suitability of the Alpine foraging habitat and thereby prey availability decreases rapidly (Barras et al, 2020).…”

Locally adapted migration strategies? Comparing routes and timing of northern wheatears from alpine and lowland European populations

“…In this study, the phenology in spring is more different between individuals of the German low‐land population, although samples size might have been too small for reliable detection. Alternatively, alpine birds might also evade extreme weather events by altitudinal movement (Barras et al 2021). The new development of bio‐logging tools using air pressure might have the potential to reveal such behaviour in the future (Meier et al 2018, Sjöberg et al 2018, Barras et al 2021).…”

“…Alternatively, alpine birds might also evade extreme weather events by altitudinal movement (Barras et al 2021). The new development of bio‐logging tools using air pressure might have the potential to reveal such behaviour in the future (Meier et al 2018, Sjöberg et al 2018, Barras et al 2021).…”

pamlr: A toolbox for analysing animal behaviour using pressure, acceleration, temperature, magnetic or light data in R

“…Actograms are often used to plot activity over time at different hours of the day (Bäckman, Andersson, Pedersen, et al, 2017; Barras et al, 2021; Briedis et al, 2020; Evens et al, 2020). However, the same approach can be used to plot any sensor data, not just activity.…”