Sex-specific plasticity in Alpine ibex migration timing.

Research Highlight: Chauveau, V., Garel, M., Toïgo, C., Anderwald, P., Apollonio, M., Bassano, B., Beurier, M., Bouche, M., Brambilla, A., Brivio, F., Bunz, Y., Cagnacci, F., Canut, M., Cavailhes, J., Champly, I., Filli, F., Frey-Roos, A., Gressmann, G., Grignolio, S., Herfindal, I., Jurgeit, F., Martinelli, L., Maurino, L., Papet, R., Petit, E., Ramanzin, M., Semenzato, P., Vannard, E., Coulon, A., Loison, A. and Marchand, P. (2025). It's time to go-Drivers and plasticity of migration phenology in a short-distance migratory ungulate. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.70031. Timing strongly influences the benefits animals derive from migration, particularly in herbivores that track vegetation phenology. Yet, despite increasing environmental variability under climate change, little research has focused on the plasticity of individuals' migration decisions and the population-level consequences of such adaptations. Chauveau et al. (2025) investigate the environmental drivers and sex-specific plasticity of migration timing in Alpine ibex (Capra ibex) by integrating long-term movement data from 17 populations, with a particular focus on individual variation. They find that males exhibit greater behavioural plasticity than females, especially in springs with unusually early or late peaks in vegetation green-up. The reduced plasticity in females' spring migration departure is suggested to arise from trade-offs between access to forage and predation avoidance. Interestingly, this difference disappeared when analysis was restricted to repeat migrants, with both sexes performing similarly well, challenging assumptions about fixed reproductive constraints on migratory plasticity. Instead, the patterns reported by Chauveau et al. (2025) seem to point towards a more complex combination of factors underlying migratory plasticity, including reproductive status, experience, social environment and susceptibility to heat stress. These results underscore the importance of long-term, individual-level monitoring to assess migratory patterns and plasticity. Chauveau and colleagues' work lays the foundation for a more nuanced understanding of migration, highlighting how individual traits and behavioural plasticity shape adaptive responses to shifting environmental conditions. Understanding individual behavioural variation may be key to assessing population resilience in the face of rapidly changing environmental conditions.