Agreement on the Conservation of Albatrosses and Petrels

Are you relaxed? Cory’s Shearwater stress levels differ between male migrants and residents

corys shearwater paulo catry 

Cory's Shearwater, photograph by Paulo Catry

Marie Claire Gatt (Centro de Estudos do Ambiente e do Mar, Universidade de Lisboa, Portugal) and colleagues have published in the Journal of Avian Biology on the temperament of breeding Cory's Shearwaters Calonectris borealis (Least Concern).

The paper’s abstract follows:

“Inter‐individual variation in behaviour has been recognised as a major driver of population ecology, but its relationship to migratory strategy has been ill‐explored. Here, we investigated whether male migrant and resident Cory's shearwaters Calonectris borealis, a long‐lived partially migratory seabird, are distinguishable by their temperament at the colony. We tracked a large number of individuals over two winters using GLS devices and assessed whether exploratory behaviour and reaction to extraction from the nest corresponded to migratory strategy over this period. While exploratory behaviour was unrelated to migratory strategy, birds that were resident were more likely to be unreactive towards extraction from the nest. This difference in behavioural stress response, together with previous findings that migrants display higher physiological stress over winter, suggests that migrants and residents may be distinguishable by their stress threshold.”


Gatt, M.-C., Granadeiro, J.P. & Catry, P. 2021.  Migrants and residents of a long‐lived seabird differ in their behavioural response to a stressor.  Journal of Avian Biology 52(2) .

John Cooper, ACAP Information Officer, 14 March 2021