Authors: Ashley R. Robart, Hilary X. Zuñiga, Guillermo Navarro. and Heather E. Watts
Year: 2022
Publication: Biology Letters
Publication Link: https://royalsocietypublishing.org/doi/10.1098/rsbl.2022.0006
Abstract: The final stage of migration, when animals terminate migratory movements
and transition to a more sedentary state, remains the least understood
phase of migration. Whereas migrants that return to the same locations
each year may use mechanisms associated with locating a specific destination,
migrants with low site fidelity, such as nomadic migrants, may rely
on local environmental cues to determine when to cease migratory movements.
Using an experiment with captive birds, we tested whether the
presence of a conspecific influences the termination of migration, indicated
by changes in behaviour and physiology, in a nomadic migrant (the pine
siskin, Spinus pinus). We paired migratory birds with a non-migratory individual
or left migratory and non-migratory individuals unpaired. Migratory
paired birds had a significant decline in nocturnal activity immediately after
pairing and activity levels remained lower two weeks later, with significant
declines in energetic reserves and flight muscle size also observed. By contrast,
migratory unpaired birds maintained high levels of activity and
energetic reserves. These results provide evidence for a role of the social
environment in migratory termination decisions. Social cues may be particularly
useful in nomadic migrants, such as pine siskins, to facilitate settling in
high quality, but unfamiliar, habitats.