Data for: Telomere length predicts timing and intensity of migratory behavior in a nomadic songbird

Our understanding of state-dependent behavior is reliant on identifying
physiological indicators of condition. Telomeres are of growing interest
for understanding behavior as they capture differences in biological state
and residual lifespan. To understand the significance of variable telomere
lengths for behavior and test two hypotheses describing the relationship
between telomeres and behavior (i.e., the causation and the selective
adoption hypotheses), we assessed if telomere lengths are longitudinally
repeatable traits related to spring migratory behavior in captive pine
siskins (Spinus pinus). Pine siskins are nomadic songbirds that exhibit
highly flexible, facultative migrations, including a period of spring
nomadism. Captive individuals exhibit extensive variation in spring
migratory restlessness and are an excellent system for mechanistic studies
of migratory behavior. Telomere lengths were found to be significantly
repeatable (R = 0.51) over 4 months, and shorter pre-migratory telomeres
were associated with earlier and more intense expression of spring
nocturnal migratory restlessness. Telomere dynamics did not vary with
migratory behavior. Our results describe the relationship between telomere
length and migratory behavior and provide support for the selective
adoption hypothesis. More broadly, we provide a novel perspective on the
significance of variable telomere lengths for animal behavior and the
timing of annual cycle events.