Consistency in long-distance bird migration: Contrasting patterns in time and space for two raptors

• Published in: Animal Behaviour
• Main Authors: Vardanis, Yannis, Nilsson, Jan-Åke, Klaassen, Raymond H. G., Strandberg, Roine, Alerstam, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2016
• Subjects: Zoology; Behavioral Sciences Biology; bird migration; consistency; individual variation; marsh harrier; osprey; satellite telemetry; Pandion haliaetus
• Online Access: https://lup.lub.lu.se/record/5f2e92b7-7b51-4d75-b82f-b4a0bbb22e49; https://doi.org/10.1016/j.anbehav.2015.12.014

As the evolutionary responses to environmental change depend on selection acting on individual differences,disentangling within- and between-individual variation becomes imperative. In animalmigration research, multiyear tracks are thus needed to estimate the individual consistency of phenotypictraits. Avian telemetry studies have recently provided the first evidence of individuality acrossspace and time in animal migration. Here, we compare repeatability patterns of routes and timing betweentwo migratory birds, the marsh harrier, Circus aeruginosus, and the osprey, Pandion haliaetus, asrecorded by satellite tracking. We found interspecific contrasts with low repeatability in timing andduration and a high repeatability in routes for ospreys, but the reverse pattern for marsh harriers. Thiswas mainly caused by (1) larger between-individual variation in routes for ospreys (broad-frontmigration) than for marsh harriers (corridor migration) and a higher degree of repeated use of the samestopover sites among ospreys, and (2) higher within-individual consistency of timing and durationamong marsh harriers, while individual ospreys were more flexible. Our findings suggest that individualityin space and time is not a shared trait complex among migrants, but may show adaptivevariation depending on the species' life history and ecology.