Seasonal distributions of Swedish Caspian terns
The paper was published in a journal "Ringing & Migration” in July. The authors reported recoveries and resighting of Caspian terns Hydroprogne caspia ringed in Sweden since 1920s. This great dataset including more than 2,000 recoveries was provided by the Swedish Ringing Centre at the Natural History Museum in Stockholm.
This study aimed (1) to identify areas of importance during their migration and wintering, (2) to investigate the annual routines of migration and wintering of different age categories, and (3) to investigate how human activities, especially shooting, have affected survival of Caspian Terns over the 80-year period.
Ring recoveries beyond the breeding areas were widely dispersed southward but concentrated in several locations, such as coastal areas in the Netherlands, Italy and Germany during migration seasons and in Mali and Tunisia during winter. Distances to their wintering areas of up to more than 6,000 km were longer than for other populations of this species. I am interested in how this difference affects the migration schedule, number of individuals and morphology in each breeding population. To know more details about their annual movements, we are now trying to track them with GPS data loggers.
Kozue Shiomi, Ulrik Lötberg & Susanne Åkesson (2015) Seasonal distributions of Caspian Terns Hydroprogne caspia from Swedish populations, revealed by recoveries and resightings of ringed birds, Ringing & Migration, 30:1, 22-36, DOI: 10.1080/03078698.2015.1059637
Text and photo by Kozue Shiomi.