In ornithology, the long-distance migration of juvenile birds has remained a challenging area of research. Take the Eurasian Whimbrel (Numenius phaeopus), for instance. While scientists have extensively tracked the global migration patterns of adult whimbrels, accumulating a wealth of data, information about juveniles has been exceedingly scarce.
Past studies have shown that adult whimbrels display different migration strategies during the breeding season in April and May when travelling from their wintering grounds to their breeding sites. Some directly fly to Iceland, while others break their journey into two segments with a stopover. Later, from late July through August, most adult whimbrels fly directly to their wintering grounds in West Africa. However, critical information about juveniles—such as their migratory routes and timing—has long remained a mystery, particularly during their first-ever migration.
In a recent study, an Icelandic research team employed two lightweight tracking devices developed by Global Messenger, models HQBG0804 (4.5g) and HQBG1206 (6g), to monitor 13 juvenile whimbrels. The results revealed intriguing similarities and differences between juvenile and adult whimbrels during their initial migration to West Africa.
Like adults, many juvenile whimbrels managed the impressive feat of flying nonstop from Iceland to West Africa. However, distinct differences were also observed. Juveniles typically embarked later in the season than adults and were less likely to follow a straight migratory route. Instead, they stopped more frequently along the way and flew comparatively slower. Thanks to Global Messenger’s trackers, the Icelandic team captured, for the first time, the nonstop migration journey of juvenile whimbrels from Iceland to West Africa, providing invaluable data for understanding juvenile migration behaviour.
Figure: Comparison of flight patterns between adult and juvenile Eurasian whimbrels. Panel a. adult whimbrels, panel b. Juveniles.
Post time: Dec-06-2024
