Along the longest of ways. Tracking 10 gram songbirds from eastern Siberia to southern Africa

Adult male willow warbler

Willow warbler (Phylloscopus trochilus) is the most common breeding bird species in Sweden. Globally its distribution range spans from coast of Atlantic to Pacific ocean. Species is currently split in three subspecies mainly due to differences in migration behaviour. North Scandinavian P. t. acredula migrates SSW to east Africa, central European/southern Scandinavian P. t. trochilus migrates SSE to western Africa. Far NE P. t. yakutensis hypothetically migrate SWS to southern Africa. This might be longest passerine migration on planet.

 

Me in the field with freshly caught dusky warbler female (Phyllsocopus fuscatus)

June and July this summer I spent on expedition to Chaun field station in arctic Russia (68.81 N, 170.62 E). I collected blood and feather samples as well as morphological measurements, phenotype data and some ecological information (clutch size, phenology, breeding density) of P.t.yakutensis breeding there. Importantly I fitted 28 geolocators on adult male willow warblers who were breeding in Chaun delta. Next year I will return to very same study site and try to find returning birds and hopefully document this remarkable migratory trip. Many thanks to Prof. Staffan Bensch, Prof, Susanne Åkesson and Dr Diana Solovyeva for making this project possible.

Researchers and students at Chaun field station, summer 2016. From Left to right: Ksenija Alehina, Anastasija Mylnikova, Carly Stransky, Darya Barykina , Tatjana Stepanova, Dr. Diana Solovyeva (director of the station), Prof. Chao Lei, Gleb Danilovich, Kristaps Sokolovskis, Dr. Sergey Vartanyan, Nikolai Lane

 

Typical willow warbler breeding habitat in Chaun river delta.

Comparison of willow warbler subspecies. From left to right: yakutensis, acredula, acredula and trochilus hybrid, trochilus. Yakutensis is alive and was gently placed on back to take this picture before reliesing. Others are stuffed dummies used as reference specimens to score phenotype.

Adult male willow warbler with geolocator

//Kristaps Sokolovskis