Article in journal Report number 197 from Kvismare Bird Observatory: Extreme altitudes during diurnal flights in a nocturnal songbird migrant Sjöberg S, Malmiga G, Nord A, Andersson A, Bäckman J, Tarka M, Willemoes M, Thorup K, Hansson B, Alerstam T & Hasselquist D. Published 2021 in Science, volume 372, pp. 646-648. View article