Dear colleagues, My coauthor, Caroline Weir, and I are pleased to announce the publication of a new study on the vocal behavior of sei whales in the Falkland Islands: Cerchio S, Weir CR. 2022. Mid-frequency song and low-frequency calls of sei whales in the Falkland Islands. R. Soc. Open Sci. 9: 220738. doi: 10.1098/rsos.220738 Abstract: Although sei whales (*Balaenoptera borealis*) are distributed throughout the globe, their behaviour and vocal repertoire are poorly described. We used passive acoustic monitoring to describe the vocal behaviour of sei whales in the Falkland Islands, between December 2018 and April 2019. We isolated more than 2000 low-frequency calls for manual classification, of which 510 calls with high signal-to-noise ratio were quantitatively measured. Five categories of stereotyped call types in the 15–230 Hz range were described, some with multiple subcategories. These included some similar to previously described calls (e.g. downsweeps), but others that were novel in acoustic structure and frequency band. In the mid-frequency range, we documented a highly stereotyped, hierarchically structured and rhythmically repetitive song display. Songs were arranged in phrases with a structure composed of repetitive sub-phrases, and a diverse variety of sounds in the 1–5 kHz range. Singing commenced in late February, despite the presence of whales and calls since early December, and continued through April. These acoustic properties and behavioural characteristics indicate that this is likely a male breeding display similar to songs and singing of other balaenopterids. This is the first detailed description of a song display for sei whales, highlighting the importance of the Falkland Islands. Open access available at: https://royalsocietypublishing.org/doi/10.1098/rsos.220738 The paper includes exemplar audio clips of all described vocalization types in supplemental materials: https://royalsocietypublishing.org/doi/suppl/10.1098/rsos.220738 Best regards, Salvatore -- ********************************** Salvatore Cerchio, Ph.D. African Aquatic Conservation Fund Director, African Cetacean Program africanaquaticconservation.org/programs/african-cetacean-program Facebook: AfricanAquaticConsFund Twitter: @AfricanAquatic and Madagascar Omura's Whale Project www.omuraswhale.org Facebook: MadagascarOmurasWhale Twitter: @OmurasWhale info@omuraswhale.org +1-917-796-3363 (USA mobile) +261-32-25-561-68 (Madagascar mobile) Skype: scerchio_2 Co-Chair, IndoCet, Indian Ocean Network for Cetacean Research, i <http://indocet.org/>ndocet.org <http://indocet.org> Adjunct Scientist, Center for Coastal Studies Visiting Scientist, New England Aquarium