The H5N1 strain of avian influenza is sweeping across the world, killing millions of birds. In the UK, it’s causing disastrous losses of seabirds – populations that were already being hit by a number of threats, including habitat loss, overfishing and global heating. Biodiversity reporter Phoebe Weston tells Madeleine Finlay about how the virus made it into wild birds, why it’s having such a devastating impact, and the long-term impact bird flu could have on some of our most vulnerable species. Help support our independent journalism at theguardian.com/sciencepod