The gadfly petrels or Pterodroma are a genus of about 35 species of petrels, part of the seabird order Procellariiformes. The gadfly petrels are named for their speedy weaving flight, as if evading gadflies (horseflies). The flight action is also reflected in the name Pterodroma, from Ancient Greek pteron, "wing" and dromos, "runner".

The magenta petrel, or Chatham Island tāiko, is a small seabird in the gadfly petrel genus, Pterodroma. Found exclusively on Chatham Island, New Zealand, it is one of the rarest birds in the world, believed to be extinct for over 100 years before its rediscovery in the 1970s.