Winter 2002/2003 will be remembered as a black season by those unfortunate enough to become involved in a series of oil spills that killed many tens of thousands of seabirds in West European waters. For most, the Prestige spill was by far the most dramatic event and this incident received most media attention. Overshadowed by the Prestige in many respects, but arguably at least as harmful to European seabirds, was the Tricolor spill that took place in the French Channel. This special issue of Atlantic Seabirds is a summary of what we now know about the seabirds killed: how many were affected, what species and of what age they were and their possible breeding origins. It also contains descriptions of the event that made us wonder why it happened in the first place. It attempts to bring together information vital for a proper evaluation of an oil spill and should provide baseline data for future work. This issue has been produced with greatly appreciated financial support from Vogelbescherming Nederland, the Dutch Birdlife partner. As usual, however, most of the work was done by volunteers at their own expense, people concerned enough to become involved.