A small, four ounce migratory rufa red knot known as “Moonbird” has been spotted in his wintering grounds of Argentina. Moonbird is the oldest known member of his species being over 20 years old. He was banded with a red tag “B95” in Argentina in 1995 when he was already fully grown. He was given the name Moonbird because, over his lifetime, he has flown more than the distance between the Earth and the moon.
In 2012, a book by Phillip Hoose publicized the story of this remarkable bird and the plight of the rufa red knot, the subspecies of red knot that most frequents the east coast of the United States. Moonbird’s story has further heightened the plight of the subspecies and their reliance on horseshoe crab eggs to sustain their migration. A few years before, PBS Nature had done a story about how humans are affecting the supply of horseshoe crabs in their TV episode “Crash: a Tale of Two Species”. In recent years, the population of rufa red knots has plummeted and the excessive harvesting of horseshoe crabs is suspected to be the cause of their demise. Recently, rufa red knots have been put on the endangered species list giving them special protection.
Very few rufa red knots visit San Diego, so it’s unlikely that Moonbird will ever be seen here. San Diego often hosts roselaari red knots which travel along the west coast and breed in Alaska. Rufa red knots breed in the high arctic islands between Canada and Greenland. Both species look very similar. Though roselaari red knots have shown signs of decline, those declines are not critical to warrant special concern like the rufa red knot. Other red knot subspecies around the world have also not experienced series declines like rufa.
To see Moonbird’s west coast cousins, it is best to visit areas that have mud flats such as those in the South Bay and the Chula Vista Marina or around bays and river mouths. These birds are unlikely to be seen here in San Diego in their full, rusty breeding colors. Instead, they will be gray with chevrons across their chest and most likely have black legs, especially in winter. Young birds and birds transitioning out of breeding plumage may have yellow legs.