The tail of the bar-tailed godwit is striped like a bar code while the tail of the black-tailed godwit is black. However, that is very difficult to see from a distance, even with a telescope. It's easier to distinguish the two species in the summer, when the male bar-tailed godwit is much redder than the black-tailed godwit. The bar-tailed godwit is smaller and its beak tilts slightly upward. Bar-tailed godwits are champions in migration. Twice a year they fly more than 4000 kilometers between their summer and winter home. The Wadden Sea is a fuel station for these world travelers. This is where they rest and fatten up before moving further.