Yesterday, Nuqdah left the Caspian Sea and arrived in Siberia. This means that all birds now have left their stopover place in the Caspian Sea or Aral Sea (except Masirah who still enjoys the Omani sun). So time to recapitulate a bit and look at their stopover behaviour.
It appears that there is a strong positive relation between the arrival and departure date in the Caspian/Aral Sea, i.e. birds that arrived late departed late. This probably means that birds face some constrains in this area, for instance they might need a certain amount of time for fattening up before they can make their final jump to the breeding areas. Interestingly, the two birds that made a stopover in the Aral Sea are a bit of an outlier. It is not easy to interpret this at this stage with such a low sample size, but it might mean that there is something odd with the Aral Sea or with the birds that visited this area.