I would have thought regular on passage?
30 years ago there used to be only very small numbers of White Storks wintering in Iberia. The growth in open landfills with the associated junk food has meant there are now in excess of 15k
Presumably Black Storks now winter in small numbers.....
All this will probably change in the near future as EU legislation means changes in the way open tips operate and no more ‘organic’ waste. The same EU that made people remove dead farm animals thus depriving the natural dustmen, the scavenging Vultures, of traditional food. Of course this doesn’t affect us here in Blighty. Not because we don’t have either Storks or Vultures - because EU subsidies and the CAP has devastated the UK’s wildlife