There's lots of confusion on this story, storks are currently migrating in quite large numbers in Europe, and they fly quite low, so they would normally be arriving in Africa now, however:-
"since the mid 1980s increasing numbers of storks have stopped their annual migration from Northern Europe to Africa for the winter.
Instead, many are living in Spain and Portugal the whole year round -- feeding on 'junk food' from rubbish dumps"
AND
"The average journey south takes 49 days and almost 20,000 km. This stork species sets out from Europe and moves over the Strait of Gibraltar into the Sahara desert, following the heavy thermal systems that allow it to efficiently soar to its destination.
These flocks, some with almost 11,000 individuals, then follow the Nile River south to eventually settle in various African countries, including Kenya Sudan, and S Africa.
The reports on AVH say the birds swallowed were nothing like a stork.
An Egret is a bird very similar to a Heron, we have them in our local lake.
https://en.wikipedia.org/wiki/Egret