This weekend I found a Natrix in Belgium, Limburg, Maasmechelen. This is a location where Natrix is not native. After a few mails I know that in 2004 there were 2 Natrix released in a factory that makes fertilizer. They import a lot of horse manure. They came from Schwalmtal, Germany.
Which subspecies lifes here. Is this natrix or helveticus, or something in between?
Peter