diff --git a/parsers/caves.py b/parsers/caves.py
index 426eb437..1bbfe042 100644
--- a/parsers/caves.py
+++ b/parsers/caves.py
@@ -619,7 +619,8 @@ def make_cave(slug):
         for k in kaves:
             if k.slug() is not None:
                 print(" ! - OVERWRITING this one: slug:" + str(k.slug()))
-                k.notes = "DUPLICATE kataster number found on import. Please fix\n" + k.notes
+                current_notes = k.notes or ""
+                k.notes = "DUPLICATE kataster number found on import. Please fix\n" + current_notes
                 cave = k
     return cave