diff --git a/timestream.lua b/timestream.lua
index 89ee941f6..bf69f2a47 100644
--- a/timestream.lua
+++ b/timestream.lua
@@ -100,7 +100,9 @@ end
 local function check_new_unit(unit_id)
     local unit = df.unit.find(unit_id)
     if not unit then return end
-    print('registering new unit', unit.id, dfhack.units.getReadableName(unit))
+    if DEBUG >= 3 then
+        print('registering new unit', unit.id, dfhack.units.getReadableName(unit))
+    end
     register_birthday(unit)
 end