They are fed at 14:30 if I remember correctly, but this is also indicated on the map you get on the entrance. They got active half an hour before feeding and even 1,5 hours after the feeding, there was still one outside. So they were quite easy to see at my last visit. In 2012 when there was no such feeding time, we did not see them at all, during several return visits to the enclosure...
Strangely this is one taxon I have never had trouble seeing when I visited Tierpark in 2014 they were asleep in the middle of their enclosure, for instance.
I had no trouble seeing these when I visited Berlin Tierpark just over a week ago either. I saw two, even without it being around feeding (which I didn't actually know about to be honest).
