I expect that he was speaking in the context of 'in my experience' - meaning what he personally has dealt with out in the field as opposed to what he's read on the internet about other sites.
Madame X and Surge may have a new egg(s) down at the other end of the scrape towards the cam. Can't see the egg but she's been laying on something the past 2 days and nights. The other day Surge dug up an old egg at the regular end so they had buried one of them. I guess he wanted to move it to where the new one is but couldn't figure out how to do that so it's still sitting there.