You have picked one of their favourite possies straight off, Focus. They use open areas at the based of walls where the grass is a bit longer and affords cover. They will crawl up the wall to get sun but usually not too far away from cover. Not only do both species co-exist, they also share communal egg-laying sites. The maximum clutch is 4 or 5 eggs and up to 130 eggs have been found in the one spot. Not bad even if they do double clutch in a season.
They have long been called garden or grass skinks. They are more common in cities than they are in their natural habitat. They like sunny places that are fairly moist. That would mean forests in nature but getting the sun restricts them to margins and openings in the forest, such as those due to exposed rock shelves. Cultivated garden and lawns provide the ideal combination of conditions.
There is has recently been a move to name delicata the Grass Skink and guichenotia the Garden Skink. In New Zealand, where delicata has become naturalised, it is referred to as the Rainbow Skink, while in Hawaii, where it has been establish for over a century, it is most often referred to as the Metallic Skink.
I am not sure what conditions favour which but growing up in Sydney, where we were giuchenotia were more common. Delicata were more coppery in colour, especially the hatchlings. Individuals do vary a bit in colour and pattern. I have a feeling the male guichenotia develop quite a coppery colour to their head come breeding season - however it has been a long time, so don’t quote me. Looks like a gravid female in the photo, by the way.
I hope that fills in a few blanks for you.
Blue
