Looks like Cowboy's and Kate's first nest has failed. They appear to have fully abandonned their lone egg. The egg was confirmed last Wednesday and was at least the second egg laid. Now they are back to their routine when they first arrived, hanging out at all their favourite places but HSC in particular. So don't know if they are revving up for a second attempt or not - and yes, there still is time for a renest, particularly since they appear to have lost their nest in the early stages. And because we don't know them, can't even gauge what they might do based on their behaviour.
We're back to waiting and watching again folks.