Name: Kurt Woodbridge , Va (Zone 7a) Jai guru deva om
I would definitely remove the nest before any eggs are laid and maybe take the cactus away from the wrens for a couple days. If you could maybe put the nest in a similar container and set it close to the old nest spot.
A pint can't hold a quart , If it is holding a pint it is doing the best that it can.
and it is written ,
if the evil spirit arms the tiger with claws , brahman provided wings for the dove.