Breeding Double Barred Finches as a colony on their own.

[monotwine]

My only problem with the DB's have been that I find the males very territorial.

If their nests are too close to another pair or if they can see the other pair from their nest site, they tend to spend more time chasing each other about than giving their ladies attention. Mine don't seem to bother with other species, just each other. Just make sure the pairs have adequate space and try give them hidey hole areas / shrubbery to keep out of view.
Some of my males are real non-quitters when it comes to chasing down another male.