Final in the Eastern Bluebird/Tree Swallow series. Three images. (See previous four postings for full series/story)
First: Tree Swallow keeping a watchfull eye as it checks out the adjacent Bluebird box.
Bluebird checking out the adjacent nest box after chasing away the Swallow whilst, at all times, keeping a look-out over his shoulder. Note, the Bluebird actually entered the box and threw out some nesting material which presumably had been put there by the Swallow.
Male Bluebird back on guard duty, beautifully perched about 3 meters from the nest box.