The industrious female kept showing up with astonishing amounts of building material. Here she is with a beak full of pine needles.
Here she is again, carting in a bunch of oxalis stems and a dead leaf.
The male brought food to his mate and kept watch from the top of the tree for potential hazards.
The neighborhood fox squirrel was the biggest threat.
He lurked like a kind of rodent Godzilla, but never managed to break into the nest. Here's how he looked to the bluebirds. Not remotely cute and furry.
Once the eggs hatched, the nest became a hive of activity, with both parents swooping in and out all day long with insects for their brood.
That caterpillar went straight into the open beak of a hungry nestling.
As the chicks neared fledging day they became increasingly noisy and active, peering out of their front door and chattering to each other.