The following observations are based on personal experiences of watching bluebirds in nesting boxes on our patio, rather than from a biologist:

The nesting process for bluebirds typically begins about a week before the eggs are laid. Suppose I am observing a pair of bluebirds on our patio starting from Monday. During this time, both the male and female birds are active, going in and out of the nesting box. However, only the female brings materials for nest construction, while the male accompanies her. It seems like she has the final say in choosing the “paint colors” for the nest. This behavior continues until approximately Friday.

Around Saturday, the female bird disappears, indicating that she is laying the eggs. This phase continues until Sunday or Monday. After that, the female emerges from the nest, and both the male and female birds engage in feeding activities until about Wednesday. Then, on Thursday or thereabouts, the female disappears again, returning to the nest and remaining there for another week or 10 days, until the following Saturday.

So, from the start of nest building to hatching, the process takes approximately three weeks. Feeding the chicks takes another ten days to two weeks. During this time, the male and female birds tirelessly go in and out of the nesting box, showing frantic activity. Eventually, one day, they all vanish, indicating that the chicks have fledged. Although we always hope to witness this event, we often miss it.

Overall, the duration from nest building to fledging is approximately four to five weeks, during which the male and female bluebirds never seem to rest, constantly tending to their nesting duties. They repeat this process twice during the spring season. At other times, they do not return to the nesting box but rather flutter around the property, simply being bluebirds.

Please note that the above information is based on personal observations and may not be sourced from authoritative references.