An internal-combustion engine needs four things to run. They need fuel, mixed with air, in a ratio of 14.7 to one. An ignition-spark lights the fuel and air mixture, creating combustion. Compression of the fuel and air mixture makes it explosive. The final necessity is proper timing, of the components.
1 The length of time it takes for eggs to hatch after incubation begins depends on the species and temperatures. 2  For bluebirds, it USUALLY takes about 12-14 days from the date the last egg was laid.3  Different species have different incubation periods, which can vary within a species due to temperature inside the nestbox. Depending on when incubation begins (on the last, or next to last egg), eggs in the same nest can hatch a day or several days apart. 2  It also takes a while for the bird to break through the shell. 3  It could be a new egg from a subsequent nesting if you didn't clean the box out immediately after the last fledging.
The nest can be found 5-25 feet above the ground, often in the crotch of a shrub or tree. Laying 2 white eggs that are incubated for 14-15 days. The young will leave the nest in 12-14 days.They have been known to reuse the same nest for five sets of eggs in a single season. Usually 2 - 3 broods raised each season.aying 2 white eggs that are incubated for 14-15 days. The young will leave the nest in 12-14 days. They have been known to reuse the same nest for five sets of eggs in a single season. Usually 2 - 3 broods raised each season.