Penguins tend to be long-lived as do most seabirds so they may take up to anywhere from three to eight years to reach sexual maturity depending on the species. On average though breeding does not begin until the fifth year of life. Most penguin species have an annual breeding season which is usually spring through summer.

Penguins also tend to be monogamous and mate selection tends to be up to the female. It is the females that compete for the males. If a female chooses another mate it is usually because her previous mate has not returned to the breeding site or they arrive at the site at different times and miss each other.

Penguins also for the most part remain faithful to the same breeding sites or rookeries year after year and many return to the same place that they were hatched. Some rookeries will have up to millions of penguins returning there. It is the males that return first to the rookeries to establish and defend their nesting sites. In many species of penguins it is the males that actually build the nest for the female and most nests are made up of pebbles sometimes lined with feathers.

The following video shows the nest building activity of two male penguins, however one of the penguins is doing all the work while the other one is stealing pebbles from his fellow penguin's nest. All the while the little thief is making sure that no one else follows suit and steals from him. This very human like behavior is quite entertaining to watch - enjoy!