The great tit has a typical lifespan ranging from 11 years and 7 months to 19 years and 3 months, although the maximum recorded lifespan is 15 years and 5 months, with a theoretical lifespan between 10 years and 7 months and 15 years and 1 month. Sexual maturity is reached at an age ranging from 2 months and 1 week to 1 year and 1 month. The "Embryo" stage involves the developing embryo receiving nutrients from the yolk while inside an egg. Following this, the "Nestling" stage sees the young bird in a nest, being fed caterpillars and insects by its parents for a duration of between 2 weeks and 4 days and 3 weeks and 1 day. The "Rapid Growth Post-Fledging Juvenile" stage occurs when the young bird leaves the nest, learning to fly and forage independently for between 1 and 3 months. The “Adult” stage begins when the bird is capable of reproduction, occupying a territory, and raising offspring, lasting from 1 to 10 years.