Nuthatches are monogamous, and a pair occupies a breeding territory in which it spends the winter as well.
Territory sizes range from 2–10 ha (5–25 acres) in Europe to an average of 30.2 ha (75 acres) in the sub-optimal conifer forests of Siberia.
The male sings to defend his territory and attract a mate.
Both sexes have a courtship display with a floating, quivering flight, and the male will also make circular flights with a spread tail and raised head.
He will also feed the female while courting her.
Despite the lifelong pairing, genetic research in Germany showed that at least 10% of the young in the study area were fathered by another male, usually from an adjacent territory.

The nest is in a tree cavity, usually an old woodpecker hole, but sometimes of natural origin.
Occasionally the female will enlarge an existing hole in rotten wood.
The nest site is typically 2–20 m (7–66 ft) above the ground and has a deep base of pine bark or chips of other wood, rarely supplemented with dry plant material.
If the entrance to the hole is too large, it is plastered with mud, clay and sometimes dung to make it smaller.
A small entrance and large interior, together with the use of a deep layer of wood chips in which to bury the eggs and small young when the adults leave the nest, may be adaptations to reduce the chance of predation.
Nests with small entrance holes are most successful.
Locally, a small entrance may make it less likely that the nest will be taken over by common starlings.
The female undertakes most of the work, and often plasters the inside of the cavity too, taking up to four weeks to complete the construction.
A nest is often re-used in subsequent years.

The clutch is usually 6–9 red-speckled white eggs, although up to 13 eggs are sometimes laid.
They average 19.5 mm × 14.4 mm (0.77 in × 0.57 in) and weigh 2.3 g (0.081 oz) of which 6% is shell.
The female incubates the eggs for 13–18 days to hatching, and broods the altricial downy chicks until they fledge 20–26 days later.
Both adults feed the chicks in the nest and continue after they fledge until they become independent in about 8–14 days.
Normally only one brood is raised each year.
When nest boxes are used, the clutch size and number of fledglings are greater in larger boxes.
For reasons that are unclear, there is no link between cavity size and nesting outcomes for natural holes.

The sedentary nature of this species means that juveniles can only acquire a territory by finding a vacant area or replacing a dead adult.
In Europe, young birds almost always move to unoccupied habitat, but in the larger territories of Siberia most live within the breeding range of an adult pair.

The adult annual survival rate across most of the range is around 51%, and a small Belgian study found a 25% local survival rate for juveniles.
The typical lifespan is two years and the maximum known age for a wild bird is 12 years 11 months in the UK.
There is also a Swiss longevity record of 10 years 6 months.
Nuthatches are monogamous, and a pair occupies a breeding territory in which it spends the winter as well. Territory sizes range from 2–10 ha (5–25 acres) in Europe to an average of 30.2 ha (75 acres) in the sub-optimal conifer forests of Siberia. The male sings to defend his territory and attract a mate. Both sexes have a courtship display with a floating, quivering flight, and the male will also make circular flights with a spread tail and raised head. He will also feed the female while courting her. Despite the lifelong pairing, genetic research in Germany showed that at least 10% of the young in the study area were fathered by another male, usually from an adjacent territory.
The nest is in a tree cavity, usually an old woodpecker hole, but sometimes of natural origin. Occasionally the female will enlarge an existing hole in rotten wood. The nest site is typically 2–20 m (7–66 ft) above the ground and has a deep base of pine bark or chips of other wood, rarely supplemented with dry plant material. If the entrance to the hole is too large, it is plastered with mud, clay and sometimes dung to make it smaller. A small entrance and large interior, together with the use of a deep layer of wood chips in which to bury the eggs and small young when the adults leave the nest, may be adaptations to reduce the chance of predation. Nests with small entrance holes are most successful. Locally, a small entrance may make it less likely that the nest will be taken over by common starlings. The female undertakes most of the work, and often plasters the inside of the cavity too, taking up to four weeks to complete the construction. A nest is often re-used in subsequent years.
The clutch is usually 6–9 red-speckled white eggs, although up to 13 eggs are sometimes laid. They average 19.5 mm × 14.4 mm (0.77 in × 0.57 in) and weigh 2.3 g (0.081 oz) of which 6% is shell. The female incubates the eggs for 13–18 days to hatching, and broods the altricial downy chicks until they fledge 20–26 days later. Both adults feed the chicks in the nest and continue after they fledge until they become independent in about 8–14 days. Normally only one brood is raised each year. When nest boxes are used, the clutch size and number of fledglings are greater in larger boxes. For reasons that are unclear, there is no link between cavity size and nesting outcomes for natural holes.
The sedentary nature of this species means that juveniles can only acquire a territory by finding a vacant area or replacing a dead adult. In Europe, young birds almost always move to unoccupied habitat, but in the larger territories of Siberia most live within the breeding range of an adult pair.
The adult annual survival rate across most of the range is around 51%, and a small Belgian study found a 25% local survival rate for juveniles. The typical lifespan is two years and the maximum known age for a wild bird is 12 years 11 months in the UK. There is also a Swiss longevity record of 10 years 6 months.
Eurasian nuthatch