Red-breasted nuthatches are monogamous. They form breeding pairs beginning in winter or spring, and stay together for a year or more. Each pair defends a territory through the breeding season, and possibly through the year if the cone crop is good. In order to attract a female, males perform courtship displays that include raising their head and tail, drooping the wings, and fluffing the back feathers. A male sways from side to side and sings with his back turned toward the female. During courtship, males sing up to 50 times per minute from the tops of trees and potential nest trees. They also bring food to the female during courtship.
Mating System: monogamous
Red-breasted nuthatches begin breeding in their first year. Both adults take part in nest building. They usually dig a cavity in a tree stump or a branch of a dead tree, or occupy a vacant woodpecker hole. They use smeared resin to protect the inside of the nest, allowing just enough room for their body widths. This prevents insects, small mammals, and other birds from entering the nest cavity. Inside the cavity is a cup nest built with grasses, roots, mosses, shredded bark, and plant fibers.
Breeding occurs from mid-April through early August, with peak activity from May through July. Red-breasted nuthatches raise one brood per year. The female lays 5 to 8 (usually 6) pinkish-white eggs that are speckled with a reddish brown color. One egg is laid each day. The female incubates the eggs, which hatch after 12 to 13 days. During incubation, the male provides food to the female, allowing her to spend more time on the nest. After the eggs are hatched, the altricial nestlings are brooded for the first few days by the female. The male brings food to both the female and young. The young leave the nest 18 to 21 days after hatching. They become fully independent about 2 weeks after fledging.
Breeding interval: Red-breasted nuthatches breed once yearly.
Breeding season: Breeding occurs from mid-April through early August, with peak activity from May through July.
Range eggs per season: 5 to 8.
Average eggs per season: 6.
Range time to hatching: 12 to 13 days.
Range fledging age: 18 to 21 days.
Average time to independence: 14 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)
Average eggs per season: 5.
Because nuthatch chicks are hidden in nest cavities, little is known about the development. The newly hatched young are altricial, which means they are immobile, have closed eyes, and must be cared for by the adult. The female broods the chicks for the first week after hatching. During this time, the male brings food to the nest for the female and chicks. During the nestling and fledgling periods, both adults feed the chicks. They also remove the fecal sacs of the chicks from the nest. The chicks typically leave the nest 18 to 21 days after hatching, but may remain partially dependent on their parents for food for another two weeks.
Parental Investment: altricial ; pre-fertilization (Provisioning); pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)