The Red-breasted is the only North American nuthatch that regularly migrates. The birds migration is irruptive, meaning it moves southward in unusually large numbers during some winters. These eruptions may be tied to the extent of the cone crop in the birds breeding area. Like other nuthatches, this bird moves up and down the trunk and along thin branches of a tree with great agility and ease.
Blue-gray upperparts. Reddish underparts. Black crown and eyeline. White supercilium, face, and throat. Straight, grayish bill. Short tail. Sexes similar, but the female has duller coloring. 4.5 to 4.75 inches in length.
Coniferous forests, broadleaf forests. Widespread during migration and in winter.
5-6 white eggs with red-brown spots. The eggs have a 12 day incubation period. Fledging occurs in 14-21 days. The nest is a cup made from twigs and grass, lined with softer material and built in a tree cavity. The cavity entrance is often smeared with pitch, which presumably is used to discourage predators.