Monday, January 20, 2020

Where do Red-breasted Nuthatches like to nest?

Red-breasted Nuthatches live in conifer woods primarily in the north and West. In winter some of the northernmost birds migrate south, irregularly in large numbers. Then they may show up out of place or at your feeder. If the habitat is right, they may even stay around to nest.

Have you seen Red-breasted Nuthatches at your backyard feeder and wondered where they nest? Do you wonder if you could convince them to stay for the summer if you offered some kind of birdhouse or nest box?

Red-breasted Nuthatches may rarely use a nest box that you provide. Usually, however, they prefer to excavate their own nest in a dead branch of a tree. They like to dig out a new nest cavity every year.

This page is a supplement to my overview of the Red-breasted Nuthatch. The overview page leads to other more in-depth pages on identification, food and diet, range and habitat, and back to this page on nesting and reproduction.

Photo of a fledgling Red-breasted Nuthatch on lichen-covered branch
A young fledgling Red-breasted Nuthatch recently out of the nest
Photo by Greg Gillson

Nesting habits and reproduction of Red-breasted Nuthatches


The nesting season for Red-breasted Nuthatches runs from May to July throughout most of their large range. But since some birds nest in Alaska, some in Arizona, some in the lowlands, and some in the mountains, the nesting season can often be extended beyond this. Even so, nesting behaviors are pretty much confined to the time period from late April into early August.

In spring the nesting habits include courtship behaviors to strengthen pair ponds. Then they begin excavating their nest. When the nest is complete they lay and incubate the eggs. Soon the eggs hatch and the busy parents are flying back and forth to the nest to feed their hungry young. It isn't long before the young leave the nest and soon the nesting season is over. Each of these steps are discussed below.

All nuthatches are monogamous and mate for life. The pair defends their territories from other nuthatches. They usually only produce one brood of young per year.

Courtship and mating


Courtship and pair interaction starts the breeding season. Most nuthatches only make nasal call notes and run these together, either more loudly or more rapidly, to form a song. However, the male Red-breasted Nuthatch also includes a soft musical song during courtship.

The male courts the female by singing and swaying motions, often with their back turned toward the females and their crown feathers raised. Pairs may also slowly fly together with fluttery wingbeats and glides.

Because the pair may remain together all year round, it is hard to discern exactly when courtship begins in the spring.



Nest building


Females start inspecting dead branches or taller rotten tree stumps for a suitable place to start excavating the nest. Usually the female does most of the work building the nest.

Red-breasted Nuthatches really like mature conifer forests because these contain larger dead trees and branches. On the other hand, they may seek openings in the trees where aspen trees grow along streams. Aspens have softer wood making it easier to excavate nest cavities.

Nest cavities are built anywhere from 5 to 40 feet high. The average height of the nests are about 15 feet above the ground.

The male sometimes helps the female excavate the nest. Frequently, though, the female does the work. Her mate may bring her food, though, while she works.

Red-breasted Nuthatches become very territorial and aggressive during the nest building time. They chase away any other Red-breasted Nuthatches from their territory. But they also chase away other hole-nesting birds that might compete with them for a good place to build a nest. They chase away White-breasted Nuthatches, House Wrens, and Downy Woodpeckers.

Red-breasted Nuthatches take quite a while to build their nests. One source says they take about 18 days to dig their nest. Another source says it takes 1 to 8 weeks to complete excavating their nests!

As an example of the time of year that Red-breasted Nuthatches excavate their nest I use the Breeding Bird Atlas results from Oregon and San Diego, California. Volunteers found these nuthatches building nests from April 18 to June 14 in Oregon. In San Diego County where these birds are rather rare in the mountains, volunteers looking for breeding evidence found a Red-breasted Nuthatch excavating a nest on May 23.

When the hole is completed the nuthatches line the bottom of the cavity with mosses, grass, strips of bark, feathers, and other plant material. They may even steal nesting material from the nests of other hole nesting birds such as chickadees!

An interesting behavior is that Red-breasted Nuthatches smear pine pitch around the entrance hole of their nest. They may use their bill to do this. Sometimes they may use a piece of bark to spread the conifer pitch around. Thus, if you find a small hole in a dead tree with pitch around the entrance in spring, it is likely an active Red-breasted Nuthatch nest.

The pitch around the nest hole may keep other predators and insects away. The nuthatches avoid the sticky pitch by flying straight into the nest hole, and not crawling into it from below.

Red-breasted Nuthatches prefer to dig new nest holes. But sometimes they may reuse a nest cavity from a previous year. They may also use old deserted nesting cavities of smaller woodpeckers.

You can encourage Red-breasted Nuthatches to nest in your backyard by planting conifers, especially pines. Don't cut down dead trees right away or eliminate dead branches completely. Keep them up as long as possible. Nuthatches may not nest in a dead tree until the bark has died and peeled off, and maybe the inside of the tree is softer with rot. Of course, if the tree presents a hazard, of if dead trees are not allowed by your city code, then you must cut them. But if you are able to have a "wild" edge to your yard, then allow dead trees and branches to persist for wildlife.

Nest boxes


If there are conifers around but not many dead trees or dead branches in which to dig their nests, then Red-breasted Nuthatches may rarely use artificial nest boxes, also called birdhouses.

If you want to build your own nest box, or look for one to purchase, the inside dimensions should be about 4 inches wide by 4 inches deep. The height should be about 9 inches high with an entry hole about 7 inches up from the bottom. Place about 1 inch of wood shavings on the floor of the nest box.

Hang your nest box 12-15 feed high in a tree or place on a tall pole. You may also place the nest box on the side of a building.

Most important, the entry hole size should be 1-1/4 inches in diameter. Any smaller and they can't get their rather large heads in the hole. Any bigger and the nest hole may be taken over by larger birds such as House Sparrows and bluebirds.

The entry hole size of 1-1/4 inches will also allow other small cavity-nesting birds to use the nest box. Other species that like that size entry hold include some Bewick's and House wrens, Mountain, Black-capped, and Chestnut-backed chickadees, Oak and Tufted titmouses, and even Prothonotary Warblers and White-breasted Nuthatches.

Even House Sparrows might wriggle their way into this size birdhouse. But to help keep other birds from enlarging the nest box entry hole, use a copper birdhouse portal. This metal guard screws onto the wooden nest box with an entry hole just the right size for the bird you want. I include this ad from Amazon to show you what it is.



If you are interested in buying a nest box, rather than making your own, this Stokes Wren & Chickadee nest box (ad below) has good dimensions. Remember, don't buy a nest box with a dowel perch on the front--this allows too many undesirable birds to get access (European Starlings and House Sparrows, for example).



In cold weather nuthatches, wrens, and chickadees may roost in nest boxes in winter. Usually, though, they will only use them for nesting.

Eggs


Throughout their range, Red-breasted Nuthatches lay eggs from April to June. The Oregon Breeding Bird Atlas determined that most eggs were laid in that state in May and June, judging by the 24 days before young birds leave the nest and are much easier to see.

A pair of nuthatches lays 2 to 8 eggs, though 5 to 6 eggs is typical. Eggs are white or creamy and speckled with reddish-brown spots. Eggs are about 0.6 to 0.7 inches long.

The female does most of the incubation, probably especially at night. The male brings food to the female. The incubation period is about 12 to 13 days.

Young--nestlings and fledglings


Birds hatch from eggs; they are not "born," as such. Young birds in the nest are not "babies." They are nestlings. When young birds leave the nest they are called fledglings.

When the egg hatches the nestling is naked (without any feathers) and helpless. This is called altricial. Human babies are also altricial, requiring long parental care. Birds are much faster, though.

The mother bird continues to be the primary parent that incubates the nestlings and keeps them warm. Both the father and mother feed the nestlings.

The young are fed mostly, or entirely, insects and spiders.

Nests with young were found on the Oregon Breeding Bird Atlas from June 7 to July 12.

Nestlings grow down and then some juvenile feathers before even leaving the nest. This is amazing, as young leave the nest only 18-21 days after hatching! The juvenile body feathers do not last long (weeks) before the young birds molt again into the formative plumage and appear very similar to adults. The Red-breasted Nuthatch in the photo at the top of the article is undergoing preformative molt. (Source: Molt in North American Birds. 2010. Steve N. G. Howell.)

Records of the Oregon Breeding Bird Atlas found fledglings outside the nest cavity and accompanied by their parents from June 14 to July 21. In San Diego County, fledglings were noted from May 31 to July 23.

Back to the Overview page for Red-breasted Nuthatch.

2 comments:

  1. Love this info- thank you! I have a nuthach couple nesting in my owl box and they are so much fun to watch- I hope that I can see the fledglings soon

    ReplyDelete
    Replies
    1. I'm so glad you found this page useful!

      How exciting to have nuthatches nesting. They are fun indeed!

      Delete

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