Nuthatches are small songbirds found throughout North America. They are known for their ability to crawl up and down tree trunks and branches and nest inside cavities in trees. Nuthatches are non-migratory birds and remain in their breeding territories year-round. The timing of their nesting and breeding activities varies across their range, primarily influenced by latitude and altitude.
Spring Nesting in the South
In the southern parts of their range, such as the southeastern United States, nuthatches begin nesting activities in early spring. The exact timing can vary by species:
- White-breasted Nuthatches start nesting as early as late February or March in Florida.
- Brown-headed Nuthatches commence nesting in March or April in the deep south.
- Red-breasted Nuthatches initiate nesting in April or May in the south.
Nuthatches are cavity nesters and don’t build an enclosed nest like many other birds. However, they still engage in nesting behaviors like claiming a territory, excavating a cavity, and lining the cavity with soft materials. Excavation often begins up to two months before eggs are laid.
Spring Nesting in the North
Farther north, nuthatches breed later in spring due to colder temperatures and later emergence of food sources like insects. For example:
- White-breasted nuthatches in northern states like Minnesota and Maine begin excavating nesting cavities in April and may not lay eggs until late April or May.
- Red-breasted nuthatches in Canada postpone nesting until May or even early June.
Elevation affects nest timing as well, with birds at higher elevations nesting later. In mountainous areas, nuthatches may not start nesting until June or July.
Second Nesting Attempts
Nuthatches frequently make a second nesting attempt if their first is unsuccessful. This “double brooding” is more common in southern populations with a longer breeding season. Second nesting efforts typically commence 4-8 weeks after the first. For example, white-breasted nuthatches unsuccessful in March may re-nest as late as May or June further north. This maximizes their chances of successful reproduction that year before conditions deteriorate in winter.
Clutch Size
When nuthatches breed, females lay relatively large clutches of 5-9 eggs (average 6-7). Larger clutches sizes are more common among southern populations compared to northern birds. For example, white-breasted nuthatches may lay 9 eggs in Georgia but only 5 in Minnesota. The table below shows some average clutch sizes by species and region:
Species | Region | Average Clutch Size |
---|---|---|
White-breasted Nuthatch | Southeast U.S. | 8-9 eggs |
White-breasted Nuthatch | Northeast U.S. | 5-6 eggs |
Red-breasted Nuthatch | Pacific Northwest | 5-7 eggs |
Brown-headed Nuthatch | Deep South | 6-8 eggs |
Incubation
Only female nuthatches incubate their eggs. The incubation period lasts about 12-14 days. Males help feed the incubating females. Nuthatch hatchlings are altricial, meaning they are helpless, naked, and blind at hatching. Both parents feed and care for the young, which fledge (leave the nest) after about 18-25 days.
Fall and Winter Nesting
While less common, some nuthatch populations continue breeding activities into fall and winter. Red-breasted nuthatches are most likely to nest late in the year, especially those living in mild coastal climates like the Pacific Northwest. Food availability seems to be the main driver of late nesting. When conifer seed crops are abundant from September through November, red-breasted nuthatches may take advantage by raising an additional brood.
Other nuthatch species nesting late in the year usually do so because earlier nests failed. For example, a southern white-breasted nuthatch pair that lost eggs in June may re-nest in August. However, nesting success tends to be lower outside of spring and early summer when weather conditions are less stable.
Geographic Variation
The timing of nesting in nuthatches varies across different parts of the country based primarily on local climate and weather conditions:
- Earliest nesting – February to April in southern states like Florida, Texas, and the Southwest.
- Typical nesting – March to June across the central U.S.
- Later nesting – April to July in northern states and at higher elevations.
- Potential for fall nesting – Along the Pacific Coast.
This geographic variation allows nuthatch populations to adapt their breeding chronology to local environments across their broad distribution in North America.
Conclusion
Nuthatches exhibit flexibility in the timing of their breeding activities to maximize reproductive success. While they nest primarily in spring, the specific months vary across their range. Southern populations nest earlier, starting as early as February. More northern birds delay nesting until April or May. High elevation populations nest latest, sometimes not until June or July. Red-breasted nuthatches in mild climates occasionally breed again in fall or winter. Understanding the regional and seasonal differences in nuthatch breeding biology provides insights into how bird populations adapt their annual cycles across diverse habitats.