Nuthatches are small songbirds found throughout North America, Europe, and Asia. They get their name from their tendency to hatch or “hack” open seeds and nuts using their long, chisel-like bills. Nuthatches are cavity nesters, meaning they build their nests and lay eggs inside holes or crevices in trees. But how long do nuthatches actually sit on their eggs before they hatch? Let’s take a closer look at nuthatch reproduction and incubation behavior.
Nuthatch Breeding Season
Nuthatches breed early in the spring, with breeding seasons varying slightly across different nuthatch species and geographic ranges. In general, the breeding season for nuthatches in North America runs from late March through July.
Red-breasted nuthatches are some of the earliest nesters, beginning to breed in late March or early April. White-breasted nuthatches start nesting in April or May. Pygmy nuthatches in the southwestern U.S. breed between mid-March and mid-June.
The exact timing depends on latitude and elevation. Nuthatches that live further north or at higher elevations tend to nest later in the spring as they wait for winter weather to subside and food sources to become available.
Nesting and Egg Laying
Once they form monogamous breeding pairs, nuthatch couples work together to build a nest. The nest is constructed out of bark flakes, twigs, grass, moss, fur, and feathers. It takes 10-14 days to complete the nest.
Female nuthatches then lay a clutch of 5-9 eggs. The eggs are tiny, measuring just 0.6 inches long. They are smooth, glossy, and pale bluish-white with reddish-brown speckles.
The female lays one egg per day until the clutch is complete. She does not start incubating the eggs right away. Instead, she waits until the last egg is laid before beginning consistent incubation. This ensures that all the eggs hatch around the same time.
Incubation
So how long does a nuthatch sit on its eggs? The incubation period for nuthatches is about 12-14 days. During this time, the female does the majority of incubating while the male brings food to her. She develops a brood patch – a bare patch of skin on her belly used to transfer warmth to the eggs.
The female nuthatch sits tightly on the eggs nearly continuously, leaving the nest for only brief 10-15 minute breaks each day to eat, drink, preen, or defecate. The male may temporarily take over incubation duties during the female’s short breaks. But overall, incubating females spend about 90% of their time on the nest during the incubation period.
Nuthatch eggs require consistent warmth and humidity to develop properly. If the eggs are left uncovered for too long, the embryos inside could die. So females are dedicated to incubating for about 85% of each 24 hour period. They rarely leave the nest overnight.
Hatching
After 12-14 days of determined incubation, the nuthatch eggs begin to hatch. Hatching may take up to 2 days as each egg pipps open at slightly different times.
The hatchlings emerge weak, blind, and naked. But they develop quickly thanks to devoted care from both parents who feed the chicks regurgitated insects. The chicks fledge from the nest at 18-28 days old.
Incubation Duties Vary Across Nuthatch Species
While female nuthatches perform the majority of incubating duties, the exact split of responsibilities varies somewhat across the different nuthatch species.
For example, in white-breasted nuthatches, females spend about 91% of daylight hours incubating. Males incubate for the remaining 9%. Males also take over incubating at night, allowing females to roost away from the nest.
In red-breasted nuthatches, females incubate slightly less. They average about 83% of daytime incubating. Males incubate around 17% of daylight hours.
Pygmy nuthatch females perform the highest share of incubating, sitting on the eggs for approximately 94% of daylight hours. Their smaller male counterparts incubate just 6% of the time.
But across all species, the female’s commitment to egg-warming is impressively high during the 12-14 day incubation period. This dutiful incubation by the female, with some assistance from her mate, is key to successfully hatching a healthy clutch.
How Does Temperature Impact Incubation?
Outdoor temperature impacts how much time nuthatch parents spend incubating. When temperatures drop, females must sit on the eggs more consistently to maintain the warmth needed for embryonic development.
One study of pygmy nuthatches in Nevada found that incubating females left the nest significantly less often on colder days compared to warmer days. On cold days around 50°F (10°C), females took about 0.5 recesses per hour. But on hot days near 86°F (30°C), females took approximately 2.5 recesses per hour to get food and water.
Higher temperatures allow females to take longer and more frequent breaks. But colder weather means less opportunity to leave the eggs exposed. The female nuthatch’s body heat is vital for keeping the clutch at the proper temperature when outdoor conditions get chilly.
Temperature Regulation in the Nest
Nuthatch nests are often built in tree cavities or nest boxes that provide insulation. But fluctuations in outdoor temperatures can still impact the conditions inside the nest.
When incubating females sense the nest temperature dropping, they shudder to generate heat. They may also hunker down tighter over the eggs, exposing less of their surface area to the air.
If the nest overheats, nuthatches have some tricks to cool it down. Adults may flick water onto the eggs or fan the eggs with their wings. A hot nest can threaten embryo survival just like a cold nest, so nuthatches work to maintain a temperature between 86-100°F (30-38°C).
Conclusion
Nuthatches demonstrate remarkable dedication to incubating their eggs. Despite their tiny size, nuthatches are capable of sitting consistently for up to 13 days to maintain the proper conditions for their developing chicks.
Female nuthatches perform the vast majority of incubation duties. But their male mates still play an important supporting role by bringing food and occasionally taking over egg-sitting responsibilities. This joint effort by the breeding pair ensures their eggs stay warm and humidified until the day the chicks are ready to hatch.
Frequently Asked Questions
How many eggs do nuthatches lay?
Nuthatches typically lay between 5-9 eggs per clutch. The exact number varies slightly by species.
Do both nuthatch parents incubate the eggs?
Yes, both the female and male nuthatch help incubate the eggs. However, the female takes on the majority of incubating duties, sitting on the nest about 90% of the time during daylight hours. The male will incubate the remaining 10% of the time and takes over incubating at night in some species.
Do nuthatches reuse the same nest?
It depends. Some nuthatch pairs may reuse the same cavity or nest box for consecutive broods in the same breeding season. But they often build a completely new nest each year rather than reusing the old nest.
How do baby nuthatches leave the nest?
Once the nuthatch chicks are 18-28 days old, they are ready to fledge, or take their first flight from the nest. The parents coax the chicks out of the cavity by calling to them and showing them food. The fledglings follow their parents to learn how to forage.
What temperature is best for incubating nuthatch eggs?
Nuthatch eggs do best when incubated at temperatures between 86-100°F (30-38°C). The parents work to maintain conditions in this range inside the nest. If temperatures drop too low, the eggs could die. If they get too hot, embryo development could be compromised.
Comparison of Nuthatch Species
| Species | Incubation Period | Clutch Size | % Female Incubates |
|---|---|---|---|
| White-breasted nuthatch | 12-14 days | 5-9 eggs | 91% |
| Red-breasted nuthatch | 13-14 days | 5-9 eggs | 83% |
| Pygmy nuthatch | 13 days | 6-8 eggs | 94% |
Key Facts About Nuthatch Incubation
- Incubation period lasts 12-14 days
- Female sits on the nest about 90% of daylight hours
- Male incubates the remaining 10% of the time
- Female rarely leaves nest overnight
- Outdoor temperature impacts recess frequency
- Parents use behaviors like wing-fanning to regulate nest temperature
- Ideal incubation temperature is 86-100°F (30-38°C)
Nuthatches demonstrate impressive dedication to incubating their eggs. The female’s commitment to consistent egg-warming, with some help from her mate, allows the clutch to hatch after 12-14 days of attentive care. Proper incubation is key to reproductive success for these cavity-nesting songbirds.
More Facts About Nuthatch Nesting Behavior
Nuthatches exhibit fascinating nesting behaviors beyond just incubation:
- Nuthatch pairs often reuse the same nest cavity or nest box for multiple broods in a single breeding season.
- Females perform most of the 9-14 day nest building process, but males help gather materials.
- Nesting materials include bark, twigs, grass, moss, fur, and feathers.
- Nuthatch nests are often lined with shredded bark to help regulate humidity.
- Females lay one egg per day until the clutch of 5-9 eggs is complete.
- Parents may smear tree resin around the nest entrance to deter predators and competitors.
- Young nuthatches hatch blind and naked but develop quickly.
- Chicks fledge from the nest at 18-28 days old.
From nest construction through egg-laying, incubating, and rearing hatchlings, nuthatches engage in intricate breeding behaviors centered around their cavity nests. The adaptations that allow them to utilize tree holes for nesting contributes to their success as a cavity-nesting species.
Incubation in Other Bird Species
While nuthatch incubation habits are fascinating, they are certainly not unique among birds. Here is how the incubation period of nuthatches compares to that of other species:
Similar Incubation Periods
- Chickadees: 12-13 days
- Bushtits: 12-18 days
- Titmouse: 13-14 days
- Wrens: 12-16 days
Many small songbirds have incubation periods lasting about two weeks, just like nuthatches. Chickadees and titmice, also cavity nesters, have especially comparable incubation times.
Shorter Incubation Periods
- Mourning doves: 14 days
- Bluebirds: 13 days
- Finches: 12-14 days
- Warblers: 11-12 days
Smaller songbirds like warblers and finches tend to have slightly shorter incubation periods than nuthatches. Their smaller clutches may require a little less time to develop.
Longer Incubation Periods
- Woodpeckers: 14-18 days
- Jays: 16-18 days
- Golden eagles: 35-45 days
- Mallards: 28 days
Larger birds including woodpeckers, jays, waterfowl, and raptors need more time for their eggs to hatch. Their longer incubation periods reflect their bigger body sizes and clutch sizes.
So while nuthatches aren’t unique in incubating for about two weeks, this behavior is still fascinating to observe in context of the incredible diversity of avian breeding strategies. Nuthatches demonstrate a remarkable commitment to attentive incubation, a key part of their cavity nesting life history.
Conclusion
Nuthatches depend on dutiful incubation by the breeding pair, especially the female, to successfully hatch their eggs. Attentive egg-sitting for 12-14 days provides the clutch with consistent warmth and humidity. This allows the helpless hatchlings to fully develop before emerging blind and featherless into the nest.
Understanding details like incubation duration sheds light on the breeding ecology of these widespread cavity nesters. Nuthatches exemplify the intricate reproductive behaviors used by birds to promote fitness and facilitate the next generation. Their dedication as parents starts long before the chicks ever emerge. Careful incubation by nuthatches plays a vital role in continuing the success of these charismatic songbirds.
