Woodpeckers are remarkable cavity nesters, excavating homes in trees and other substrates. This article explores their nesting habits, from cavity construction and location preferences to adaptations in various environments. It also covers the ecological significance of woodpecker cavities and the strategies these birds employ to create and defend their specialized nesting cavities .

All woodpeckers are cavity Nesters
All woodpeckers are cavity nesters, meaning they create their own cavities in trees or other substrates for nesting, raising their young, and roosting. Unlike some cavity-nesting birds that rely on finding existing holes, woodpeckers are known for excavating their own cavities using their powerful bills.
Cavity Location: Woodpeckers typically choose cavities located in tree trunks or branches, preferring areas with a mix of rotten wood for easier excavation and sound wood for structural integrity.
Tree Species Preference: Most species that nest in living trees select those with softer wood, such as aspens, to facilitate excavation. Red-cockaded woodpeckers preferentially excavate their nesting cavities in live pine trees infected with red heart fungus. This fungus softens the heartwood of the tree, making it easier for the woodpeckers to create their cavities while maintaining a solid outer structure.
Climate Considerations: Nest orientation varies based on the climate. In colder regions, cavities often face south or east to maximize sun exposure, while in warmer climates, they face north to prevent overheating.
Desert Adaptations: In desert environments where trees are scarce, woodpeckers have adapted to nesting in tree-sized cacti like saguaros.

Saguaro Boots: The protective fluid secreted by the cactus hardens into a shell around the cavity, sometimes outlasting the cactus itself. These detached nest cavities are known as “saguaro boots” due to their shape.
Alternative Nesting Sites: A few woodpecker species have adapted to nesting in substrates other than trees, such as termite mounds or earthen banks. They may also utilize human-made structures like utility poles or buildings.
Cavity Construction parts and characteristics
- Entrance Hole: The cavity typically begins with a round entrance hole just large enough for the adult bird to enter.
- Vertical Chamber: The entrance leads to a larger vertical chamber with a rounded bottom where the eggs are laid and the young are raised.
- Nest inside: Woodpeckers do not build a conventional nest nor bring any type of material to the cavity. They rely primarily on wood chips created during excavation to cushion the eggs.
Cavity shape and size

Generally woodpeckers build a round entrance. The only known variation is the entrance hole of cavities excavated by the Pileated Woodpecker, which is oblong.
Coarser Cutting Patterns in Larger Species: One detail that can be difficult to notice is that cavities excavated by larger woodpeckers, with their larger bills, exhibit coarser cutting patterns around the rim of the entrance hole.
Entrance Size as an Identifier: The most distinctive variation among species is the size/diameter of the entrance hole. The entrance hole is typically just large enough to accommodate the adult bird and gives clues for identifying which woodpecker species created such cavities.
The table below shows 17 woodpecker species and their corresponding cavity entrance sizes. The table offers a useful guide for identifying woodpecker species based on their cavity entrance sizes, ranging from the smaller Downy Woodpecker with a 1-1.5 inch entrance to larger species like the Pileated Woodpecker with a 4.7 inch entrance. This information can be valuable for birdwatchers and researchers in the field.
Species | Cavity Entrance Size (inches) |
Downy Woodpecker | 1.0 |
Hairy Woodpecker | 1.5 |
Ladder-backed Woodpecker | 1.5 |
Yellow-bellied Sapsucker | 1.5 |
Williamson’s Sapsucker | 1.5 |
Black-backed Woodpecker | 1.5 |
Three-toed Woodpecker | 1.5 |
White-headed Woodpecker | 1.5 |
Red-bellied Woodpecker | 2.0 |
Acorn Woodpecker | 2.0 |
Gila Woodpecker | 2.0 |
Arizona Woodpecker | 2 |
Red-cockaded Woodpecker | 2.5 |
Red-headed Woodpecker | 2.5 |
Lewis’s Woodpecker | 2.5 |
Northern Flicker | 3.0 |
Pileated Woodpecker | 4.7 |
Do woodpeckers reuse their nesting cavities?
Most woodpeckers excavate a new cavity each breeding season and generally prefer a fresh cavity. However, some pairs reuse the same cavity for subsequent nesting, particularly when they have a successful breeding attempt at such cavity.
Reasons for New Cavities
Preference for fresh cavities may be driven by several factors:
- Deterioration: Older cavities may have deteriorated over time, making them less suitable for nesting.
- Parasites: Existing cavities may harbor parasites that could harm the woodpecker chicks.
- Predation Risk: Predators may remember the locations of previous cavities, increasing the risk of predation for woodpeckers that reuse them.
Ecological Significance of woodpecker cavities
Abandoned woodpecker cavities play a crucial role in forest ecosystems, providing nesting and roosting sites for other cavity-nesting birds, mammals, and invertebrates. Ecological benefits include:

1. Providing habitat: Abandoned woodpecker cavities offer essential nesting and roosting sites for over 35 secondary cavity-nesting species, including birds, mammals, reptiles, amphibians, and insects.
2. Supporting biodiversity: These cavities are vital for maintaining populations of secondary cavity nesters, which account for about one-third of forest vertebrate species in some regions.
3. Enhancing nesting success: Secondary cavity nesters have higher probabilities of success when using abandoned woodpecker cavities compared to decay-formed cavities. Woodpecker-created cavities have smaller entrance holes and deeper depths compared to naturally formed cavities.
4. Ecosystem services: Species using woodpecker cavities contribute to pest control, serve as prey for predators, support ecotourism, and maintain biodiversity.
5. Limiting factor: Suitable cavity availability can be a limiting factor for secondary cavity-nesting bird populations, making woodpecker cavities essential for their survival.
Competition for woodpecker cavities
Woodpecker cavities are highly sought-after by other cavity-nesting birds and animals, creating competition for these valuable resources. Woodpeckers may aggressively defend their cavities from rivals, using a combination of vocalizations, displays, and even physical attacks.
Some species employ strategies to minimize the risk of being usurped, such as placing their nests on the underside of small branches, making them less accessible to larger birds.
The Red-cockaded Woodpecker creates distinctive “sap wells” around the tree above and below the cavity entrance, thought to deter predators and competitors.
How long does it take for a woodpecker to excavate a new cavity?
The time required for woodpeckers to excavate a cavity varies significantly depending on the species and tree type. While species of woodpeckers in North America take from 1 to 6 weeks, the Red-cockaded Woodpecker constitutes an outlier.
This endangered woodpecker excavates cavities in live pine trees. It takes them over 13 years in longleaf pine and over 10 years in loblolly pine of intermittent excavation to complete a nesting cavity. Red-cockaded Woodpecker reuse the same cavity after completion.
As shown on the table below, smaller woodpeckers excavate new cavities in shorter periods of time.
Species | Time to Excavate a new Cavity |
Downy Woodpecker | 7 to 20 days |
Red-bellied Woodpecker | 7 to 10 days |
Red-headed Woodpecker | 12–17 days |
Northern Flicker | 8-20 days |
Pileated Woodpecker | 3–6 weeks |
Breeding Activities Performed by Male and Female Woodpeckers
Excavation of the cavity: In most woodpecker species of North America, both male and female help excavate the nesting cavity, but the male does most of the work. The male starts the excavation and works through to a point where the cavity is nearly finished. Then the female begins to work on the final touches in the chamber.

Incubation of the eggs: After the female lays the eggs, she does most of the incubation. In most species, the male helps with incubation when the female leaves the nest to feed and preen.
Raising the Young: The female stays with the newly hatched birds while the male brings food for both the female and the chicks. After a few days, both birds work equally to bring food and feed the young birds in the nest.
Conclusions:
Woodpeckers exemplify remarkable adaptability through their nesting habits and cavity construction. Their ability to excavate new cavities for breeding and roosting not only ensures their survival but also provides essential habitats for various other species, highlighting their ecological significance. The diverse nesting strategies employed by different woodpecker species reflect their evolutionary success across various environments. Protecting woodpecker habitats is crucial for maintaining biodiversity and forest health, as these skilled birds play a vital role in shaping ecosystems.
See also: Regional Guides to the Woodpeckers of North America
Additional resources:
- Woodpecker Feet and Toes
- The Woodpecker Tail
- The Woodpecker Tongue
- Understanding Woodpecker Drumming Behavior
- Woodpecker Migration
- Woodpecker Damage: Methods to Protect your Home
References and Sources:
- Allaboutbirds.org)
- Gill, Frank B., 1994. Ornithology – 2nd Edition, W. H. Freeman and Company.
- The Sibley Guide to Bird Life and Behavior, 2001. Chris Elphick, John Dunning, and David Sibley (eds). Alfred A. Knopf, New York.