The pileated woodpecker is the largest woodpecker in North America and makes quite sizable nest cavities in trees. The holes they excavate are large enough to attract other species looking for a ready-made home, like ducks, owls, bats, and even raccoons. But just how big are the nest holes made by these charismatic carpenter birds? Let’s take a closer look at the details.
Pileated Woodpecker Facts
The pileated woodpecker (Dryocopus pileatus) is a crow-sized bird, 15-19 inches long with a wingspan of 26-30 inches. They have a distinctive bright red crest on the head and black and white plumage on the body. These woodpeckers are found across eastern North America, as well as parts of the Pacific Northwest and Canada.
Some key facts about pileated woodpeckers:
- They use their powerful chisel-like bill to hammer away at dead trees and excavate large rectangular holes for roosting and nesting.
- Their diet consists mainly of carpenter ants and wood-boring beetle larvae.
- Pileated woodpeckers are non-migratory and mate for life, using the same territory year-round.
- They lay 3-5 eggs in the nest cavity and both parents help care for the young.
- These woodpeckers play an important ecological role by creating habitat for other species.
Now let’s look at the specifics of their awe-inspiring nest holes.
Nest Hole Dimensions
Entrance Hole Size
The entrance hole to a pileated woodpecker nest is quite large, generally ranging between 2.5-6 inches wide and 2.5-4 inches tall. This large oval-shaped opening allows the adult birds to easily enter and leave the cavity.
While excavating, the male and female take turns chiseling away at the wood, each working on opposite sides of the hole. They can create this sizable entrance in just over a week’s time.
Cavity Depth
Once inside the entrance hole, the nest cavity itself extends further into the trunk of the tree. Pileated woodpecker nest holes are remarkably deep, averaging around 15-25 inches deep. However, they have been documented creating cavities up to 40 inches deep in some cases!
This great depth provides insulation and protection for the nestlings once eggs are laid. It also allows room for the young birds to move around as they grow.
Interior Dimensions
The interior space of the nest is also quite roomy to accommodate the large birds. Average dimensions are around 12 inches wide by 8 inches tall.
However, pileated woodpeckers may adjust the size based on the diameter of the tree. Narrower trees mean the cavities are more vertically elongated. Wider trunks allow for more horizontal space.
Preferred Nest Trees
Pileated woodpeckers typically excavate their nest cavities in mature live trees and snags (dead trees). Favorite species include aspen, birch, maple, alder, pine, spruce, cottonwood and willow.
Occasionally they may also nest in utility poles if natural options are limited. The wood needs to be not too soft, but not overly hard either, to enable excavation. Decaying internal heartwood is best.
Height Above Ground
These woodpeckers tend to nest fairly high up, usually 20-60 feet above ground. This helps protect the nestlings from potential predators.
The height also correlates with cavity depth. Higher sites tend to have deeper holes compared to lower ones, likely for added insulation and security.
Number of Cavities
A pileated woodpecker pair may excavate multiple different nest holes within their territory during a breeding season. One study found an average of about 3-4 available unused holes per breeding pair.
Not all cavities turn into active nests. The birds roost in the unused holes, plus having backups provides options if predators or competitors take over one site.
Nesting Behavior
Excavation Timeline
Pileated woodpeckers start excavating potential nesting cavities up to a few months before eggs are laid. This ensures suitable options are available when it’s time to breed.
The male does most of the excavating work, up to 90% of it. The process is energetically expensive, often taking 2-6 weeks to complete a single hole.
Nest Reuse
A pileated woodpecker nest hole may be reused for multiple years, even decades in some cases. The birds often return to prior nest sites if they remain suitable, doing minimal additional excavating to clean it out.
This saves energy compared to making an entirely new cavity each time. Some researchers estimate a single nest hole may be reused up to 20 times over many generations.
Roosting Use
In addition to nesting, pileated woodpeckers also roost in their cavities year-round. The entire family group may pile into one large hole for the night.
The insulated depths provide protection from weather and predators. Multiple birds can wedge in together safely, with documented reports of up to 17 pileated woodpeckers in a single cavity!
Impacts on Other Species
Secondary Cavity Nesters
Many other bird and animal species cannot excavate cavities themselves but readily use abandoned pileated woodpecker holes. These are called secondary cavity nesters.
Species that may reuse old pileated holes include:
- Wood ducks
- Barrow’s goldeneyes
- Common goldeneyes
- Hooded mergansers
- Common mergansers
- Buffleheads
- Northern flickers
- American kestrels
- Eastern screech owls
- Boreal owls
- Northern saw-whet owls
- Bats (various species)
- Southern flying squirrels
- Raccoons
- American marten
- Fisher
The large size and prime placement of pileated holes makes them highly attractive real estate!
Cavity Competition
In some cases, other species may directly compete with pileated woodpeckers for the same holes. Known competitors include:
- Northern flickers
- European starlings
- Red-breasted nuthatches
- Flying squirrels
- Bees and wasps
Strong excavators like flickers pose the biggest problem. They not only take over pileated holes, but can destroy a nesting attempt by enlarging the entrance. Starlings may swarm a cavity in huge numbers.
Ecosystem Engineers
Pileated woodpeckers provide a vital service to many plants and animals by creating these large nesting and roosting cavities. Their carpentry benefits the broader ecosystem.
Scientists call them ecosystem engineers because they physically construct a resource used by many other species. Protecting pileated woodpecker populations helps ensure cavity availability.
Key Facts Summary
Here are the key facts to remember about the incredible nest holes created by pileated woodpeckers:
- Entrance holes average 2.5-6 inches wide and 2.5-4 inches tall.
- Interior cavity depth ranges from 15-25 inches on average.
- Cavity interior dimensions typically around 12 inches wide by 8 inches tall.
- Mature aspens, pines and other live trees are preferred nest sites.
- Nest height is usually 20-60 feet above the ground.
- A mated pair may excavate 3-4 unused holes per breeding season.
- Cavities are often reused for many years.
- The full family roosts together in cavities at night.
- Abandoned holes are readily used by many secondary cavity nesting birds and mammals.
The pileated woodpecker’s nest is a masterpiece of avian engineering and industriousness. The large cavity provides safe haven for adults, young, and many other species. Their carpentry skills exemplify the incredible adaptations of North American woodpeckers.
Conclusion
In summary, pileated woodpecker nest cavities are quite sizable, with entrance holes 2.5-6 inches wide leading to deep interior chambers averaging 15-25 inches deep. These large holes are excavated into mature trees 20-60 feet high and reused for many years. Abandoned pileated nests are hot commodities, providing crucial habitat for numerous secondary cavity nesting birds and mammals. The pileated woodpecker truly is the supreme excavator and ecosystem engineer of North American forests. Their awe-inspiring nest holes reveal the skills of a consummate carpenter.
