Pileated woodpeckers are the largest woodpecker species in North America. They are found throughout eastern forests, and are known for their loud, distinctive calls and the large rectangular holes they excavate in trees. Pileated woodpeckers play an important ecological role as primary excavators of nest and roost cavities. Many other wildlife species, including smaller woodpeckers, bluebirds, owls, and ducks, rely on these cavities for nesting and shelter.
Like most woodpecker species, pileated woodpeckers typically excavate their own nest and roost cavities in living or dead trees. However, there has been growing interest in providing artificial nest boxes for pileated woodpeckers, for several reasons:
- Suitable nest trees with large enough cavities are becoming more scarce in some areas due to forest fragmentation and loss of snags.
- Nest boxes may provide more reliable and productive nest sites than natural cavities.
- Boxes can be installed in strategic locations to attract birds for viewing and study.
- Installed nest boxes provide cavities immediately, compared to waiting for natural cavities to form in trees.
What do pileated woodpeckers look for in a nest site?
When choosing natural nest sites, pileated woodpeckers look for certain characteristics:
- Nest trees are usually large, mature trees at least 15 inches in diameter.
- They prefer trees with some heartwood decay, which makes excavation easier.
- The nest cavity is excavated on the underside of a limb, generally 20-60 feet above ground.
- The oval-shaped entrance hole is approximately 3 inches tall by 4 inches wide.
- The interior of the cavity is approximately a foot deep, and widens from the entrance.
These cavity requirements influence design recommendations for artificial nest boxes for pileated woodpeckers. The boxes should mimic natural cavities as closely as possible.
Nest box design for pileated woodpeckers
Experts offer the following guidelines for pileated woodpecker nest box design:
- Use untreated rough-cut lumber, at least 3/4 inch thick.
- Make drain holes in the box floor to allow rain to drain out.
- Line interior with wood shavings for nesting material.
- Install on large tree trunks, at least 15 feet above ground.
- Face the entrance away from prevailing winds and precipitation.
- Make the entrance hole an oval 3 x 4 inches.
- The interior floor space should be at least 6 x 6 inches.
- Depth from bottom to entrance hole should be 8-12 inches.
Larger nest boxes are generally recommended over smaller sizes. Some sources advise nest box volumes between 1.5 and 3 cubic feet. Attaching a Restrictor Plate around the entrance, to make it slightly smaller than the interior cavity, may help deter other species from entering.
Where to install nest boxes
Choosing proper placement for the nest box in the habitat is also important:
- Pick large trees, at least 15 inches diameter and 50 feet tall if possible.
- Dead trees with some heartwood decay are preferred.
- Select a spot at least 20 feet high, under a limb if possible.
- Face away from prevailing winds and precipitation.
- Clear vegetation and branches around the box.
- Install on the south or east side of trees for warmth.
- Keep visibility open for approach to the nest.
Putting up more than one nest box per territory increases the chances of use. Spacing multiple boxes at least 100 yards apart allows birds to choose the best cavity.
When to install the nest box
Pileated woodpeckers may roost in cavities year-round, but they only occupy nest cavities during the breeding season. The optimal time to install and check boxes is February through April. After excavating the nest, eggs are laid sometime in April or May.
It may take a pair of woodpeckers multiple seasons before accepting a nest box. Persistence is important, as boxes remain available for future years if not used initially. Check for signs of use or deterioration annually and replace old nesting material with fresh wood chips when needed.
What is the success rate of pileated woodpecker nest boxes?
Research on the effectiveness of artificial nest boxes specifically for pileated woodpeckers is fairly limited. However, some studies and monitoring results are available:
- One study of 117 nest boxes in Missouri had 14% occupancy over 7 years.
- Another study in Oregon found 30% occupancy over 5 years in 36 nest boxes.
- Average clutch size was 3-4 eggs in occupied boxes in these studies.
- Over 60% of occupied boxes successfully fledged young in the Missouri study.
- Pileated woodpeckers may roost in boxes more often than nest in them.
- Boxes may be more likely occupied in fragmented habitats with fewer natural cavities.
So while nest box occupancy rates appear lower than for smaller woodpecker species, they can provide valuable alternate nest sites for pileated woodpeckers where suitable natural cavities are limited. Installing boxes also contributes to conservation efforts for the species. With regular maintenance, boxes may attract breeding pairs or be used for roosting for many years.
Advantages and disadvantages of nest boxes
There are some notable potential advantages to using nest boxes for pileated woodpeckers:
- Provides cavity nesting opportunities in fragmented or cavity-deficient habitats.
- Cavities can be strategically located for easier observation and study.
- May increase nesting success compared to natural cavities.
- Immediately provides roosting and potential nest sites.
- Controls for cavity dimensions preferred by the species.
However, there are also some drawbacks or uncertainties to consider:
- Long-term persistence of nest box use is unknown.
- Difficult to predict which sites birds will use.
- May compete with natural cavities in healthy habitat.
- More research needed on nesting success in boxes.
- Requires annual maintenance and monitoring.
Other tips for attracting pileated woodpeckers
In addition to trying nest boxes, some other tips can help attract pileated woodpeckers to an area:
- Preserve standing dead trees and snags which provide natural nest sites.
- Allow dead limbs and tops on live trees for foraging.
- Retain trees with heartwood decay which aids excavation.
- Leave wooded corridors connecting fragmented habitats.
- Avoid pesticide use which reduces insect prey base.
- Leave logs and stumps on the ground for ant colonies.
- Use suet feeders with suet, fruit, or nuts to supplement diet.
Conclusion
Pileated woodpeckers play an important ecological role in forests, and providing artificial nest boxes can assist conservation efforts where suitable natural cavities are limited. While occupancy rates are lower than smaller woodpecker boxes, they may help attract breeding pairs and allow for easier observation. Nest boxes for pileated woodpeckers should follow design guidelines to mimic natural cavity characteristics. With annual maintenance and persistence, over the years, boxes may provide nesting or roosting sites for these unique, striking birds. Further research to track long-term occupancy and productivity of pileated woodpecker nest boxes will help advance understanding of their effectiveness as a conservation tool.