Woodpeckers are unique birds known for their distinctive pecking behavior. This action is not random; it serves various biological purposes essential for their survival and reproduction. The specialized anatomy of a woodpecker, including its bill and skull, allows it to perform these repetitive high-impact actions without incurring injury.
Hunting for Meals
Woodpeckers primarily peck to locate and access food sources within trees. Their diet consists of insects, particularly wood-boring invertebrates like beetle larvae and ants. They listen for insects moving beneath the bark or within the wood, then use their strong bills to excavate holes. Foraging holes are often irregular in shape, reflecting their exploratory search. Once a cavity is created, their long, barbed, sticky tongues extract prey from deep within crevices and tunnels.
Sapsuckers, a type of woodpecker, peck to consume tree sap. They create small, neat rows of holes, often horizontal or vertical, to access sap. These “sap wells” allow them to lap up the sugary fluid with brush-tipped tongues. The sap also attracts insects, which sapsuckers consume, supplementing their diet.
Building Homes
Woodpeckers excavate tree cavities for nesting and roosting. These cavities provide a secure place to raise young, protecting eggs and chicks from predators and environmental elements. They also offer a safe haven for individual birds to sleep, especially in colder periods, as the insulated space is warmer than outside air.
Woodpeckers prefer dead or decaying trees, or those with softened heartwood from fungal infections, as the wood is easier to excavate. While they may create exploratory holes, they often focus on one deep cavity for nesting, which can take weeks to complete. These excavated cavities are important for woodpeckers and become available to a variety of other cavity-nesting birds and animals that cannot create their own holes, making woodpeckers “ecosystem engineers.”
Sounding the Alarm
Beyond foraging and excavation, woodpeckers peck rapidly on resonant surfaces for communication, a behavior known as drumming. Drumming differs from foraging pecks, which are slower and quieter. Drumming produces loud, rhythmic sounds for various communicative purposes within their species.
Drumming declares territory, warning other woodpeckers to stay away. It also attracts mates, announcing presence and readiness to breed, similar to how songbirds use vocalizations. Both male and female woodpeckers drum, especially during the breeding season in late winter and early spring. Woodpeckers select surfaces that amplify sound, such as hollow trees, utility poles, or metal flashing, to ensure their message travels far.
Why Some Structures are Targeted
Woodpeckers sometimes peck on human-made structures like houses, fences, or utility poles, which can perplex property owners. They are not intentionally causing damage; rather, their behavior results from mistaking these structures for suitable natural habitats or finding them appealing for other biological reasons. For instance, wooden siding or eaves might resonate like a dead tree, leading a woodpecker to believe it is an appropriate site for drumming or foraging.
Structures may also attract woodpeckers if they harbor insects, providing an unintended food source. Birds might detect insect activity within the wood and begin pecking to access them. Materials like metal flashing, gutters, or hollow siding can offer excellent resonant qualities, making them attractive surfaces for drumming to communicate territorial claims or attract mates. Protected corners or softer materials on buildings might appear to offer potential for roosting or nesting, prompting excavation attempts.