The Acorn Woodpecker: Master of Granaries and Drummers of the Forest

Welcome to our blog post dedicated to the fascinating Acorn Woodpecker (Melanerpes formicivorus). Join us as we delve into the world of this remarkable bird species, known for its unique behaviors, striking appearance, and vital role in forest ecosystems.

Field Identification

Acorn Woodpecker

The Acorn Woodpecker, scientifically known as Melanerpes formicivorus, is a medium-sized woodpecker species with a distinct appearance. It has a black back and head, a white forehead, and a vibrant red crown. Its wings display a combination of black and white patterns, and both males and females share similar plumage.

Systematics History

The Acorn Woodpecker belongs to the Picidae family, which includes various woodpecker species. It falls under the genus Melanerpes, which comprises woodpeckers known for their colorful plumage and unique foraging techniques.


Several subspecies of the Acorn Woodpecker have been identified, with variations in plumage and distribution. These subspecies include the California Acorn Woodpecker (Melanerpes formicivorus bairdi) and the San Pedro Martir Acorn Woodpecker (Melanerpes formicivorus angustifrons).


The Acorn Woodpecker is native to parts of North America, primarily found along the western coastal regions. Its range extends from southern Oregon and California down to the mountains of Central America.


This woodpecker species thrives in diverse habitats, including oak woodlands, pine-oak forests, and mixed coniferous forests. It has a preference for areas with mature trees, as they provide suitable nesting cavities and an abundant supply of acorns.


While Acorn Woodpeckers are not known for long-distance migrations, they may exhibit seasonal movements within their range in response to food availability and nesting requirements.

Diet and Foraging

As their name suggests, Acorn Woodpeckers have a specialized diet focused on acorns. They are known for their unique storage behavior, where they create “granaries” by drilling holes in trees and filling them with acorns. These granaries serve as a crucial food source during lean periods. In addition to acorns, they also consume insects, fruits, berries, and tree sap.

Sounds and Vocal Behavior

The Acorn Woodpecker has a distinctive vocal repertoire. Their calls include a variety of rattling and chattering sounds, often heard during territorial disputes and group interactions. They also engage in “drumming” behavior, using rapid and repetitive drumming sounds on resonant surfaces to communicate with other woodpeckers and establish territory boundaries.

Breeding Habits

Acorn Woodpeckers are cooperative breeders, with small groups of individuals contributing to nest construction and rearing of young. Multiple males and females may share a nesting cavity, and group members participate in incubation, feeding, and protecting the offspring. Breeding typically occurs between April and July.

Conservation Status

The Acorn Woodpecker is currently listed as a species of Least Concern on the IUCN Red List. While some localized populations may face threats from habitat loss and fragmentation, the species as a whole maintains stable populations across its range.

Frequently Asked Questions (FAQ)

Q1: What is the purpose of the Acorn Woodpecker’s granaries?

A1: The granaries created by Acorn Woodpeckers serve as a storage system for acorns, ensuring a steady food supply during winter or when acorn availability is low.

Q2: How do Acorn Woodpeckers protect their acorn stash from other animals?

A2: Acorn Woodpeckers defend their granaries vigorously by engaging in group defense behavior, chasing away potential intruders and vocalizing to alert group members.

Q3: What is the significance of the Acorn Woodpecker’s drumming behavior?

A3: Drumming is a form of communication for Acorn Woodpeckers, used to establish territory boundaries, attract mates, and communicate with other woodpeckers.

Q4: How do Acorn Woodpeckers contribute to forest ecosystems?

A4: Acorn Woodpeckers play a vital role in seed dispersal, particularly for oak trees, by caching and forgetting acorns, which can lead to the establishment of new oak trees in different locations.

Q5: How can I attract Acorn Woodpeckers to my backyard?

A5: Providing suitable nesting sites, such as dead trees or nest boxes, along with a consistent supply of acorns and insect-rich trees, can attract Acorn Woodpeckers to your backyard.

The Acorn Woodpecker is a remarkable species with its striking appearance, unique foraging behaviors, and important ecological role. By understanding and appreciating these woodpeckers, we can work towards their conservation and the preservation of the diverse ecosystems they inhabit.

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