Woodpeckers belong to a large and varied family of birds known as Picidae. The family is divided into subfamilies and those subfamilies are divided into tribes. The Melanerpini tribe is a group native to the Mogollon Highlands and includes Acorn Woodpecker (Melanerpes formicivorus), the Gila Woodpecker (Melanerpes pygialis), among others.
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Different species of woodpeckers share some common characteristics. All woodpeckers have exceptionally strong tails to aid in climbing and perching on tree trunks. Most are territorial and generally monogamous, having one mate at a time. Their nests are excavated in dead or living tree trunks and both parents work on nest building as well as incubating the eggs. The female woodpecker lays from three to twelve white elliptical eggs in April. They hatch in June after an incubation period of 9-19 days. Most woodpecker species have only one brood each year but the Gila Woodpecker is an exception, hatching as many as three broods in a good year. Baby woodpeckers are blind and featherless upon hatching. Both parents care for the young birds until they fledge at 18-30 days of age but the young may remain with their parents until fall. Across species, the woodpecker diet consists mainly of insects in summer, seeds in winter, and occasionally fruit.
An iconic woodpecker of the Central Arizona Highlands is the Acorn Woodpecker. Acorn woodpeckers live in groups called colonies and practice cooperative breeding. Each colony consists of up to five males, two females and several juveniles from previous years. All the adults take part in nesting and feeding tasks. The acorn woodpecker is a very distinctive-looking bird—about nine inches long with shiny black feathers on the back, white breast & throat, bright red head markings and white eyes. Males and females are similar in appearance, except that the female’s red cap and her beak are slightly smaller.
There are two trees upon which the Acorn Woodpecker is highly dependent: the oak tree (for acorns which are their primary winter food source) and the ponderosa pine. In addition to making nesting cavities in the Ponderosa Pine trunks, the Acorn Woodpecker also pecks out numerous small holes, filling each one with a single acorn. These trees are called “granaries” and are fiercely defended by the birds which claim them. They will also claim and defend “their” oak tree, scolding with their raucous voice and chasing away other birds and squirrels which would like to share the tree’s bounty.
Ponderosas provide homes for many kinds insects as well, from small beetles and carpenter ants, to large cicadas. The female cicada lays her eggs beneath the bark of trees, including ponderosas, where they remain until hatching to burrow under the ground as larvae. Several species of bark beetles live in the pines. Some can be beneficial to the tree, seeking out and eating other beetles that may be actively damaging to the tree. Unless the tree has been stressed by drought, fire or climate change, tree and beetles live together, but if the tree has been too stressed, the scales tip in favor of the beetles. Whole forests have been decimated in this way.
Acorn woodpeckers adapt well to urban life. They will substitute a utility pole for a granary tree and home. They readily visit suet and seed feeders, frequently chasing away smaller birds, and have even been observed visiting hummingbird feeders! One might wonder how it is possible for them to feed at a hummer feeder. Their tongues are long, just like a hummingbird tongue, that can be used to pry bugs from under tree bark, but in this case can also be used to obtain a sweet treat!
Contributed by HCNH Naturalist Sandy Stoecker
