Acorn Woodpecker, Melanerpes formicivorus
These spectacular woodpeckers, known for their clown faces and their raucous
"waka-waka!" calls, are conspicuous in oak woodlands throughout California.
Their range extends through the southwestern states and much of Mexico and
Central America, reaching its southernmost limit with a separate population in the
Colombian Andes. They store acorns in communal granaries, mostly trees both
live and dead, but also man-made wooden structures, stocking them in fall and
eating them when their other food sources (mostly flying insects) run short.
Above, a female, with the red crown patch surrounded by the black crown; males,
below, have a larger red patch extending to the white forecrown. The female
is taking an acorn from a granary tree in February, when the favored food items,
flying insects, are scarce. The male below is extending his long barb-tipped tongue,
characteristic of woodpeckers, adapted for exploration of crevices and holes in trees.
In some woodpecker species the tongue is so long that at rest it loops around the back
of the bird's skull.
Photos of Acorn Woodpeckers in flight--the one above a male carrying an acorn away from a granary tree; below, two males harassing a pair of crows that have intruded into the territory of their woodpecker family group.
Male on granary tree, showing mostly white underwing and underparts.
The image above and the two below, taken in October, show Acorn Woodpeckers engaging in out-of-breeding-season sexual behavior
that, as Birds of North America Online describes it, "mimics normal copulatory behavior in many respects but serves a more social function because sperm is not transferred between individuals." Birds "mount each other" in "both heterosexual and homosexual combinations." The two birds pictured here have black surrounding the red on the crown and so appear to be females, but the forward bird has two separate red patches, an unusual configuration that led one experienced observer to speculate that it might be an immature male still growing in its larger adult red patch. If that were the case, the female would be mounting the male, the reverse of the case for reproductive copulation.
A female Acorn Woodpecker apparently storing a piece of meat for future
consumption. This species is not considered carnivorous, and I have not come
across any other photographs showing an Acorn Woodpecker eating or preparing
to eat meat. These birds' favorite food is insects, mainly captured in flight;
next come tree sap and acorns -- the latter being mostly a reserve food for winter,
when flying insects are scarce. But experts have told me that Melanerpes
woodpeckers tend to be opportunistic foragers, and other species in the genus
have been reported occasionally eating raw flesh. The item, shown here in close-up,
could be part of a reptile or a bird, even possibly part of a nestling Acorn Woodpecker.
The young of this species have high mortality rates, especially from starvation,
because the supply of the backup food source, acorns, can fluctuate drastically.
A fledgling that starved to death could be harvested as food, keeping other nestlings
alive in years of scarcity.
A male storing an acorn in the bottom of the branch of a snag used by a communal Acorn Woodpecker group as a granary. This branch looks close to collapse from the number of holes that have been drilled in it over the years. These birds often prefer storage holes on the underside of branches, where they are less likely to be discovered. The feet and tail feather of woodpeckers are suited to upside-down perching like this.
A nest in the process of excavation, with a female present. Acorn Woodpeckers are,
in company with one other woodpecker species, the Red-cockaded Woodpecker,
communal nesters, with an average of five and up to fifteen birds occupying a single
nest, sometimes including more than one egg-laying female and several year-old
birds acting as helpers.
A male Acorn Woodpecker on one of the eaves decorating Kubo Bed and Breakfast in the bird mecca of Madera Canyon, Arizona. The brown and dull black on the upperside of the flight feathers contrast with the glossy black of the back and head. This image and the one just above also show the exceptionally sturdy tail feathers, characteristic of woodpeckers, which act as braces helping them to perch comfortably on vertical surfaces, or perch upside-down as shown further up the page.