Acorn Woodpecker
Encyclopedia
The Acorn woodpecker is a medium-sized woodpecker
, 21 cm long with an average weight of 85 g.
s in the hills of coastal areas and foothills of California and the southwestern
United States
south to Colombia
. This species may occur at low elevations in the north of its range, but rarely below 1000m in Central America
, and it breeds up to the timberline. The breeding pair excavate a nest in a large cavity in a dead tree or a dead part of a tree. A group of adults may participate in nesting activities: Field studies have shown that breeding groups range from monogamous pairs to breeding collectives of seven males and three females, plus up to 10 nonbreeding helpers
. Young have been found with multiple paternity.
they are green and have a pink toungh.
s for food. In some parts of their range (e.g., California), the woodpeckers create granaries
or "acorn trees" by drilling holes in dead trees, dead branches, telephone poles and wooden buildings. The woodpeckers then collect acorns and find a hole that is just the right size for the acorn. As acorns dry out, they are moved to smaller holes and granary maintenance requires a significant amount of the bird's time. They also feed on insects, sap
, and fruit.
s. Acorns are such an important resource to the California populations that Acorn Woodpeckers may nest in the fall to take advantage of the fall acorn crop, a rare behavior in birds. Acorn Woodpeckers can also be seen sallying
from tree limbs to catch insects, eating fruit and seeds, and drilling holes to drink sap. The Acorn Woodpecker will use any human-made structures to store acorns, drilling holes into fence posts, utility poles, buildings, and even automobile radiators. Occasionally the woodpecker will put acorns into places where it cannot get them out. Woodpeckers put 220 kg (485 lb) of acorns into a wooden water tank in Arizona. In parts of its range the Acorn Woodpecker does not construct a granary tree, but instead stores acorns in natural holes and cracks in bark
. If the stores are eaten, the woodpecker will move to another area, even going from Arizona
to Mexico
to spend the winter.
This bird is a permanent resident throughout its range. They may relocate to another area if acorns are not readily available. It is sedentary and very sociable.
ing, roosting and granary sites to help preserve the Acorn Woodpeckers population.
is believed to have patterned the call of his cartoon character Woody Woodpecker
on that of the acorn woodpecker, while patterning his appearance on that of the Pileated Woodpecker
which has a prominent crest.
Woodpecker
Woodpeckers are near passerine birds of the order Piciformes. They are one subfamily in the family Picidae, which also includes the piculets and wrynecks. They are found worldwide and include about 180 species....
, 21 cm long with an average weight of 85 g.
Description
The adult Acorn Woodpecker has a brownish-black head, back, wings and tail, white forehead, throat, belly and rump. The eyes are white.There is a small part on the small of their backs were there are some green feathers. The adult male has a red cap starting at the forehead, whereas females have a black area between the forehead and the cap. The white neck, throat and forehead patches are distinctive identifiers.When flying,they take a few flaps of their wings and drop a foot or so.You can see white circles on the wings while flying. Acorn woodpeckers have a call that is almost like they are laughing.Breeding communities
The breeding habitat is forested areas with oakOak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
s in the hills of coastal areas and foothills of California and the southwestern
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...
United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
south to Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. This species may occur at low elevations in the north of its range, but rarely below 1000m in Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, and it breeds up to the timberline. The breeding pair excavate a nest in a large cavity in a dead tree or a dead part of a tree. A group of adults may participate in nesting activities: Field studies have shown that breeding groups range from monogamous pairs to breeding collectives of seven males and three females, plus up to 10 nonbreeding helpers
Helpers at the nest
Helpers at the nest is a term used in behavioural ecology and evolutionary biology to describe a social structure in which juveniles and sexually mature adolescents of either one or both sexes, remain in association with their parents and help them raise subsequent broods or litters, instead of...
. Young have been found with multiple paternity.
Food and homes
Acorn woodpeckers, as their name implies, depend heavily on acornAcorn
The acorn, or oak nut, is the nut of the oaks and their close relatives . It usually contains a single seed , enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1–6 cm long and 0.8–4 cm broad...
s for food. In some parts of their range (e.g., California), the woodpeckers create granaries
Granary
A granary is a storehouse for threshed grain or animal feed. In ancient or primitive granaries, pottery is the most common use of storage in these buildings. Granaries are often built above the ground to keep the stored food away from mice and other animals.-Early origins:From ancient times grain...
or "acorn trees" by drilling holes in dead trees, dead branches, telephone poles and wooden buildings. The woodpeckers then collect acorns and find a hole that is just the right size for the acorn. As acorns dry out, they are moved to smaller holes and granary maintenance requires a significant amount of the bird's time. They also feed on insects, sap
Sap
Sap may refer to:* Plant sap, the fluid transported in xylem cells or phloem sieve tube elements of a plant* Sap , a village in the Dunajská Streda District of Slovakia...
, and fruit.
Defense and storing
The acorns are visible, and the group defends the tree against potential cache robbers like Steller's Jays and Western Scrub JayWestern Scrub Jay
The Western Scrub-Jay , is a species of scrub-jay native to western North America. It ranges from southern Washington to central Texas and central Mexico. It comprises three distinct subspecies groups, all of which may be separate species...
s. Acorns are such an important resource to the California populations that Acorn Woodpeckers may nest in the fall to take advantage of the fall acorn crop, a rare behavior in birds. Acorn Woodpeckers can also be seen sallying
Hawking (birds)
Hawking is a feeding strategy in birds involving catching flying insects in the air. The term usually refers to a technique of sallying out from a perch to snatch an insect and then returning to the same or a different perch...
from tree limbs to catch insects, eating fruit and seeds, and drilling holes to drink sap. The Acorn Woodpecker will use any human-made structures to store acorns, drilling holes into fence posts, utility poles, buildings, and even automobile radiators. Occasionally the woodpecker will put acorns into places where it cannot get them out. Woodpeckers put 220 kg (485 lb) of acorns into a wooden water tank in Arizona. In parts of its range the Acorn Woodpecker does not construct a granary tree, but instead stores acorns in natural holes and cracks in bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
. If the stores are eaten, the woodpecker will move to another area, even going from Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to spend the winter.
Breeding behavior
In California, Acorn Woodpeckers breed from May – July. An Acorn Woodpecker group may consist of 1-7 male breeders that compete to mate with 1-3 females. The nest is excavated in a large tree, which may also be a granary tree. Tree cavities are created in both dead and living trees and snags and nest holes are reused for many years. Females typically lay 5 eggs that are incubated for 11–14 days. Male and females incubate and tend to their young. Non-breeding helpers (young from previous years) often help with incubation and other parental duties. The young leave the nest and take their first flight at approximately 30–32 days after hatching and return to the nest to be fed for several weeks.Breeding female
In groups with more than one breeding female, the females put their eggs into a single nest cavity. A female usually destroys any eggs in the nest before she starts to lay, and more than one third of all eggs laid in joint nests are destroyed. Once all the females start to lay, they stop removing eggs.This bird is a permanent resident throughout its range. They may relocate to another area if acorns are not readily available. It is sedentary and very sociable.
Threats and degradation
Acorn Woodpeckers like many other species are threatened by habitat loss and degradation. Competition for nest cavities by non-native species is an ongoing threat in urbanized areas. Conservation of this species is dependent on the maintenance of functional ecosystems that provide the full range of resources upon which the species depends. These include mature forests with oaks capable of producing large mast crops and places for the woodpeckers to nest, roost, and store mast. Residents are encouraged to preserve mature oak and pine-oak stands of trees and to provide dead limbs and snags for nestNest
A nest is a place of refuge to hold an animal's eggs or provide a place to live or raise offspring. They are usually made of some organic material such as twigs, grass, and leaves; or may simply be a depression in the ground, or a hole in a tree, rock or building...
ing, roosting and granary sites to help preserve the Acorn Woodpeckers population.
Popular culture
Walter LantzWalter Lantz
Walter Benjamin Lantz was an American cartoonist, animator, film producer, and director, best known for founding Walter Lantz Productions and creating Woody Woodpecker.-Early years and start in animation:...
is believed to have patterned the call of his cartoon character Woody Woodpecker
Woody Woodpecker
Woody Woodpecker is an animated cartoon character, an anthropomorphic acorn woodpecker who appeared in theatrical short films produced by the Walter Lantz animation studio and distributed by Universal Pictures...
on that of the acorn woodpecker, while patterning his appearance on that of the Pileated Woodpecker
Pileated Woodpecker
The Pileated Woodpecker is a very large North American woodpecker, almost crow-sized, inhabiting deciduous forests in eastern North America, the Great Lakes, the boreal forests of Canada, and parts of the Pacific coast. It is also the largest woodpecker in America.Adults are long, and weigh...
which has a prominent crest.
External links
- Cornell Lab of Ornithology species account
- Acorn Woodpecker (Archived 2009-10-24), a bibliographic resource
- USGS
- Acorn Woodpecker videos, photos & sounds on the Internet Bird Collection
- Stamps (for El SalvadorEl SalvadorEl Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
, MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
) with RangeMap - Acorn Woodpecker photo gallery VIREO-(distinctive white face-throat patches)
- Photo-High Res FWS-Fish & Wildlife Service: Digital Repository