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Picoides scalarisladder-backed woodpecker

By Clyde Ashley

Geographic Range

From southwestern United States south to British Honduras (Lowther 2001).

Habitat

Wooded canyons, cottonwood groves, pine and pine oak woodlands, desert scrub, and desert grassland dominated by mesquite. Elevation range is from sea level to 2,600 meters. A xeric adapted woodpecker that is found in diverse habitat including mangrove swamps in Honduras (Short 1982, Lowther 2001).

  • Range elevation
    sea level to 2600 m
    to 8530.18 ft

Physical Description

Black with white barring on face, male has red crown patch, female lacks red crown patch, forehead black, and wings black with white spots, back is black with white bars. Similar in appearance to Nuttall’s woodpecker that has a cleaner white breast, and less spotting on flanks, and wider white bars on upper back. Length is 18.8 mm, weight 30.3g, and wing length (chord) 64mm. Zygodactylic feet and stiff tail feathers for climbing (Kaufman 2000, Lowther 2001).

  • Range mass
    21 to 48 g
    0.74 to 1.69 oz
  • Average mass
    30 g
    1.06 oz
  • Range length
    16 to 18 cm
    6.30 to 7.09 in
  • Range wingspan
    97.8 to 110 mm
    3.85 to 4.33 in
  • Average wingspan
    104 mm
    4.09 in

Development

Chicks are nearly naked and helpless (altricial) and confined to the nest (nidicolous). No information is available on fledging stage, however based on observations of the Nuttallii’s woodpecker (Picoides nuttallii) they leave the nest 15 to 16 days after hatching, and parental care continues for two weeks after leaving the nest (Lowther 2000, Lowther 2001).

Reproduction

Breeding pair formation starts in late January and continues through March. Incubation occurs from April through May. Clutch size varies from 4 to 6. Egg shape is oval or oval short. There is no information on nest selection and building, however nest are cavities in Joshua trees, Willow, Walnut, Cottonwood, Oak, Hackberry, Pine, and Mesquite. There is no information on parental care, fledging stage, immature stage, or the break up of mating pairs. Molt occurs after breeding from July to October. Hybridization occurs with Nuttall’s woodpecker where their ranges overlap (Short 1982, Lowther 2001).

  • Breeding season
    January through June
  • Range eggs per season
    4 to 6
  • Average eggs per season
    4
  • Average eggs per season
    4
    AnAge
  • Average time to hatching
    13 days
    AnAge
  • Range age at sexual or reproductive maturity (female)
    1 (low) years
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Range age at sexual or reproductive maturity (male)
    1 (low) years
  • Average age at sexual or reproductive maturity (male)
    1 years

Lifespan/Longevity

Longevity is 4.5 years based on banding. No data on adult survival rate. No known causes of mortality (Lowther 2001).

Behavior

Ladder-back woodpeckers have a swift and undulating flight. They also move by walking, hopping, and climbing. Males and females roost in separate cavities. This species does not migrate (Lowther 2001).

Communication and Perception

Food Habits

Main foods are insects and arthropods found by probe, pick or glean, bill flick, pry, and excavate. Foraging accomplished mainly on trunks and limbs of trees some reports of ground foraging (Lowther 2001).

Predation

No known predators for the species, but snakes routinely raid woodpecker nests, primarily the bull/gopher snakes. Cooper’s Hawks (Accipite cooperii), other accipiters, falcons and owls regularly predate on woodpeckers (Koenig et al. 1995).

Ecosystem Roles

By eating wood boring beetles and other insects, they help to control insect populations and their effect on trees (Short 1982).

Conservation Status

Contributors

Clyde Ashley (author), University of Arizona, Jorge Schondube (editor), University of Arizona.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

References

Bent, A. 1992. Life Histories of North American Woodpeckers. Bloomington, Indiana: Indiana University Press.

Kaufman, K. 2000. Birds of North America. New York: Houghton Mifflin Company.

Koenig, W., P. Stacey, M. Stanback, R. Mumme. 1995. Acorn woodpecker : Melanerpes formicivorus. Pp. 1 - 24 in A Poole, F Gill, eds. Birds of North America, No. 194. The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C..

Lowther, P. 2000. Nuttall's woodpecker : Picoides nuttallii. Pp. 1-12 in A Poole, F Gill, eds. Birds of North America, No. 555. The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union.

Lowther, P. 2001. Ladder-backed woodpecker : Picoides scalaris. Pp. 1-12 in A Poole, F Gill, eds. Birds of North America, No. 565. The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union.

Short, L. 1982. Woodpeckers of the World. Greenville, Delaware: Delaware Museum of Natural History , Foris Publications.

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