Ladder-backed woodpeckers are small woodpeckers native to the southwestern United States and Mexico. They get their name from the ladder-like black and white pattern on their backs. Ladder-backed woodpeckers are somewhat uncommon across their range and have experienced population declines in recent decades. However, they remain fairly widespread and are not currently considered a threatened or endangered species. In this article, we’ll take a closer look at ladder-backed woodpecker populations, range, habitat needs, and conservation status to understand if these unique birds are truly rare.
Quick Facts on Ladder-Backed Woodpeckers
– Scientific Name: Picoides scalaris
– Average Length: 7 inches
– Wingspan: 13 inches
– Average Weight: 1.5 ounces
– Lifespan: Up to 12 years
– Diet: Insects, larvae, seeds, nuts
– Nesting: Tree cavities
– Range: Southwestern U.S., Mexico
– Conservation Status: Least Concern
Population and Declines
Ladder-backed woodpeckers have a large range across the arid regions of the southwestern United States and Mexico. Their breeding range extends from southern California, southern Nevada, southern Utah, Colorado, New Mexico, and western Texas down through Mexico to Oaxaca. Parts of their historic range have contracted, especially in California where they are now very limited in the southern coastal regions.
According to the North American Breeding Bird Survey, ladder-backed woodpeckers declined significantly between 1966 and 2015. Breeding populations in the U.S. diminished by an estimated 1.28% per year during this period, resulting in a cumulative decline of 53%. This indicates their populations have been cut in half over the last five decades.
However, Partners in Flight estimates the total adult ladder-backed woodpecker population in the U.S. and Mexico at around 3.5 million individuals. So while their numbers have dropped, they remain common within suitable habitat across the southwest. Their overall population size and wide distribution contribute to the ladder-backed woodpecker’s Least Concern conservation status.
Reasons for Declines
– Habitat loss
– Nest competition from European starlings
– Reduced insect prey availability
– Nest cavities usurped by other woodpecker species
Loss of native woodlands and changes in fire regimes have reduced optimal ladder-backed woodpecker breeding habitat across parts of their historic range. Ongoing urbanization in California has also diminished habitat availability and connectivity. Introduced European starlings often outcompete ladder-backed woodpeckers for nest cavities in some areas as well. Pesticide use lowering insect prey populations may also negatively impact these birds.
Range and Distribution
Ladder-backed woodpeckers inhabit arid pine-oak woodlands, mesquite scrublands, riparian corridors, and Sonoran desert scrub across their range. They are found up to 7,000 feet in elevation but are more common from 2,000 to 4,000 feet. Their range spans 24 degrees of latitude from the Transverse and Peninsular Ranges of southern California down to southern Mexico.
States and Regions
– California – Very limited along the Colorado River and in sparse oak woodlands of the Transverse and Peninsular Ranges
– Nevada – Widespread but localized throughout the southern half of the state
– Utah – Scattered populations frequent southwest canyons and scrublands
– Colorado – Occurs in the southwestern corner of the state
– New Mexico – Common resident of piñon-juniper forests statewide
– Texas – Found in western half of state in arid woodlands
– Mexico – Occurs down to Oaxaca; fairly common but declining in some areas
Within the U.S., ladder-backed woodpeckers are most abundant in the piñon-juniper forests and scrublands of New Mexico. They are also common locally in oak and mesquite habitats of central and western Texas.
Migration
Ladder-backed woodpeckers are non-migratory and reside year-round throughout their breeding range. They may make local movements and descend in elevation somewhat during the winter months but do not make substantial migratory journeys like many other North American woodpecker species. Their ability to excavate into agave stalks for food and nest in cavities allows ladder-backed woodpeckers to endure harsh conditions and inhabit the arid southwest residentially.
Habitat
Ladder-backed woodpeckers inhabit a variety of arid woodland and scrub habitats across their range. Their populations center around areas dominated by scrub oak, piñon pine, juniper, mesquite, cottonwood, and sycamore trees. Vegetation density and the presence of cacti and agave are also important habitat components.
Key Habitat Features
– Arid pine-oak and mesquite woodlands
– Riparian corridors along desert streams
– Piñon-juniper forests with a scrub oak understory
– Desert scrublands with agave and columnar cacti
– Sparse vegetation and open canopies
Ladder-backed woodpeckers favor open woodlands with ample sunny openings and low densities of small trees and shrubs. This allows them to forage on the ground for insects while also providing scattered trees for nesting. Their habitats often transition between desert scrub, grasslands, and open oak or piñon-juniper woodlands. The availability of agave and columnar cacti is also important, as they offer food sources and year-round moisture.
Territory Size
Ladder-backed woodpecker territories range from around 30 to 40 acres in size on average. Their home ranges can extend up to 100 acres or more in the most arid habitats. Both members of a mated pair share and defend the territory throughout the year against intrusions by other ladder-backed woodpeckers.
Elevation Range
From sea level along the Colorado River to around 7,000 feet in mountain canyons. Most abundant between 2,000 and 4,000 feet.
Identification
Ladder-backed woodpeckers are relatively easy to identify by their distinctive plumage. They display the following identification features:
– Small size – approximately 7 inches long
– Barred black and white ladder-like pattern on back
– Black and white banded underside
– White throat patch
– Black auricular patch behind eyes
– Black-spotted white outer tail feathers
– Dark bill
– White stripe down center of back on folded wings
– Males have red crown while females have black crown
The ladder-like markings on their backs give rise to their common name and make them unmistakable among North American woodpecker species. While superficially similar, they lack the high contrast coloration on the face and yellowish underparts of downy woodpeckers. Ladder-backed woodpeckers also have slower, deeper drumming than most other small woodpeckers. Their rattling call is distinctive.
Taxonomy
Ladder-backed woodpeckers belong to the following taxonomic classification:
Kingdom | Animalia |
Phylum | Chordata |
Class | Aves |
Order | Piciformes |
Family | Picidae (woodpeckers) |
Genus | Picoides |
Species | Picoides scalaris |
They are the only members of the Picoides genus found naturally in the southwestern U.S. Phylogenetic analysis shows ladder-backed woodpeckers are most closely related to downy woodpeckers and Nuttall’s woodpeckers.
Diet
The diet of ladder-backed woodpeckers consists mainly of insects and other arthropods. They also consume fruits, seeds, and sap from time to time.
Primary Foods
– Beetles
– Ants
– Caterpillars
– Grasshoppers
– Crickets
– Termites
Secondary Foods
– Berries
– Acorns
– Seeds
– Sap from agave and other succulents
Ladder-backed woodpeckers use their sharply pointed bills to dig into deadwood and tree bark crevices searching for beetle larvae, ants, and other insects. They also excavate into agave stalks and yucca cores for insects. These birds occasionally consume berries, seeds, and other plant foods as well. They are somewhat unusual among woodpeckers in regularly foraging on the ground for ants and other insects.
Nesting and Reproduction
The breeding season for ladder-backed woodpeckers runs from March through June across most of their range. They nest in tree cavities excavated by both sexes in dead or partially dead trees and branches.
Nest Sites
Favorite nest trees and cacti:
– Cottonwood
– Willow
– Mesquite
– Yucca
– Oak
– Agave
– Saguaro
Ladder-backed woodpeckers may nest solitarily or in loose colonies depending on habitat suitability. Cavities are excavated 10 to 60 feet above ground level on average. Entrance holes are extremely small, only 1 1/2 inches across.
Clutch Size
Average of 3-6 white eggs. Larger clutches correlated with ample food availability.
Incubation Period
About 12 days
Fledging Period
Young ladder-backed woodpeckers leave the nest at 26-31 days old.
Nesting Success
Fairly high. Estimated 60% of nests successfully fledge at least 1 young.
Weather, nest competition, and predation by snakes, rats, and screech owls reduce nest success. Parental care continues for several weeks after young fledge from the nest cavity. Ladder-backed woodpeckers typically raise one single brood per year.
Behavior and Adaptations
Ladder-backed woodpeckers exhibit several key behavioral adaptations for living in hot desert regions:
Cavity Roosting
Roosts inside tight tree cavities at night for insulation and shelter from elements. May cause a metabolic state of torpor on cold nights.
Delayed Breeding
Nest later in spring than other woodpecker species to match peak food availability.
Agave Feeding
Skillfully excavate into agave hearts for insects and moisture.
Soil Probing
Regularly forage on ground for ants and other arthropods. Strong toes adapted for scratching in loose soil.
Cactus Use
Glean insects from cacti and excavate nest cavities in saguaros and yuccas.
Ladder-backed woodpeckers also loosely maintain feeding territories throughout the year and exhibit longer-term pair bonding compared to many woodpecker species. Their agility and rapid, undulating flight allow them to forage actively in sparse desert trees and shrubs.
Vocalizations
Ladder-backed woodpeckers utilize vocalizations for communication between mates and defending territories. Their most common calls include:
Rattling Call
A fast rattling or choking sound often preceding drumming. Used to establish and defend nesting territories.
Whinny Call
A descending whinnying noise sounding like “keeah.” Serves as a location or contact call between mates and rivals.
Chirp
A short, sharp “pik” note. May signal alarm or excitement. Both sexes vocalize regularly.
The rattling territorial call of ladder-backed woodpeckers stands out for its distinctly mechanical and almost unbird-like quality. It lacks the boldness and carrying power of calls from larger woodpecker species. Vocalizations are often given in association with drumming on a resonant branch or tree trunk.
Drumming
Ladder-backed woodpeckers drum frequently from late winter through late spring to attract mates and defend nesting territories. Drumming consists of a slow series of 10 to 30 evenly spaced blows delivered at a rate of about 18 per second. The strokes are slower and deeper than downs woodpeckers and lack the ending roll typical of many other woodpecker drums.
Drumming Functions
– Establish and maintain territories
– Attract potential mates
– Communicate with partners
– Convey information on nest sites
Preferred Drumming Surfaces
– Dead branches or trunks
– Wooden utility poles
– Eaves or sides of wood-sided buildings
– Metal stovepipes or gutters
Males and females both drum, with males drumming more frequently early in the breeding season. Drumming often occurs near cavity nest sites. The acoustics of surrounding habitats influence drumming patterns and how far they carry.
Migration and Dispersal
Unlike most other North American woodpecker species, ladder-backed woodpeckers do not migrate and instead maintain year-round residency across their breeding range. There are no subspecies or geographic variations.
Some seasonal elevational movements may occur as birds disperse from breeding territories and withdraw from higher elevations in winter. But most individuals remain in the general vicinity of their nesting sites year-round.
Juveniles appear to disperse greater distances from natal sites than older birds. But even young ladder-backed woodpeckers only typically move a few miles between fledging and selecting their first breeding territory. Their sedentary nature and ability to tolerate hot, arid conditions allows populations to persist without migrating.
Conservation Status
The ladder-backed woodpecker is classified as a Species of Least Concern on the IUCN Red List due to its large range and global population size. Partners in Flight estimate there are approximately 3.5 million mature individuals. They are also listed as a bird of conservation concern by the U.S. Fish and Wildlife Service, primarily due to observed population declines.
Organization | Classification |
---|---|
IUCN Red List | Least Concern |
U.S. Fish and Wildlife Service | Bird of Conservation Concern |
Audubon | Not Currently Listed |
Habitat loss across parts of their U.S. and Mexican range poses the greatest long-term threat. Maintaining suitable breeding areas will be key to sustaining ladder-backed woodpecker populations into the future. While not rare overall, they merit ongoing monitoring and conservation focus in the arid southwest.
Fun Facts
Below are a few interesting facts about the unique ladder-backed woodpecker:
– Only woodpecker in North America to lack red on the head (females)
– One of few woodpecker species where both sexes regularly drum
– Known to follow army ants and ant swarms to feed on insects flushed from hiding
– Occasionally takes sap from hummingbird feeders
– Adds dried cactus spines to nest cavity entrance to deter predators
– Will readily nest in agave stalks and fence posts
– Used in Native American legends to teach lessons about work ethic and preparedness
Conclusion
In summary, ladder-backed woodpeckers have experienced significant population declines over the past half century leading to their designation as a bird of conservation concern. However, they remain fairly widely distributed across arid habitats of the southwestern U.S. and Mexico where they are locally common in some areas.
Current population estimates indicate there are at least several million ladder-backed woodpeckers across their global range. But habitat loss and nest competition continue to impact populations in parts of their range, especially California. Their relatively small size, lack of migratory habits, and ability to use marginal desert habitats likely contribute to the ladder-backed woodpecker’s resilience. While not currently rare or endangered, active management and protection of desert woodlands will be important for ensuring the future security of these uniquely adapted woodpeckers. They remain a key component of the avian communities of the arid southwest.