Picoides scalaris

This small, desert woodpecker is found across the southwestern United States’ Its range  extends from  southern California, southern Nevada, southwest  Utah,  southeast Colorado, western Oklahoma, and Texas south through Mexico to northern Central America to northeast Nicaragua (Howell and Webb 1995, Winkler et al.1995). This woodpecker tends to be more common in the northern half of its range.

Ladder-backed and Nuttall’s (P. nuttalli) woodpeckers form a superspecies. Although both species are present in California, their ranges are essentially allopatric (Am. Ornithol. Union 1998, Lowther 2001). In Texas the ranges of Ladder-backed and Downy (P. pubescens) woodpeckers are similarly divided by habitat preference.

This  species does not drum on wood (Winkler and Short 1978). The birds move rapidly and tend to cover fairly long distances between foraging sites. These woodpeckers also tend to turn and  twist, flutter and hop continually. During the mating period the birds show fluttering displays. Other displays include  crest raising, and tail or wing spreading. Males clearly dominate the  smaller females.  In addition to foraging and gleaning on trees for insects, they also take the fruit from several species of cacti.

DISTRIBUTION: The TBBA survey  showed the presence of  Ladder-backed Woodpecker predominantly west of a line approximating I-35 and the Balcones Escarpment from the Oklahoma border to New Braunfels, and south of a line from New Braunfels to Matagorda Bay. The greatest density of breeding records occurred south of the Nueces River.

Christmas Bird Count records and Breeding Bird Survey (BBS) data (Sauer et al. 2005) confirm the overall distribution of this resident species in the south and west of the state with high counts recorded at San Antonio and  Palmetto State Park near Gonzales. Lower numbers are regularly reported by Christmas Counts at Attwater Prairie Chicken National Wildlife Refuge (NWR), Victoria, and Aransas NWR.  The two highest BBS route totals for Ladder-backed Woodpecker were in  Kendall and Llano counties, both on the Edwards Plateau, with yearly averages of  11.7  and 7.8 woodpeckers, respectively (Price et al. 1995).

SEASONAL OCCURRENCE: Ladder- backed Woodpeckers are resident in Texas (Lockwood and Freeman 2004). The nesting season extends from April to early July (Oberholser 1974). TBBA atlasers found  nesting evidence from April  26 to a late date of June 22. These birds are usually seen as individuals or pairs, but may form small flocks after  the  breeding  season.

BREEDING  HABITAT: The Ladder- backed Woodpecker is found in very arid parts of the country, occupying in both the Sonoran and Chihuahuan deserts (Bent 1939, Lowther 2001).  It is found in  desert  scrub, riparian woodlands with deciduous trees such as cottonwoods and sycamores and in pine-oak woodlands.  It has few competitors in its desert habitats. In California,  the  Ladder-backed Woodpecker tends to be restricted to desert scrub (Short l97l), while the riparian woods are occupied by Nuttall’s Woodpecker.

The type of habitat preferred by this wood- pecker, desert scrub dominated by mesquite is not in short supply in Texas. It covers the entire western part of the state and undeveloped portions of the coastal plain. Current land management practices designed to eliminate mesquite and prickly pear cactus are expensive, laborious and  relatively ineffective. As a result; large tracts of land suitable for the Ladder- backed Woodpecker still exist in south and west Texas.

The nests are excavated in dead limbs, stumps, fence posts, yuccas, agaves and large cacti,   between 2 to 4.5 m (7-15 ft) off the ground. The male usually excavates the hole with some assistance from the female. The usual clutch is 3-5 (range 2-7) eggs (Oberholser 1974). Both sexes feed their young.

STATUS.  The  stability of Ladder-backed Woodpecker populations is readily seen when the map below is compared with  the distribution shown by Oberholser (1974). No significant differences appear in the distribution of breeding records through the western two-thirds of the state. The overall lack of sight records in the eastern part of  the state during the 1987-1992 TBBA period contrasts with the Christmas Bird Count records   and possibly suggests this species wanders widely in winter.

In the early 21^st century,  Ladder-backed Woodpecker is considered common to uncommon in the western two-thirds of Texas (Lockwood and Freeman 2004). Since 1966 the population of this species has changed by a statistically significant -1.6% per year. Since Texas supplies 129 of the 230 routes on which this species is recorded nationwide, it is not surprising that the national trend is similar (Sauer et al. 2005).

Literature cited.

American Ornithologists’ Union. 1998. Checklist of North American birds, 7^th ed. Am, Ornithol. Union, Washington, DC.

Bent,  A. C. 1939   Life histories of North American woodpeckers. U. S. Nat Mus Bull. 174.

Howell, S.N.G. and S. Webb. 1995 A guide to the birds of Mexico and northern Central America.
Oxford University Press, New York.

Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.

Lowther, P. E. 2001. Ladder-backed Woodpecker (Picoides scalaris). In The birds of North America, No. 565 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.

Price, J., S. Droege, and A. Price. 1995. The summer atlas of North American birds. Academic Press, New York.

Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, results and analysis 1966-2005. Version 6.2 2006. USGS Patuxent Wildlife Research Center, Laurel MD < http://www.mbr-pwrc.usgs.gov/bbs>

Short,  L. L.  1971  The systematics  and behavior of   some North American woodpeckers, genus Picoides (Ayes) Bull. Am. Mus. Nat. Hist., 145: 1-118.

Winkler,  H., D. A. Christie, and D. Nurney. 1995. Woodpeckers: an identification guide to the Woodpeckers of the world. Houghton Mifflin, Boston, MA.

Winkler,  H.  and L. L. Short,  1978  A  comparative analysis of acoustical signals in pied woodpeckers (Ayes Picoides). Bull . Am. Mus. Nat. Hist. 160: 1-109.