Sapsuckers are Keystone Species
by Ro Wauer
Sapsuckers, with a name that sounds like it was invented by cartoonists, are one of our most interesting wintertime residents. They are referred to as "keystone species" because of their importance in the wildlife community. Wherever they occur, other birds take advantage of the sapsucker's habit of maintaining sap wells. These are tiny holes drilled in various trees and large shrubs from which the sapsucker obtains much of its nutrients. The flowing sap is licked up by sapsuckers, and numerous other birds, mammals, lizards, and insects also feed on the sap or prey on the various creatures that are attracted to the site. Sapsuckers, therefore, often are the center of an active community.
The widespread sapsucker that occurs in South Texas during the winter months is the yellow-bellied sapsucker; Williamson’s, red-naped and red-breasted sapsuckers are rare or uncommon species found only in the Trans-Pecos mountains. Although a member of the woodpecker family, sapsuckers differ from typical woodpeckers in several ways. Most importantly, their diet consists primarily of sap, although insects, fruit and berries are also part of their diet. Insects are vitally important when feeding young. Sapsucker tongues have evolved with featherlike projections, enhancing their ability to lap the gooey sap. Woodpecker tongues possess barb-like projections that allow them to probe into holes drilled into trees and shrubs and retrieve insects.
Our wintering yellow-bellied sapsucker can readily be distinguished from other woodpeckers by their medium size, red forehead and throat, black-and-white face, black chest, and yellow belly. The slightly smaller ladder-backed woodpecker, a year-round resident, lacks the red throat and black chest, although males possess a red cap; they possess a black-and-white barred back, ladder like markings. The larger red-bellied woodpecker is fairly common in the northern half of the South Texas region, while the similar golden-fronted woodpecker occurs only in the southern portion of our region. Their ranges overlap in Victoria County. Both of these larger woodpeckers have a barred back and grayish underparts. In addition, the northern flicker is also fairly common in winter; it is easily identified by its yellow flight feathers and spotted breast. The much larger pileated woodpecker, the woody-woodpecker look-alike, is usually limited to riparian areas. And the red-headed woodpecker of the eastern forests is only rarely found in South Texas.
Yellow-bellied sapsuckers only winter in South Texas, usually arriving in mid-October and departing in April. Evidence of their activities is easily found by the lines of small test holes on the trunks of various trees and shrubs; cedar elm, sugarberry and live oak seem to be preferred. They maintain only the most productive holes. Their nesting grounds lie far to the north of Texas, across the northern tier of states and northward into Alaska and east to Newfoundland. They overwinter throughout the southeastern states and most of Texas eastward to the southern Atlantic states, and a few occasionally reach the Caribbean Islands.
Their presence in our neighbor is worth noting. It is a fascinating species and truly an important member of the wildlife community.