Why is it Vulnerable and Why is it Endangered?
In simplistic terms, timber harvesting of the southern pine forests has resulted in a loss of mature pine forest habitat, habitat that the RCW needs for food and shelter. Currently, much of the forests in East Texas are managed for fiber production which usually means a short rotation age.
Basically, the trees are too young and too small for RCWs to excavate cavities for roosting and nesting, and the stands are usually too dense for RCWs to search for insects on which to feed. In many pine forests where sawtimber-sized trees are available for the RCWs to excavate cavities, the hardwood midstory is typically so dense that the RCW avoids these areas.
Scientists believe that RCWs adapted to excavating cavities in live pine trees to take advantage of the sappy resin which flows from wounds in the tree (see photo on page 1).
The RCW pecks resin wells on the trees in which they have excavated cavities. The resulting resin “barrier” effectively prevents predators such as rat snakes, which do climb pine trees as they search for food, from climbing the trees. However, an abundance of midstory hardwoods can allow predators to reach an RCW cavity tree via hardwood limbs. The rat snake, for example, can climb the hardwood to reach the cavity and eat RCW eggs or young. This is one of the reasons why it is believed that hardwood encroachment in a pine stand causes the RCW to abandon their cavity trees. If they don’t abandon these densely stocked sites, they might end up in the stomach of a rat snake!
Historical accounts of the pine forests in East Texas depict large old trees, many RCWs and an open, grassy understory among a sparse pine overstory (canopy). It has been said: “Once upon a time, you could ride a horse at full gallop through the pine forests of East Texas.” In modern times, that would be virtually impossible due to the thick brush. It is believed that natural, frequent fires burned the forests of East Texas.These fires promoted the open, grassy character of the forest, while reducing most species of hardwoods in the uplands where the RCW lived. The harvesting of these forests and the lack of frequent fires have essentially changed the character of the forests, causing many species dependent on this fire-maintained ecosystem to decline. Among the declining species are: RCW, Bachman’s sparrow, Eastern wild turkey, American kestrel, northern bobwhite (quail), Texas trailing phlox and Louisiana pine snake. (See Partners in Flight for more information.)
Wildlife Diversity Program
Texas Parks and Wildlife Department
4200 Smith School Road
Austin, TX 78744
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