like the nutria (Myocastor coypus) from South America, now common in the area. Feral pigs (Sus scrofa) "constitute one of the most serious conservation threats in Texas." They prey on natural populations of invertebrates, amphibians, reptiles, ground nesting birds, and rodents and are known to play a role in the transmission of disease including brucellosis, pseudorabies, and swine fever. Their forging habits involve rooting up and disturbing soils, reducing both the numbers of individual plants and animals and the number species in any given area. Birds: Three hundred species of migratory and nesting birds occur in the Big Thicket including the red-cockaded woodpecker, a state and federal endangered species. The extinct ivory-billed woodpecker once occurred in the Big Thicket. Reptiles: Sixty-one species of reptiles are known from the Big Thicket area including the alligator, 15 turtles, 12 lizards, and 33 snakes. Along with birds, reptiles are among the more commonly seen wildlife and they are an important part of the forest community or ecosystems. The American alligator (Alligator mississippiensis), although somewhat uncommon, occurs throughout the Big Thicket where sufficient water is found. However, alligators are abundant in the open marshland of Chambers and Jefferson counties to the south, where they bask in the sun unobstructed by forest trees. Turtle diversity in the American Gulf Coast states is among the highest in the world. The red-eared slider (Trachemys scripta) is the most common of the pond and river turtles, although river cooters (Pseudemys concinna), Mississippi map turtles (Graptemys pseudogeographica), Sabine map turtles (Graptemys sabinensis), and the rare chicken turtle (Deirochelys reticularia) all occur there. The worldwide distribution of the Sabine map turtle is limited to the Sabine and Neches rivers and adjacent drainages of southwest Louisiana. The once ubiquitous and abundant three-toed box turtle (Terrapene carolina) is still occasionally encountered in east Texas but its numbers plummeted in the late twentieth century, while the ornate box turtle (Terrapene ornata), at its eastern range limits, is known from a few county records in the area, as is the yellow mud turtle (Kinosternon flavescens). The Mississippi mud turtle (Kinosternon subrubrum), razorback musk turtle (Sternotherus carinatus), and common musk turtle (Sternotherus odoratus) spend much or their time foraging at the bottom of the murky waters but, occasionally can be seen basking or even on land moving between streams and ponds. Powerful swimmers, the largely aquatic spiny soft-shelled turtle (Apalone spinifera) is found throughout the