A twenty-foot-high wall seems of little significance to a bird like a Green Jay, which haunts wooded areas in the lowlands of Mexico, Belize, northern Guatemala and northwestern Honduras. Its range continues north up the Gulf Coast to the southern tip of Texas, but in recent years it has expanded northward as far as San Antonio. Meanwhile, the movements of regional rarities like Jaguars, ocelots, Jaguarundis and Sonoran pronghorn are restricted. The seasonal treks of important seed dispersers like Javelinas and coyotes are curbed, altering the distribution of the plants they carry, and by extension, the animals that depend on those plants. These effects add up and cascade in chaotic fashion and can ultimately impact the Green Jay in ways nobody can predict.