Migration Info During winter, the Wood Thrush is most common in primary forests along both coasts of Central America. Unfortunately, coastal primary forests are disappearing at an alarming rate. In United States, forest fragmentation has greatly reduced the amount of breeding habitat and made this species more vulnerable to cowbird parasitism. Wood Thrushes are primarily trans-Gulf migrants, spending considerable time fattening up on fruits before attempting to cross the Gulf. Upon arrival along the U.S. Gulf coast, they usually stop for two or three days to feed before continuing northward. One population moves quickly along the east coast, while another pulse of birds pushes northward through the Mississippi River valley.