Live oak trees are a popular landscape tree because they are long lived and relatively care- free. But they are undergoing attacks all around south Texas from Datana caterpillars. Specifically Datana constricta.
http://www.bugguide.com shows that they are wreaking havoc as far north as Houston.
This tree had foliage this morning!
There are both chemical and organic treatments for caterpillars. Either way, you should be vigilant in checking your trees and other tasty green food plants. This family is going to put either insecticidal soap or a little dish soap in a hose end sprayer and wash the little buggers away! This treatment will need to be repeated.
If you want to read more about this caterpillar, Big Guide is a wonderful online resource.