This is a Western Kingbird (Tyrannus verticalis) gathering nesting materials. Note the gray head and the yellowish underparts, these characters are easily seen and define this species. Additionally, the white stripe down the edge of the tail is also useful if it can be seen. Western Kingbirds belong to the Tyrant flycatcher family (Tyranidae). Beautiful little birds about the size of a Robin. This one was nesting in West Texas but I’ve seen them in Fort Worth, too.