An effort to kill tamarisk, a salt-cedar shrub, has been stopped as it was found that the trees are used by an endangered bird, the southwestern willow flycatcher. The trees were planted by the millions in the 1930s as a way to fight soil erosion. It was later found that they have a tendency to overtake areas, replacing other plants, sucking up moisture, and increasing the frequency and intensity of fires. Several western and midwestern states had begun releasing many tamarisk leaf beetles, which eat the plants, in order to control the population. It came to the US Department of Agriculture's attention that the southwestern willow flycatcher uses the shrubs to nest in.
The southwestern willow flycatcher is an insectivorous bird, who also sprinkle their diets with fruit. They live and migrate throughout the southwestern US, Mexico, and northern South America. Because of the previously mentioned risk of fire to the tamarisk shrubs, fire is one of the main threats to the species, along with the recent killing off of the tamarisks.