Wrens

Some species of wrens in North America have suffered greatly from habitat losses associated with human activity. Other stressors have also been important, including the use of pesticides in agriculture, forestry, and in the shrubby parks and gardens in which some wrens breed.

The San Clemente Bewick's wren (Thryomanes bewickii leucophrys) was a resident breeder on San Clemente Island off southern California. This subspecies of the Bewick's wren became extinct through severe habitat damages that were caused by introduced populations of goats and sheep. These are generalized herbivores that essentially devoured the limited habitat of the San Clemente Bewick's wren, and that of other native local species of plants and animals.

Other populations of wrens have also declined in many places in North America. The leading causes of these changes are habitat losses associated with the conversion of natural ecosystems into land-uses associated with agriculture and housing, and to a lesser degree, with forestry. Pesticide use is also important in some cases.