monogamous when it comes to breeding, but go solitary throughout the winter. Status and conservation In 2016, the Bewick's wren was listed as least concern on the IUCN Red List of threatened species due to the size of its range and estimates of its population size. However, ornithologists have noted a severe decline in its eastern range and parts of its western range. In particular, it has virtually disappeared from east of the Mississippi. In 1984, the state of Maryland classified the Bewick's wren as endangered under its Maryland Endangered Species Act of 1971. Despite this classification, no breeding pairs of Bewick's wrens are known to remain in Maryland. In 2014, the North American Bird Conservation Initiative placed the eastern Bewick's wren on its watch list. Several theories have been proposed to explain its decline in its eastern range, including pesticide use and competition from other bird species. The most likely reason seems to be competition from house wrens. House wrens compete with Bewick's wrens for similar nesting sites. House wrens will destroy both the nests and eggs of Bewick's wrens. The reforestation of once open land has also negatively impacted the eastern Bewick's wrens. In California, habitat loss due to development has impacted the Bewick's wren. In San Diego, the development of canyons has led to the gradual decline of native bird species, including the Bewick's wren. In Washington, development has actually benefited the Bewick's wren, leading to an increase in its population. However, this has coincided with the decline of the Pacific wren thanks to increased competition between the two species. References External links Bewick's wren - Thryomanes bewickii - USGS Patuxent Bird Identification InfoCenter Bewick's wren Species Account – Cornell Lab of Ornithology Bewick's wren Birds of Mexico Birds of the United States Native birds of the Western United States Fauna of the California chaparral and woodlands Fauna of the Channel Islands of California Bewick's wren Bewick's wren